Updated CDC Zika Laboratory Testing Guidance

Moderator: William Koehne

Presenters: Christy Ottendorfer, Ph.D.; Matthew J. Binnicker, Ph.D., D(ABMM); Grace Kubin, Ph.D.

Date/Time: December 1, 2016, 2:00 - 3:00 pm ET

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Coordinator: Welcome and thank you for standing by. At this time all participants are in a listen-only mode until the question and answer session of today’s conference. At that time you may press Star then the Number 1 on your phone to ask a question. I would like to inform all parties the today’s conference is being recorded. If you have any objections you may disconnect at this time. I would now like to turn the conference over to William Koehne. Thank you, you may begin.

William Koehne: Thank you (Jennifer). Good afternoon. I’m William Koehne and I’m representing the Clinician Outreach and Communication Activity, COCA with the Emergency Risk Communications Branch at the Centers for Disease Control and Prevention. I’m delighted to welcome you to today’s COCA call Updated CDC Laboratory Testing Guidance. You may participate in today’s presentation by audio only via webinar or you may download the slides if you are unable to access the webinar. The PowerPoint slide set and the webinar link can be found on our COCA Web page at emergency.cdc.gov/coca.

Free continuing education is offered for this COCA call. Instructions on how to earn continuing education will be provided at the end of the call. CDC, our planners, presenters and their spouses/partners wish to disclose that they have no financial interest or other relationships with the manufacturers of commercial products, suppliers of commercial services or commercial supporters. Planners have reviewed the content to ensure there is no bias. This presentation will not include any discussion of unlabeled use of products or products under investigational use.

At the end of the presentation you’ll have the opportunity to ask the presenters. On the phone dialing Star 1 will put you in the queue for questions and you may submit questions through the Webinar system at any time during the presentation by selecting the Q&A tab at the top of the webinar screen and typing in your question. Questions are limited to clinicians who would like information about Zika and laboratory testing. For those with media questions please contact CDC media relations at 404-639-3286 or send an email to media@cdc.gov. If you are a patient please refer your questions to your healthcare provider.

At the conclusion of today’s session the participants will be able to: describe all available food and drug administrative - administration emergency use authorizations for Zika virus assays; discuss Zika virus testing methods including molecular and antibody detection; explain the role of public health laboratories, clinicians, and health departments and Zika virus testing; and identify Zika virus laboratory testing algorithms and resources.

Today’s first presenter is Dr. Christy Ottendorfer. Dr. Ottendorfer is currently serving as a team lead of the Zika Lab Team Task Force at CDC’s Emergency Operations Center. As a Virologist she’s conducted doctoral and postdoctoral research on arboviruses including flaviviruses. Prior to CDC, Dr. Ottendorfer’s work experience included laboratory positions at the state public health reference laboratory at the Florida Department of Health for clinical laboratory testing and diagnosis of arboviral diseases.

Our second presenter is Dr. Matthew J. Binnicker with the American Society for Microbiology. Dr. Binnicker completed a fellowship at – in clinical microbiology at Mayo Clinic in Rochester Minnesota. He is currently the Director of Clinical Virology and an Associate Professor of Laboratory Medicine and Pathology at Mayo Clinic.

Our third presenter is Dr. Grace Kubin with the Association of Public Health Laboratories. Dr. Kubin has been the Director for the Texas State Public Health Laboratory since 2011. She has been involved with multiple disease outbreaks which required rapid increase in capacity such as the 2001 H1N1 pandemic, West Nile in 2012 and Ebola in 2014.

At this time please welcome Dr. Ottendorfer.

Dr. Christy Ottendorfer: Good afternoon everyone. My name is Christy Ottendorfer with the Centers for Disease Control and Prevention. And today’s presentation I’ll be covering the new guidance for U.S laboratories testing for Zika virus infection.

As CDC learns more about Zika virus CDC incorporates new information into its laboratory guidance for Zika virus so that we can refine and improve these assays.

During this call I have included some questions here for you to consider as a part of the new algorithms that have been developed. Approximately two weeks ago CDC issued an update to its guidance for US laboratories testing for Zika virus. This guidance expands the test parameters for CDC’s approved Trioplex RT-PCR assay as well as acknowledging other available commercial tests.

In addition the guidance document provides additional clarification for symptomatic patients and asymptomatic pregnant women with epidemiological criteria that should be tested, plus the appropriate testing algorithms. The full algorithms are located on the website noted here and will be covered in more detail by another presenter today.

As you may have experienced, laboratory diagnosis of Zika virus is complicated. There is often cross-reactivity with other circulating flaviviruses or prior yellow fever vaccination history in patients. This figure provides some background on why different tests and specimens are needed. Following exposure Zika virus RNA is the first detectable analyte in the blood. That’s shown in the first curve. Zika virus RT-PCR should be performed for specimens collected within 14 days after onset of symptoms. Urine and amniotic fluid can also be collected for this type of molecular test. As viremia declines the second detectable analyte, anti-Zika IgM antibodies, that are shown in the second curve, will rise. Serology assays are used to detect Zika virus specific IgM and neutralizing antibodies which typically develop towards the end of the first week of illness.

Of note IgM antibody levels also decline over time. As a result anti-Zika IgM antibodies can be detected up to 12 weeks after infection. Since these analytes rise and fall over time it's important to collect a paired serum to assist in diagnosis as antibody levels may remain elevated for a longer time period than the viral RNA. Finally as a reminder testing should be limited to specimens collected from individuals meeting CDC’s clinical and epidemiological criteria.

There are three assays that are commonly used to detect Zika virus, nucleic acid tests, which are also commonly called RT-PCR assays, are used to detect viral RNA. In addition there are two types of serological assays, the IgM ELISA and the plaque reduction neutralization test or PRNT. The Zika MAC-ELISA is used for presumptive detection of the Zika IgM antibodies and specimens that are positive on Zika MAC-ELISA are currently further analyzed using a plaque reduction neutralization test; however PRNT confirmation is not currently routinely recommended in Puerto Rico. And this is one of the updates to the laboratory guidance that was recently issued. The reason for this is there is a high prevalence of dengue virus and cross-reactivity in these tests in that area.

CDC developed the first two diagnostic assays for Zika virus that FDA issued an Emergency Use Authorization. The MAC-ELISA is used for presumptive detection of anti-Zika IgM antibodies, whereas CDC’s Trioplex RT-PCR can detect Zika, dengue and chikungunya viral RNA, which can distinguish from other viruses with similar clinical signs of Zika virus. These Trioplex test results can help inform important clinical and public health decisions as well as improve efficiency and throughput of laboratory testing. CDC's Zika diagnostic assays are distributed in the United States in the Laboratory Response Network, and have also been distributed internationally including over 1000 Trioplex RT-PCR kits to 115 countries.

The low level of viremia observed in some Zika virus cases poses a challenge for molecular testing. As a result, CDC continues to refine and improve its assays. Recently the FDA approved the addition of whole blood and analysis of larger sample volumes for CDC’s Trioplex assay. These updates were demonstrated to increase the sensitivity of the Trioplex assay and both methods may improve detection of low levels of viral RNA. Further, new laboratory instruments were approved that are commonly available in diagnostic laboratories.

This is an overview of other commercial assays that have been developed for Zika virus diagnostic testing. There are ten commercial diagnostic manufacturers that have received an FDA EUA for molecular test for Zika viral RNA. Recently all manufacturers with EUA molecular tests were requested to reassess individual test sensitivity using an FDA recommended reference panel.

The FDA reference panel contains RNA from two current Zika virus strains and three controls for blind testing. Test performance results of these assays will be published so that test performance can be compared among EUA manufacturers by laboratories nationwide. Besides the CDC Zika MAC-ELISA one commercial diagnostic manufacturer has received an EUA for serological test. Similar to the FDA reference panel mentioned above, three independent laboratories are also conducting performance evaluation of the available serological assays. These results will help inform future laboratory testing decisions. Three commercial laboratories have been licensed and are using CDC's Zika MAC-ELISA.

This is an overview of all of the nucleic acid-based EUAs that are approved for Zika virus testing. Note whole blood is approved for CDC Trioplex assay only. Please check with your laboratory prior to specimen collection as each EUA has specific requirements and which assays are available at that laboratory. Specific information on each FDA EUA is available at the website noted here and refer to the labeling section for further instructions.

This is an overview of the available IgM antibody test for Zika. Further CDC is meeting with states with high risk of local transmission. At this time the state of Texas has identified a potential case of local Zika virus transmission and CDC is supporting their investigation. Fortunately we have Dr. Kubin on the line today and she will be, I’m sure, have a lot of lessons or a lot of discussion of this topic and things that they’re learning at this time. In addition CDC works to ensure there is adequate laboratory capacity for potential testing demand and providing reagents to support the CDC developed assays for Zika virus. In closing, CDC recently issued updated laboratory guidance as we learn more about Zika virus infection and detection.

To improve sensitivity of the CDC Trioplex assay whole blood and analysis of larger sample volumes were added to the EUA. Serum must also be collected for serological testing. FDA has approved several EUAs for Zika virus clinical diagnostic testing as well so not only CDC developed assays. CDC will continue to monitor Zika virus disease and incorporate what is learned into its recommendations and guidance. Thank you for your attention.

Dr. Matthew Binnicker: All right, so this is Matt Binnicker. I’m the Director of Clinical Virology at Mayo Clinic and I want to thank everyone who's calling in today for this update on Zika virus testing. I also want to thank APHL, ASM, who I’m representing today, and the CDC for coordinating this important webinar and for inviting me to participate.

