Recommendations and Reports TABLE 10. Recommended nonpharmaceutical interventions for influenza pandemics, by setting and pandemic severity* Pandemic severity Low to moderate severity High severity Very high severity † Setting (mild to moderate pandemic) (severe pandemic) (very severe to extreme pandemic ) All CDC recommends voluntary home CDC recommends voluntary home CDC recommends voluntary home isolation of ill isolation of ill persons, respiratory isolation of ill persons, respiratory persons, respiratory etiquette, hand hygiene, and etiquette, hand hygiene, and etiquette hand hygiene, and routine routine cleaning of frequently touched surfaces routine cleaning of frequently cleaning of frequently touched and objects. § touched surfaces and objects. surfaces and objects. Residences CDC generally does not recommend CDC might recommend voluntary CDC might recommend voluntary home voluntary home quarantine of home quarantine of exposed quarantine of exposed household members in exposed household members. household members in areas where areas where novel influenza virus circulates. novel influenza virus circulates. CDC generally does not recommend CDC might recommend use of face CDC might recommend use of face masks by ill use of face masks by ill persons. masks by ill persons when crowded persons when crowded community settings community settings cannot be avoided. cannot be avoided. Child care facilities, schools for CDC might recommend selective CDC might recommend temporary CDC might recommend temporary preemptive, grades K–12, and colleges school dismissals in facilities serving preemptive, coordinated dismissals coordinated dismissals of child care facilities and universities children at high risk for severe of child care facilities and schools.¶ and schools. influenza complications. If schools remain open, CDC might If schools remain open, CDC might recommend recommend social distancing social distancing measures. measures.** Workplaces CDC generally does not recommend CDC might recommend social CDC might recommend social distancing measures. social distancing measures. distancing measures.†† Mass gatherings§§ CDC generally does not recommend CDC might recommend modifications, CDC might recommend modifications, modifications, postponements, or postponements, or cancellations. postponements, or cancellations. cancellations. Abbreviation: NPI = nonpharmaceutical intervention. * Personal, community, and environmental NPIs should be 1) initiated early in a pandemic before local epidemics begin to grow exponentially, 2) targeted toward the nexus of transmission (in affected areas where the novel virus circulates), and 3) layered together to reduce community transmission to the greatest extent possible. † During a very severe or extreme pandemic (similar to the 1918 pandemic), CDC is likely to take an aggressive stance and recommend certain additional NPIs. § Recommended NPIs are the same for seasonal influenza. ¶ Preemptive, coordinated dismissals might be implemented early during a pandemic to decrease the spread of influenza before many students and staff members become ill. Selective dismissals might be implemented by schools that serve students at high risk for complications from infection with influenza. Reactive dismissals might be implemented when many students and staff members are ill and not attending school or when many students and staff members are arriving at school ill and being sent home. Selective and reactive dismissals do not help slow disease transmission in the community. ** Social distancing measures that reduce face-to-face contact in schools might include dividing classes into smaller groups of students who are spaced further apart from each other within the classroom. †† Social distancing measures that reduce face-to-face contact in workplaces might include offering telework and remote meeting options. Flexible sick leave policies should be implemented to encourage workers to stay home if needed. §§ In all scenarios, mass gathering attendance during local outbreaks should be discouraged for persons at high risk for severe influenza-related complications. 32 MMWR / April 21, 2017 / Vol. 66 / No. 1 US Department of Health and Human Services/Centers for Disease Control and Prevention