Primary prevention

The optimal means of containing Asian lineage A(H7N9) virus in communities and decreasing the risk to human health is unknown. However, the closure of live markets in affected areas, with prompt culling of poultry with Asian lineage A(H7N9) virus infection and disinfection of the contaminated environment, may help to contain outbreaks and disrupt zoonotic transmission. Vaccination of poultry with an H5/H7 vaccine was correlated with a decline in detection of A(H7N9) viruses in vaccinated poultry and environmental specimens, and sharp reduction in human infections.[57][58] The most effective way to prevent Asian lineage A(H7N9) virus infection of people is to minimize exposure to infected poultry. Unlike highly pathogenic avian influenza (HPAI) A(H5N1) virus infection, Asian lineage low-pathogenic avian influenza (LPAI) A(H7N9) virus infection causes asymptomatic or subclinical infection in poultry, making it impossible to identify infected poultry without laboratory testing. Asian lineage HPAI A(H7N9) virus has not yet replaced the LPAI virus, but if it does, outbreaks in poultry will be easier to detect.

The WHO and national public health agencies do not recommend travel restrictions to Asian lineage A(H7N9) virus-affected countries. It is recommended, however, that people avoid contact with poultry suspected of Asian lineage A(H7N9) virus infection, avoid animals in live food markets where an active Asian lineage A(H7N9) virus outbreak is occurring in poultry, and avoid contact with any surfaces that may be contaminated by feces from poultry or other animals suspected of having Asian lineage A(H7N9) virus infection.

Currently, no vaccine is licensed to prevent Asian lineage A(H7N9) virus infections in humans. The WHO and partners are working on vaccine development, including tests of safety and immunogenicity, as part of pandemic preparedness plans. Healthcare workers are recommended to receive annual seasonal influenza vaccine to decrease the risk of nosocomial transmission of seasonal influenza viruses in the healthcare setting. Preventing seasonal influenza among people exposed to Asian lineage A(H7N9) virus may also decrease the theoretical risk of human coinfection with seasonal influenza A and Asian lineage A(H7N9) viruses and the associated risk of viral reassortment (an event that could lead to the emergence of a potential pandemic influenza A virus strain).

Most public health agencies consider the use of oral oseltamivir or inhaled zanamivir as antiviral chemoprophylaxis for primary prevention (pre-exposure prophylaxis) to be unnecessary if appropriate personal protective equipment and infection control precautions are followed. Some public health agencies may recommend pre-exposure prophylaxis in select individuals who are involved in responding to avian influenza virus outbreaks in birds.

WHO: FAQs on human infection caused by the avian influenza A(H7N9) virus

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