Flu Season 2022 Begins Traveling to the Southern Hemisphere

Co-circulation of influenza and SARS-CoV-2 viruses may confront south America
airplanes crossing in the sky
(Vax Before Travel)

While the Northern Hemisphere was fortunate to bypass most of the 2021-2022 flu season, the Southern Hemisphere may not be as lucky.

People traveling between the Northern and Southern Hemispheres can be exposed to virus variants where they are currently circulating.

According to the World Health Organization (WHO) Global Influenza Update N° 413 published on February 22, 2022, ‘with the increasing detections of influenza during the COVID-19 pandemic, countries are recommended to prepare for co-circulation of influenza and SARS-CoV-2 viruses.’

In temperate regions, influenza typically circulates at higher levels during colder winter months: October to May in the Northern Hemisphere and April to September in the Southern Hemisphere.

Influenza viruses spread from person to person, primarily through respiratory droplet transmission, such as when an infected person coughs or sneezes. And when a passenger sneezes on an airplane, viruses can quickly spread throughout the cabin.

The WHO confirmed that in the southern hemisphere's temperate zones, influenza activity has remained low overall in 2022. However, increased detections of influenza A(H3N2) were recently reported in some countries in temperate South America.

The WHO says ‘clinicians should consider influenza in differential diagnosis, especially for high-risk groups for influenza, and test and treat according to national guidance.’

They are also encouraged to ‘enhance integrated surveillance to monitor influenza and SARS-CoV-2 simultaneously, and step-up their influenza vaccination campaign to prevent severe disease and hospitalizations associated with influenza.’

Separately, the U.S. CDC says in the temperate regions of the Southern Hemisphere, influenza activity typically occurs during April – September each year.

The CDC suggests that international travelers ensure they are up to date with flu shots when flying to the Southern Hemisphere in 2022.

In the U.S., annual vaccination for seasonal flu protection is recommended for those aged ≥6 months and is the most effective way to prevent influenza and its complications. Several influenza vaccines are approved for use in the U.S., which are listed on this webpage.

Furthermore, the CDC recently published updated vaccination schedules for 2022, including flu shot co-administration information.

Vax-Before-Travel publishes fact-checked research-based travel vaccination news.

Our Trust Standards: Medical Advisory Committee