CDC Recommendations for the Amount of Time Persons with Influenza-Like Illness Should be Away from Others

October 23, 2009

CDC recommends that people with influenza-like illness remain at home until at least 24 hours after they are free of fever (100° F [37.8°C]), or signs of a fever without the use of fever-reducing medications.

This is a change from the previous recommendation that ill persons stay home for 7 days after illness onset or until 24 hours after the resolution of symptoms, whichever was longer. The new recommendation applies to camps, schools, businesses, mass gatherings, and other community settings where the majority of people are not at increased risk for influenza complications. This guidance does not apply to health care settings where the exclusion period should be continued for 7 days from symptom onset or until the resolution of symptoms, whichever is longer; see Guidelines for infection control for updates about the health care setting. This revision for the community setting is based on epidemiologic data about the overall risk of severe illness and death and attempts to balance the risks of severe illness from influenza and the potential benefits of decreasing transmission through the exclusion of ill persons with the goal of minimizing social disruption. This guidance will continue to be updated as more information becomes available.

Decisions about extending the exclusion period should be made at the community level, in conjunction with local and state health officials. More stringent guidelines and longer periods of exclusion – for example, until complete resolution of all symptoms – may be considered for people returning to a setting where high numbers of high-risk people may be exposed, such as a camp for children with asthma or a child care facility for children younger than 5 years old. High-risk groups for influenza complications include: children younger than 5 years old; persons aged 65 years or older; children and adolescents (younger than 18 years) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye syndrome after influenza virus infection; pregnant women; adults and children who have asthma, other chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders such as diabetes; adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV); and residents of nursing homes and other chronic-care facilities.

Epidemiologic data collected during spring 2009 found that most people with the 2009 H1N1 influenza virus who were not hospitalized had a fever that lasted 2 to 4 days; this would require an exclusion period of 3 to 5 days in most cases. Those with more severe illness are likely to have a fever for longer periods of time. Although fever is a component of the case definition of influenza-like illness, the epidemiologic data collected during spring 2009 found that a minority of patients infected with the 2009 H1N1 influenza virus with respiratory symptoms did not have a fever.

Sick individuals should stay at home until the end of the exclusion period, to the extent possible, except when necessary to seek required medical care. Sick individuals should avoid contact with others. Keeping people with a fever at home may reduce the number of people who get infected, since elevated temperature is associated with increased shedding of influenza virus. CDC recommends this exclusion period regardless of whether or not antiviral medications are used. People on antiviral treatment may shed influenza viruses that are resistant to antiviral medications.

Many people with influenza illness will continue shedding influenza virus 24 hours after their fevers go away, but at lower levels than during their fever. Shedding of influenza virus, as detected by RT-PCR, can be detected for 10 days or more in some cases. Therefore, when people who have had influenza-like illness return to work, school, or other community settings they should continue to practice good respiratory etiquette and hand hygiene and avoid close contact with people they know to be at increased risk of influenza-related complications. Because some people may shed influenza virus before they feel ill, and because some people with influenza will not have a fever, it is important that all people cover their cough and wash hands often. To lessen the chance of spreading influenza viruses that are resistant to antiviral medications, adherence to good respiratory etiquette and hand hygiene is as important for people taking antiviral medications as it is for others.

Fever-reducing medications, that is, medications containing acetaminophen or ibuprofen, are appropriate for use in individuals with influenza-like illness. Aspirin (acetylsalicylic acid) should not be given to children or teenagers who have influenza; this can cause a rare but serious illness called Reye’s syndrome. The determination of readiness to return to school, businesses, or other community settings should be made when at least 24 hours have passed since the ill person’s temperature first remained normal without the use of these medications.

Visit: HomeCare Guidance for more information on caring for sick persons in the home.