So the goal for my portion of the presentation will be to provide you with an update on the assays that are available to clinical laboratories for the diagnosis of Zika virus. And then we're going to highlight how we can use these tests. And we're going to do that by reviewing a series of case vignettes.

I think one of the things that we’ve come to recognize and appreciate since the beginning of the Zika virus outbreak is that our success at controlling this virus is going to require a team effort. It’s going to depend on careful coordination and cooperation among healthcare providers, public health, but also clinical laboratories. And I can’t stress enough that involvement of both local and private diagnostic laboratories will be essential in optimizing our ability to control this emerging viral threat and diagnose and manage our patients. And I think this is because the local laboratories are going to be closest to the patient, and can provide the most rapid and actionable results. And in addition, clinical labs must be involved and play an integral role so that we can reduce the burden of testing that’s placed on our public health labs, such as the CDC, during these outbreak settings.

Currently, as was reviewed during the first portion of the presentation, diagnostic assays for Zika, whether they be molecular or serologic, require emergency use authorization from the Food and Drug Administration prior to being used routinely. The CDC assays were the first to receive emergency use authorization, and as was discussed, include the Trioplex PCR and the MAC-ELISA serology test.

Trioplex detects Zika, dengue, and chikungunya viruses from a variety of different sample types. And according to the latest testing guidelines that were released recently, serum remains the preferred sample type but now whole blood and additional sample types can be submitted. But if they are [submitted], they should be accompanied by a paired serum sample. There have been some recent studies that have been published and shown that Zika virus may be shed in sample types such as urine and whole blood for longer periods of time. So those samples may be a good option if it’s been more than a week or 14 days since the patient had their onset of symptoms. Importantly, the Trioplex PCR assay is currently available only at the CDC and in select CDC designated public health labs. The MAC-ELISA assay is a serologic test, that detects IgM class antibodies from serum samples and at this time it is available only at the CDC but also at CDC designated public health labs, and also some designated reference laboratories.

Fortunately, as was reviewed earlier, there are now a number of commercial assays that received emergency use authorization and are available for detection of Zika nucleic acid or antibodies directed against the virus. The table on this slide is similar to the one that was shown earlier. It summarizes some of these commercial assays that have received EUA. The second column of the table summarizes the method that is used, for example, real-time RT-PCR or transcription mediated amplification, or in the case of the commercial assay that is approved for serologic testing, it utilizes an IgM Capture ELISA technique. The third column also shows the sample types that have received EUA for each of the respective assays. I should emphasize though that this is not going to be an all-inclusive list and that additional assays will likely become available in the coming months from various commercial companies.

So now that we have a better appreciation for the assays that are available to both public health and clinical laboratories for the diagnosis of Zika virus infection, I wanted to spend some time discussing how these tests should be used in the clinical setting. And we're going to do that by reviewing four short clinical cases.

So in the first case we have a 27-year-old female who has recently returned from vacation in Jamaica. And one week after arriving back home, the patient takes a pregnancy test, which is positive. However, the patient was well throughout the course of her trip and has not had any symptoms following her return so in her conversations with her primary care provider and her obstetrician, the question comes up, “Is Zika testing recommended in this patient, and if so, what type of testing should be performed?”

Due to this patient being pregnant and recently visiting an area where Zika virus transmission is occurring, diagnostic testing would be recommended in this case. A key factor in determining which type of testing should be performed is the amount of time that’s passed between the patient's return from travel or their last possible exposure, and when they present for evaluation. So if it’s been greater than 14 days since the patient returned from travel or had their last potential exposure then serologic testing is recommended, and that’s shown in the grayed out portion on the right-hand side of the algorithm on this slide.

However, if it’s been less than 14 days, as is the situation in this case, then it’s recommended to test a serum sample by an EUA approved PCR method for Zika virus. Urine and whole blood now may also be tested, but if they're submitted, they should be accompanied by a paired serum sample. So a positive PCR result in any of these specimen types would be diagnostic for Zika virus infection. And that's showed again grayed out on the left-hand side. But our patient, however, tested negative by PCR.

Now you might think that with a negative PCR result, we’d be done with testing in this case. But in pregnant females who test negative by PCR and are presenting less than 14 days after their last potential exposure, it’s recommended to collect a serum sample between that two and 12-week timeframe after their return from travel and that serum sample would then be tested for IgM class antibodies. And that’s because the period of positivity by PCR is very brief, as was highlighted with the figure earlier on during the presentation.

In our second case we have a 45-year-old gentleman from Honduras. And he visits his family in Texas. He indicates that he was well during the first seven days of his visit but has experienced an intermittent low grade fever, a rash, and mild joint pain over much of the past 2-1/2 weeks. So again the question comes up, “Is Zika testing indicated in this patient?”

