MMWR News Synopsis for January 15, 2015

Updated Estimates of Neural Tube Defect Prevalence at Birth Before and After Mandatory Folic Acid Fortification — United States, 1995–2011

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Even with the success of folic acid fortification, we can do more. Public health interventions targeting women with lower folic acid intake, especially Hispanic women, might help reduce neural tube defect prevalence even further. The prevalence of neural tube defects (NTDs) has decreased by 35 percent since folic acid fortification in the United States, which translates to about 1,300 babies born NTD-free annually because of this intervention. NTDs are serious birth defects of the brain or spine. Since 1998, enriched grain products in the U.S. have been fortified with folic acid to prevent NTDs. Even with fortification, some women do not get enough folic acid. CDC urges all women of child bearing age, whether planning a pregnancy or not, to get 400 mcg of folic acid daily from fortified foods, supplements, or both, in addition to consuming folate-rich foods from a varied diet. Getting the recommended amount of folic acid is an important way to help prevent these serious birth defects.

Supplement Use and Other Characteristics Among Pregnant Women with a Previous Neural Tube Defect–Affected Pregnancy — United States, 1997–2009

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Many women who have had a pregnancy affected by a neural tube defect (NTD) and are planning another pregnancy are not following folic acid supplement recommendations. Healthcare providers should strengthen their message to these women to encourage folic acid use. Among women with a previous pregnancy affected by a neural tube defect (NTD), women who had a second pregnancy affected by an NTD reported taking folic acid less often (35%) than those who had a baby without a birth defect (80%). Women who have had a pregnancy affected by a NTD are at an increased risk for having another pregnancy affected by an NTD. High-dosage folic acid supplements — 4.0 mg per day taken at least 4 weeks before becoming pregnant through the first 12 weeks of pregnancy — are known to reduce the risk of a NTD.

Influenza Vaccine Effectiveness, 2014–15 Season

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CDC continues to recommend influenza vaccination even when vaccine effectiveness is reduced because the vaccine can still prevent some infections by the circulating A (H3N2) viruses as well as by other viruses that may circulate later in the season, including influenza B viruses. Even when vaccine effectiveness is reduced, vaccination prevents thousands of hospitalizations and deaths. While vaccination should continue as long as influenza viruses are circulating, treatment with “anti-flu” drugs is more important than usual. All hospitalized patients and all outpatients at high risk of serious complications from influenza should be treated as soon as possible with one of three available influenza antiviral medications if flu is suspected. Early estimates indicate that influenza vaccines provide limited protection against influenza viruses circulating during the first part of the 2014-15 season, which were mainly influenza A H3N2 viruses. Based on data from 2,321 children and adults with acute respiratory illness enrolled during November 10, 2014–January 2, 2015, at five study sites with outpatient medical facilities in the United States, the overall estimated effectiveness of the 2014–15 seasonal influenza vaccine for preventing medically attended, laboratory-confirmed influenza virus infection was 23%. Effectiveness of seasonal influenza vaccine can vary and depends in part on the match between vaccine viruses and circulating influenza viruses. So far this season, more than two-thirds of influenza A(H3N2) viruses are different from the H3N2 component of 2014-15 influenza vaccine. Influenza vaccination, even with reduced effectiveness, prevents thousands of hospitalizations in moderate or severe influenza seasons like the present one.

Incidence of Notifiable Diseases Among American Indians/Alaska Natives — United States, 2007–2011

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State and local health departments with large American Indian/Alaska Native (AI/AN) populations in their jurisdictions can work with Tribal officials and communities in using surveillance data to develop and implement effective interventions that reduce the excess burden of infectious diseases in AI/AN populations. AI/AN populations experienced higher rates of new infections than non-Hispanic white (NHW) populations for 14 of 26 reportable infectious diseases during 2007-2011. Although incidence rates of some infectious diseases have declined in AI/AN populations, disparities between groups remain. CDC analyzed data from the National Notifiable Diseases Surveillance System (NNDSS) that collects reports on nationally notifiable diseases in the United States and its territories. Interventions are needed to  reduce disparities in chlamydia, gonorrhea, West Nile virus, spotted fever rickettsiosis, and other infections between AI/AN and NHW populations.

Notes from the Field: 

Outbreak of Diarrheal Illness Caused by Shigella flexneri — American Samoa, May–June 2014

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES