Five virus families that could cause the next pandemic – University of Sydney

Before COVID-19, influenza was the infection mostwell-knownfor causing pandemics.

Influenza virus is subdivided into types (A, B, and rarely C and D). Influenza A is further classified into subtypes based on haemagglutinin (H) and neuraminidase (N) protein variants on the surface of the virus. Currently, the most common influenza strains in humans are A/H1N1 and A/H3N2.

Zoonotic infectionoccurs when influenza strains that primarily affect animals spill over to humans.

Major changes in the influenza virus usually result fromnew combinationsof influenza viruses that affect birds, pigs and humans. New strains have the potential to cause pandemics as there is little pre-existing immunity.

Since the beginning of the 20th century, there have been four influenzapandemics, in 1918, 1957, 1968, and 2009. In between pandemics, seasonal influenza circulates throughout the world.

Although influenza is not as infectious as many other respiratory infections, the very short incubation period of around 1.4 days means outbreaks can spread quickly.

Vaccines are available to prevent influenza, but are onlypartiallyprotective. Antiviral treatments are available, including oseltamivir, zanamivir, peramivir and baloxavir. Oseltamivirdecreasesthe duration of illness by around 24 hours if started early, but whether it reduces the risk of severe influenza and its complications iscontroversial.

Allen Cheng

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Five virus families that could cause the next pandemic - University of Sydney