So as we learned in the first case, one of the first pieces of information that we need to drive appropriate testing is determining the amount of time that’s passed between exposure or symptom onset. So in this case it’s been over two weeks since the patient developed symptoms, so the recommended approach would be to test a serum sample by Zika IgM serology. In addition, serologic testing for chikungunya and dengue virus would also be indicated since they can be circulating in that area and cause a very similar clinical presentation. Our patient tested positive for IgM class antibodies to Zika virus and results for dengue were interpreted as equivocal. In this situation, the serum sample should be tested by plaque reduction neutralization at CDC or a designated lab prior to confirming the diagnosis as Zika virus infection.

In our third case, we have a 57-year-old female who lives in Des Moines, Iowa. And she recently visited Haiti as part of a church mission trip. Two days after returning home, the patient contacts her primary care provider, and like most of us has seen a lot of information of Zika on the news, and so this patient is worried and requests testing for Zika. When asked whether the patient has been ill, the patient responds that she was well during her trip and remains asymptomatic but is worried about an exposure. So in this case, is testing recommended?

The current guidelines state that diagnostic testing is not recommended in asymptomatic non-pregnant individuals such as the patient in this case. One caveat that we need to consider is blood donors and potentially organ and/or tissue donors. On August 26 of this year, the US Food and Drug Administration recommended that all blood donated in the United States be screened for Zika virus using a molecular test. Currently there are several screening assays available, which use nucleic acid amplification technology. We definitely need more data to guide testing in this area, especially in regards to screening organ donors that have visited or reside in the Zika endemic region.

And our final case is of a 29-year-old female who has laboratory-confirmed Zika virus infection during the second trimester of her first pregnancy. And following delivery of her child, a clinical exam of the infant is performed which reveals no evidence of any physical abnormalities. So in this situation where we have an infant with no evidence of disease but that infant is born to a mother who had lab-confirmed Zika virus infection during pregnancy, is specific testing for Zika virus in the infant recommended?

So the answer in this case is, yes, lab testing would be recommended and it’s recommended for infants who are born to mothers with lab evidence of Zika infection. But in addition, testing is also indicated for infants with findings suggestive of congenital Zika who are born to mothers with an epidemiologic link. For example, did the mother travel to or live in an endemic region for Zika virus during pregnancy? So if those characteristics or features are met, initial testing of the infant should include Zika PCR of serum and urine, and as well, serology testing should be performed on the serum sample collected from the infant using an assay detecting IgM class antibodies to Zika virus.

The table on this slide provides a summary of how lab results should be used and interpreted when evaluating a patient for possible congenital Zika virus infection. So in the very first scenario, we have an infant with a positive PCR result on any sample type. And then regardless of the serology findings, if the PCR result is positive, this patient would be interpreted as a case of confirmed congenital Zika virus infection. For those infants that test negative by PCR but are positive for IgM class antibodies by serology, they would be considered to have probable congenital infection.

Finally, newborns testing negative by both PCR and IgM serology, as is going to be the case in the majority of the patients that we see, these individuals will be interpreted as negative for congenital Zika virus infection.

So to summarize this portion of the presentation, Zika virus poses a significant challenge to public health and clinical diagnostic labs. I’d reemphasize that a coordinated effort involving healthcare providers, clinical labs and public health will continue to be needed to identify cases and control the outbreak.

And finally, one thing that is certain is that this is going to continue to be an evolving process. We continue to learn more about the virus with each passing day and new data are going to continue to become available that will guide our diagnostic algorithms. So maintaining flexibility and focusing on good communication between the provider at the bedside and the clinical lab and then ultimately with our colleagues in public health will be keys to success in the future. So with that I'm going to pass the baton on to my colleague. Dr. Grace Kubin. who will provide you with some guidance and information from the perspective of the public health lab.

Dr. Grace Kubin: Hi. Good afternoon everyone or good morning wherever you may be located. Thanks very much to my colleagues on this webinar for giving such an excellent overview and discussion about Zika testing. I also would like to thank ASM and of course APHL who I’m representing on the call today for the opportunity to speak about this topic.

As Dr. Ottendorfer mentioned earlier this week we announced in Texas that we are investigating a Zika case that was probably caused by local transmission. So needless to say my colleagues here at the health department and everybody at the lab have been quite busy this week as well as a lot of our individuals out in the local health departments spent a good deal of their Thanksgiving holiday dealing with this too. So I want to thank our colleagues in Florida as well as Dr. Ottendorfer for all her help and assistance and insights as we're trying to work through all the issues that we’ve seen with this most recent case.

So I just kind of wanted to talk a little bit about some of the parallels that we saw with Zika and that we also kind of saw in the Ebola response. Ebola and Zika viruses were similar in that not much is known about them. Zika virus was first identified in the late 1940s but was not really seen in humans until the early 1950s. As you know, Ebola was not well-characterized. I think it was seen quite a bit earlier but still, not much was really known about it. And of course the first documented large-scale outbreak for Zika did not occur until 2007 which was on Yap Island. I’m sure many of you who are having to be involved in Zika response probably have heard quite a bit about that outbreak.

