H3n2 Influenza Virus

During the 2021-2022 influenza season, vaccination significantly reduced outpatient visits, consistent with prior seasons during which A(H3N2) viruses were predominant, especially among younger patients, recent study data showed.

Influenza reached epidemic levels in Chile months earlier than a typical influenza season, just like in several other Southern Hemisphere countries, researchers reported.

Interim estimates published Thursday in MMWR indicate that this season’s influenza vaccine has not been effective.

According to the CDC, influenza activity this season has been “unusually low,” with rates of hospitalization as of late January that were similar to 2011-2012 — the least severe season in the past decade.

More evidence indicated that mutations introduced by egg-based production led to a decrease in influenza vaccine efficacy during the severe 2017-2018 influenza season, researchers reported in The Journal of Infectious Diseases.

Hospitals in the United States implemented new policies based on the severe 2017-2018 influenza season, but experts agree that America’s health care systems would still be seriously challenged by another bad season.

WASHINGTON — Cell- and egg-based quadrivalent inactivated influenza vaccines have comparable immunogenicity for children aged 4 years and older, according to results from a randomized controlled trial presented at IDWeek.

A recent report published in Emerging Infectious Diseases detailed a case of likely human-to-human transmission of an influenza A virus with reduced susceptibility to Xofluza between two siblings in Japan.

Xofluza significantly reduced the risk for influenza infection among children aged younger than 12 years and adults living with infected individuals by 86%, according to phase 3 trial findings released by Genentech.