The winter flu season has begun. By late December, the annual influenza wave had started in the east of the WHO European Region, with an increase in cases detected in the Russian Federation, Kazakhstan and Azerbaijan. Now flu is ‘widespread’ in Poland, Sweden and Norway, with ‘sporadic’ reports in Germany, the Netherlands and the United Kingdom.
Some governments are growing concerned that uptake of the flu vaccine is low. In France, for example, the annual flu vaccine campaign has been extended to the 28th of February to give more time to increase vaccination rates. Some US experts have expressed concern that flu vaccination is being overlooked while attend focuses on the omicron variant of SARS-CoV-2.
For most countries, the 2020/2021 flu season never came. Measures introduced to contain the spread of COVID-19, including mask wearing, hand-washing and social distancing, helped to prevent large numbers of influenza cases. In addition, flu vaccine uptake was higher than in previous years as citizens and health authorities feared the impact of a ‘twindemic’ (simultaneous epidemics of COVID-19 and flu).
Now, with countries across Europe recording record-breaking levels of COVID-19, a February surge in flu cases may be on the horizon. Whether the omicron wave is in decline by then remains to be seen. Some countries, including Israel and the US, are already reporting rising rates of hospitalisation with flu. There are also reports of patients being co-infected with both viruses at the same time, prompting social media users to coin the hashtag #flurona.
The European Centre for Disease Prevention & Control (ECDC) estimates that in a typical year, 5% to15% of the population is affected by influenza, leading to between 3 million and 5 million cases globally. ‘With COVID-19 also in high transmission across our Region, there is a risk that this so-called twindemic could put excessive pressure on already overstretched health systems,’ the agency said.
Most cases seen to date have been influenza A(H3N2) viruses. This is causing mostly mild illness, but in older adults is known to come with a higher risk of severe disease and death. Fewer H1N1 or influenza B cases have been detected, but this can change through the course of the winter.
The ECDC says it is too early to estimate the effectiveness of the current flu vaccines in protecting against severe illness. National authorities are encouraged to monitor the situation closely to help experts understand the potential timing and severity of this influenza season, and to continue to encourage vaccination.
Older people, pregnant women, young children, immunocompromised people and those with chronic underlying medical conditions should be prioritised, the agency said. In addition, health workers are urged to vaccinate to protect themselves, limit the spread of the virus and protect health systems already facing serious staff shortages.
It appears 2022 will have a flu season. Whether it delivers an unwelcome ‘twindemic’ which causes high levels of illness and puts severe pressure on health systems will soon become clear.