And we also really didn’t know much about how the virus performs in the body and other characteristics such as how long it might persist in the body and in what type of fluid, cells, or tissues. There was also a lot of confusion regarding testing and shipment of specimens. So initially, most commercial and private labs did not perform either the Ebola or Zika tests and providers were unfamiliar with how to get specimens to the public health laboratories who did do that testing. With a typical infectious disease I’m sure most of you are aware that usually the primary care providers are the ones who are most involved. But with both of these diseases we saw many different healthcare providers involved in the response. First responders, emergency department personnel, and individuals that were working with patients in isolation for the Ebola response. And for Zika OB/GYNs, neonatal personnel, and to steal a term from my Florida colleagues the baby catchers, so those individuals who really are involved with pregnancy and the - what happens after they, you know, provide, give birth.

So let’s talk a little bit about the actual testing. So you heard already on this webinar that there are many - there are several different types of tests that have been approved by the FDA for EUA. Public health laboratories have a lot of different types of test offerings. So some labs still perform what we call the PCR Singleplex assay. Of course many of the labs, public health labs, perform the Trioplex assay. And of course as Dr. Binnicker mentioned that’s only allowed for laboratories who are part of the Laboratory Response Network and approved by CDC.

Some of the public health labs or commercial labs perform both RT-PCR and serology, of which for the serology some of the labs might perform Zika only IgM and some also may perform chikungunya as well dengue IgM. And of course some labs will perform all three PCR, serology, and PRNT.

Of course needless to say these testing menus can be quite variable. That’s why I really encourage if you’re looking for testing to check the websites for each of the public health laboratories whether it's at the city, county, or state level and also for the commercial laboratories and private labs. And also you might want to familiarize yourself with the tests that are EUA approved. As mentioned detailed information about those assays can be found on the FDA medical device EUA website.

Okay so I’m probably going to sound a little bit like a broken record but individual websites are an excellent source for helping to know how much specimen to collect, how it should be stored if not sent right away, and under what type of conditions it should be sent whether it be either cold or frozen. You know, really the type of testing, what type of specimens that you are collecting and how you should ship them are really critical to ensuring that we're able to perform the tests that are needed for the patient. In addition our laboratory and many other labs are collecting additional information beyond the symptoms and the symptom onset date. This includes pregnancy status and at what point the patient is in during her pregnancy when she is getting testing or maybe has been exposed, the patient’s travel history (of course this is not necessarily an unfamiliar territory as we had to do this with Ebola). But then we’re also looking to have the travel history of any sexual partners. This information really is being used to determine at least in our health department as to what is the most appropriate testing for the patient.

Our epidemiologists spend a large amount of time, you know, having familiarized themselves with the algorithms and all of this extra information that we're collecting to really ensure that we in the lab are doing the tests that are most appropriate for that patient. In addition this information is also required if we end up having to submit specimens to CDC for additional testing.

So as mentioned previously serum is of course the preferred specimen type for RT-PCR. But depending on which type of test is being performed in the lab that you might be using or working with either whole blood, urine, or CSF could be submitted. But I will say that all three of these types of specimens will require a paired serum. So, you know, if you’re going to be sending us the urine, whole blood or CSF please also send a paired serum with that.

For this test, for RT-PCR a positive result is considered conclusive so really no additional testing is required. Under normal circumstances and what I kind of mean by that is not in the middle of a local transmission investigation and of course taking into account the lab’s capacity, PCR results could possibly be available two to three days from the time the specimen arrives in the laboratory. And of course this is a conservative estimate and it could be really a shorter or longer time really depending upon the lab's capacity and availability for testing.

So for serology specifically the MAC-ELISA serum of course is the only specimen type. The MAC-ELISA really is a multi-day test and results may be available three to four days after arrival in the lab. Again that’s kind of a conservative estimate based on capacity of the lab. And this test is of course used by most of the public health laboratories and as mentioned, you know, any positive or clinical results for Zika IgM will require confirmation by the PRNT. And of course depending upon where the patient may have been infected we will usually perform also dengue and chikungunya serology.

So for PRNT of course, you know, again, serum is the preferred specimen. And only CDC or CDC approved labs will perform this test. Really the results of the PRNT must be interpreted in the context of the serology results again which probably should include either a dengue or chikungunya IgM result depending upon where the patient might have been infected. This test really requires more time for completion because the basis for interpretation is whether or not neutralizing antibodies that are specific to Zika or the other flaviviruses probably either West Nile or dengue or chikungunya are present and will basically inhibit virus growth. Thus virus must have an opportunity to grow so that means it’s going to take a little bit of time for the test to be completed. This is of course a really gross simplification of what the assay is but hopefully I was able to kind of at least let you all know that this is some of the reason why it can take quite some time for the results to come back. Of course there are other factors that could delay the results.

