[WHO clinical practice guidelines for influenza: an update]

Every year, more than one billion people around the world are infected with influenza, an acute infection of the respiratory tract. Influenza spreads from person to person through air, contaminated hands or objects. Antiviral and immunomodulatory drugs are available for treatment of patients and prophylaxis of exposed persons. Reverse transcription polymerase chain reaction (RT-PCR), nucleic acid amplification tests (NAATs) and rapid tests are available for the diagnosis of influenza. Objective The aim of this World Health Organization (WHO) guideline is to provide recommendations for the diagnosis, drug treatment and prophylaxis of influenza.This updated guideline has been developed in accordance with standards for trustworthy guidelines. The recommendations are based on systematic reviews on safety and effectiveness. They take into account the magnitude of benefits and harms of treatments, the reliability of the evidence, and the needs of patients and healthcare professionals.For non-severe influenza, there is a conditional recommendation to use baloxavir if the risk of severe illness is high. Antivirals are not recommended if the risk is low. There is also a strong recommendation against the use of antibiotics if bacterial co-infection is unlikely. Oseltamivir is conditionally recommended for severe influenza. Not recommended are peramivir and zanamivir, as well as macrolide antibiotics (in the absence of co-infection), mTOR inhibitors and plasma therapy, and corticosteroids. Baloxavir and oseltamivir are conditionally recommended for prophylaxis in asymptomatic persons who have been exposed to seasonal influenza viruses and would be at very high risk of becoming hospitalised. For zoonotic influenza, laninamivir and zanamivir are also conditionally recommended in addition to baloxavir and oseltamivir, regardless of individual risk. For diagnosis, the use of NAAT or digital immunoassay (DIA) for suspected non-severe influenza and nucleic acid amplification test (NAAT) for suspected severe influenza is recommended.