‘Twindemic’ risks warrant immediate steps in Europe and the US

Recent reports show that influenza cases are rising in the US and the UK. The intensity of the flu season in North America and Europe can be predicted by Australia’s flu season, having occurred months before the northern hemisphere’s winter period. This year, Australia experienced its worst flu season in five years. At its height, more than 30,000 cases were reported each week, according to the Australian Government Department of Health and Aged Care. To date, 83.1% of cases have been due to influenza A (H3N2), which causes more severe epidemics, according to a 2022 publication in JAMA Network Open by Hansen and colleagues. 

It is postulated that the sharp increase in cases was driven by two factors: increased public contact due to the relaxing of Covid-19 measures and reduced herd immunity against influenza. In addition, seasonal influenza vaccine uptake decreased during the Covid-19 pandemic. These factors are also true in Europe and the US. 

This suggests a very difficult winter period ahead for health services. General uptake of Covid-19 boosters has also been poorer than expected, even with the launch of the new Omicron-specific bivalent boosters from Moderna and Pfizer/BioNTech. Unless immediate action is taken, health services will be overwhelmed, as Australia’s has been. Governmental bodies should use Australia as a case study and make decisions now to prevent this. Strategies include public health messaging to promote the influenza vaccine and Covid-19 booster uptake in vulnerable populations, subsidising flu vaccines to non-vulnerable individuals, and running campaigns to help improve public awareness of both viruses along with steps to reduce infection.