We, in our lab, pretty much only ship to CDC Monday through Thursday. So if we get a result on Friday it’s got to wait until probably Monday for us to ship it out. So that can delay a couple of days right there. So and also it will depend upon, you know, what’s going on at CDC if they’ve had a large influx of requests for PRNT.

They’ve actually done an excellent job of being able to prioritize these samples and getting them out really quickly as fast as they can. But, you know, don’t be surprised if it might take a couple of weeks for you to get these particular test results back. And so if you think about well I submitted my sample at the beginning of November you may not see something until closer to the end of November if we had to go through during both PCR - all three, PCR serology and PRNT. So keep in mind that that just adds a lot more time onto the actual testing time.

So I’d also like to talk a little bit about some of our partners that we’ve hooked up with not only at the public health level but also at the health department level. And of course many of these when I talk about public health labs I'm talking about state, I'm talking about local maybe [city or] county health departments also are intimately involved in a lot of this. We’ve actually been pretty fortunate to have some of our private labs contact us and let us know that they’ve brought up RT-PCR testing capacity and have offered to assist us with testing if our lab becomes a little bit overwhelmed for testing.

We're actually pretty fortunate in Texas because we have multiple CDC Laboratory Response Network labs. We have actually ten including ours. And they all are doing some sort or a form of Zika testing. So we have some – we're pretty lucky that we have some actual built in capacity. And one thing that we did do this week as we were receiving uro [urine] specimens uro survey specimens in is we actually kind of divided it up some of the specimen load and we were able to ship samples to some of these other laboratories so that we could kind of basically get the results back maybe a little bit faster.

In addition we’ve actually been in contact with several commercial labs and they are working with a lot of their public health laboratories in their states and cities to be ready to provide surge capacity testing in case there is something like what happened, a large-scale investigation. But what was very helpful about these laboratories and I think Dr. Binnicker mentioned this in his presentation is that, you know, these labs can provide the ability to collect specimens in maybe some of the lower population areas where resources may be very limited for obtaining testing. You know, we see a lot of these commercial labs they do have basically draw stations in some of our smaller communities so it really it is helpful to have them available to kind of work with us and also be a surge capacity for us in the event that we might need them.

And I guess we also have several military bases in the state of Texas who have also implemented both Zika RT-PCR and IgM testing. And, you know, they stand of course ready to assist us and provide surge capacity in case we might need it. And of course, you know, CDC is the main provider for PRNT in the states. But they also have a separate lab that’s been set up to help with specifically with local transmission and investigations.

So I just want to spend a little bit of time last thing on talking about the efforts related to education and outreach for Zika virus and response activities associated with cases that we’ve had. We had a large media campaign, and other states are doing this too, where public service announcements maybe on radio or TV maybe in multiple languages and have really tried to use social media sites to really allow us to reach a much broader audience.

Many health departments whether they're state or local or county are working with local healthcare personnel. Many of the epidemiologists in these health departments, you know, they work for closely with providers and they actually have a lot of interactions with them. And of course at the state level one of the things that we’ve tried to do is have meetings and webinars with a variety of healthcare provider associations. And some of those in our state of course are Texas State Medical Association, [Texas] Pediatric Society that we have here, also the OB/GYN Association that we have here and our Texas Hospital Association. We have developed really good relationships with all of these different groups. And we’ve had the opportunity to meet with them on several occasions and also been invited to speak at some of their regular meetings.

We also used WIC (which is the Women's Infants and Children) sites for distribution of pamphlets and posting education materials. This has been very useful for us. We’ve also had the opportunity, our state Medicaid group has been really very good about getting out information to providers who are Medicaid providers. And, you know, we do have several things and I don’t actually have this in my presentation of lessons learned about what’s been occurring this week. You know, what we found is that our local health departments, you know, their staff, their epidemiologists, you know, they’ve been working these cases now for many months in some cases almost a year. And they really know how to interact with their providers. They’ve been invaluable in ensuring that if a provider has a question they're really kind of Johnny on the spot with information about how to collect, what to collect, what types of forms should be filled out and also some assistance in how they should be shipping the specimens. I think their ability to really interact on a very intimate level with the providers has helped us at the public health labs be really successful in getting specimens here to us in a manner by which we can test them. And, you know, so I really want to say that, you know, this has really been, this response and what’s been going on with Zika has really been an all-hands response.

