Human illness caused by Asian lineage A(H7N9) virus infection is an acute infectious disease. Patients may experience prolonged virus replication and viral shedding, especially if they are immunosuppressed, and their hospital course may last up to 3 weeks or longer after disease onset. Once surviving patients have clinically improved and have been discharged, they may have immunity to subsequent infection by antigenically similar A(H7N9) virus strains, or decreased likelihood of severe illness if re-infected.
Long-term sequelae of acute respiratory distress syndrome include neuromuscular weakness, diminished lung function, post-traumatic stress disorder, and cognitive decline in older patients. A cohort study of 56 A(H7N9) patients who survived hospitalisation reported that although pulmonary function and chest computed tomography scan findings had improved by 6 months, most patients had persistent abnormalities 2 years after hospital discharge.
The World Health Organization recommends close observation and post-exposure oseltamivir or zanamivir chemoprophylaxis for healthcare workers after unprotected close exposure to a symptomatic, suspected, or confirmed Asian lineage A(H7N9) case (within 2 m) in the healthcare setting, as well as for household and close contacts of a patient with suspected or confirmed Asian lineage A(H7N9) virus infection.
Suspected cases should be reported to public health authorities, who will assist with diagnostic evaluation, case management, and contact investigations. CDC: information on avian influenza external link opens in a new window Public Health England: avian influenza - guidance, data and analysis external link opens in a new window
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