GlobalHealth Threats

In the latest Morbidity & Mortality Weekly Report (MMWR), the Centers for Disease Control & Prevention (CDC) highlight the atypical influenza season and prompt doctors to consider flu as a likely cause of respiratory symptoms even though the typical winter flu season may be months away. In reviewing the 2021-22 influenza season, social distancing and other measures designed to combat the COVID-19 pandemic likely resulted in lower levels of flu activity than might otherwise have been expected. However, the flu season started later (November vs October) and was much longer than usual with two peaks in February and April 2022. With activity remaining elevated through June and into the summer months, patients and doctors are encouraged to consider flu as well as COVID-19 for any symptomatic individuals.

The bulletin details the recommended composition for the 2022-23 influenza vaccines:

• No changes were made to the A(H1N1)pdm09 or the B/Yamagata egg-based, cell-based, or recombinant vaccine recommended components.
• The recommended A(H3N2) component was changed to an A/Darwin/9/2021 (H3N2)–like virus for egg-based vaccines and an A/Darwin/6/2021 (H3N2)–like virus for cell-based or recombinant vaccines.
• The B/Victoria component recommendation was changed to a B/Austria/1359417/2021–like virus.

With ongoing atypical avian flu circulating in parts of the United States, any influenza in patients with history of contact with birds should also prompt healthcare providers to send samples for testing as happened in Colorado in April 2022, the first human infection with an avian flu strain in the US.