Laboratories, epidemiologists, all the different types of providers and providers that we're really not used to working with at the public health labs because they’re not used to sending us these types of clinical specimens because they might use a private or commercial lab. So I think all of these individuals working together has really been and Dr. Binnicker mentioned this too a real - it's a team effort to make sure that we're getting the testing done. I think as we move forward in the long term one thing we will have to look at is, you know, how will we be treating Zika in the future? So I think with all of the testing that we're doing the additional data that’s being collected that will help guide us in where we need to go with that. So anyway I want to thank everybody for joining the call today and thanks for your attention. With that I’ll turn it back over to Will Koehne.

William Koehne: Thank you. Thank you presenters for providing our audience with a wealth of information. We're now going to open up the lines for a question and answer session. Questions are limited to clinicians who would like information related to Zika virus testing and laboratories. For those who have media questions please contact CDC Media Relations at 404-639-3286 or send an email to media@cdc.gov.

If you are patient please refer your questions to your healthcare provider. When asking questions please state your organization and also remember that you can submit questions through the webinar system. Operator if you’d like to open up the phone lines, we have a few webinar questions that I’d like to go through before we get to the phone Q&A.

But, the first one is from (Mary Anderson). She’s asking, 'When submitting for whole blood testing what is the preferred anticoagulant?" And she is also asking for a specific tube collar.

Dr. Grace Kubin: Hi. This is Grace Kubin. I’ll be happy to answer that information. So when you’re submitting whole blood for the basically for the Trioplex assay it is a purple top tube with EDTA.

William Koehne: All right thank you Grace. We have another one from (Southern Sumason) asking, "What is the appropriate time window to test an infant with suspected Zika?" So would – I know Matt Binnicker, Dr. Binnicker presented on that. Would you like to elaborate a little bit on that?

Dr. Matthew Binnicker: Yes. I believe it’s within the first two days of life is what’s listed on the CDC website but I want to make sure that Dr. Ottendorfer for confirms that.

Dr. Christy Ottendorfer: I would concur with the two days. There is some in the algorithm that if there's a possibility that they could be screened at 18 months if, to ensure the maternal antibodies have declined. So there's a possibility they could be detecting maternal antibodies and not the infant’s and so they would need to be screened at a later point. And I’d refer back to the algorithm. I would like to note here that there’s been a recent study that’s been released about microcephaly that wasn’t, or brain abnormalities, that weren't detected at birth but they were detected six monrto a year up to a year later. And so as we learn more about this type of, you know, new clinical manifestation I guess there may be updated guidance on how to test infants going forward.

William Koehne: Thank you. Operator do we want to – can we take a question from the phone lines?

Coordinator: Thank you. We'll now begin the question and answer session at this time over the phone. If you would like to ask a question please press Star 1, unmute your phone and record your name clearly. When you ask your question please announce your organization. Your name is required to introduce your question. If you need to withdraw that question press Star 2. Again to ask a question please press Star 1. The first question comes from (Frederick Walters). Your line is open sir.

Frederick Walters: So hi. I had a question in regards to the CC MAC-ELISA test. Have you guys seen any trends with inconclusive results because we have certain samples that the result is inconclusive. And we'll re-collect two to four weeks later that it will come back inconclusive again. Have you guys seen anything like that?

Dr. Christy Ottendorfer: So from CDC we're actually in the Emergency Operations Center. I would defer that question for a follow-up with our actual laboratory teams either in Fort Collins or here in Atlanta. We are looking at the test results to see sort of the person at the do confirm and we'll be happy to share that information with you if we have your contact information.

William Koehne: And this is Will Koehne, William Koehne with CDC as well. If you’d like to if there’s any questions that we're unable to answer on the call today or that we're unable to get to please feel free to send them to coca@cdc.gov that’s C-O-C-A@cdc.G-O-V and we'll forward that on to the correct parties and get you an answer.

Frederick Walters: Okay thank you.

William Koehne: Are any other speakers or would you like to address that question? Okay operator are there any other questions on the phone line?

Coordinator: There are. The next question comes from I believe it was (Ana Disamuels). Your line is open.

Ana Disamuels: Hi. Good afternoon. We're logging in from Johns Hopkins Pediatrics. Our question is regarding negative testing in an infant whose mother had confirmed Zika virus during pregnancy. The infant in this case would have - does have abnormalities consistent with congenital Zika syndrome without any other explanations. However the testing both PCR and serologies are negative.

Our concern is that if the infection in the mother occurred during the first trimester that negative serologies may not exclude congenital infection. Are there any other thoughts about the interpretation of negative serology in this type of situation?

Dr. Christy Ottendorfer: That is an excellent question. And we may defer this to our pregnancy and birth defects groups that handles more of the trimester and, you know, those results and how you should interpret these assays. Like we’ve mentioned the timing is critical when those specimens are collected. I’m not sure how old the infant was upon – has it had follow-up testing or it was just tested at the two day point?

Ana Disamuels: Just at the newborn time period. However the serologies were repeated as they were initially inconclusive so repeat sampling was sent from the serum again. That ended up being negative.

Dr. Christy Ottendorfer: I think this is something that for this particular case we might try to get you in contact with our pregnancy and birth defects team to try to help you understand if there is another potential cause or how to follow up with this patient.

Ana Disamuels: Thank you.

Coordinator: The next question on the phone line comes from Dr. Hudson. Your line is open sir.

Dr. Warner Hudson: Thank you. This is Warner Hudson from UCLA. I’m in charge of occupation employee health here for the health system on campus. We have a lot of travelers coming back from Zika areas, researchers in Zika area,s and live Zika research work in our labs. And most of the UC-wide Doc Med medical writers have been working on developing post-exposure protocols for the labs. And of course we’re doing testing for the travelers that come back with questions or symptoms. And at UCLA we're using the Viracore test but the PCR tests and the IgM tests. Does CDC have a plan to put together post-exposure guidelines for lab workers, even blood-borne exposures to viremic Zika patients in the works? Thanks.

Dr. Christy Ottendorfer: That is another excellent question. I know that this guidance that was released predominantly focuses on symptomatic individuals as well as, you know, pregnant women that, you know, those that are highest risk for, you know, complications from Zika infection for the infants. So I’m not sure if there is guidance planned for, you know, more of the occupational exposure risks that may occur in otherwise, you know, healthy adults but we will certainly take that into consideration and bring it back to the leadership as a request.

Dr. Warner Hudson: Alright thank you.

William Koehne: So we have a question from the Webinar system that I’d like to ask quick. We have - the question is we have encountered several mothers with history who travel to Zika endemic areas longer than 12 weeks ago. Testing has been negative. Newborns are healthy at birth. What – they’re asking what role of IgG to document earlier exposure to the virus? What is the role of IgG to document earlier exposure to the virus?

Dr. Christy Ottendorfer: So I guess I’ll take this one too. As far as IgG we don’t have a specific assay for IgG, the plaque reduction neutralization test for once the neutralizing antibodies develop which in my slide I didn’t show that part of the course of illness or your, you know, your antibody response. But at some point in that window IgG begins to rise longer than 12 weeks. And so if you were to have that sample tested it would probably be tested in plaque reduction neutralization and it could be possible to detect a infection in that sample. But I would defer to Grace or anyone else that has more experience with samples collected after 12 weeks.

Dr. Grace Kubin: Hi. This is Grace Kubin. We don’t we haven’t really typically tested or have been sent very many samples after 12 weeks. I do know a few labs that have but they don’t - some have seen a positive and some haven't so, you know, it’s basically just a byproduct of how good a person's immune system is.

Dr. Christy Ottendorfer: Right and I would agree. I mean if we're testing the infant here you’ll have maternal antibodies until about 18 months so it could be confounded by the mother’s antibodies or IgG at that point. So you would want to retest if you have either clinical or epidemiological criteria for this infant at 18 months.

William Koehne: All right thank you presenters. I think that’s all the time that we have for questions today. And on behalf of COCA we would like to thank everyone for joining us today with a special thank you to our presenters Drs. Ottendorfer, Binnicker and Kubin. And please feel free to contact the presenters after the call by emailing COCA at cdc.gov that’s C-O-C-A@cdc.G-O-V.

The recording of this call and the transcript will be posted to the COCA website at emergency.cdc.gov/coca within the next few days.

We have two upcoming COCA calls next week. On Tuesday, December 6 at 2:00 PM Eastern Time please make sure to join us for “Risk Mitigation Strategies to Reduce Opioid Overdoses,” part of a COCA call series about the CDC Guideline for Prescribing Opioids for Chronic Pain.

In addition, please join us next week Thursday, December 8 at 2:00 PM Eastern time for another COCA call on Zika. This one is called “Gearing Up for the Travel Season, How Clinicians Can Ensure their Patients are Packed with Knowledge on Zika Prevention.” And we have speakers from CDC pregnancy and birth defects and CDC Zika Travelers Health presenting for that call.

All continuing education for the COCA calls are issued through the TCEO online the CDC Training and Continuing Education system at www.cdc.gov/tceonline. Those who have participated in today’s COCA call and would like to receive continuing education should complete the online evaluation by December 31, 2016 and use the course code WC2286. Those who would – who will review the call on demand and would like to receive continuing education should complete the online evaluation between January 1, 2016 and November 30, 2018 and they will use the course code WD2286.

To receive information about these upcoming COCA calls please subscribe to COCA by going to the COCA webpage at emergency.CDC.gov/coca and clicking on the joint COCA mailing list link. Also CDC has launched a Facebook for clinicians. Like our page at Facebook.com/cdcclinicianoutreachandcommunicationactivity to stay connected to the latest news from COCA. Thank you again everyone for being part of today’s COCA call. Have a great day.

Coordinator: That concludes today’s conference. Thank you for your participation. You may disconnect at this time. Speakers please stand by for your post conference.

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