Influenza has returned to Europe at a faster-than-expected rate this winter after almost disappearing last year, raising concerns about a prolonged "twindemic" with COVID-19 amid some doubts about the effectiveness of flu vaccines.
The return of the virus could be the start of an unusually long flu season that could stretch well into the summer, the ECDC's top expert on influenza Pasi Penttinen told Reuters.
"If we start to lift all measures, the big concern I have for influenza is that, because we have had such a long time of almost no circulation in the European population, maybe we will shift away from normal seasonal patterns," he said.
He said dismantling restrictive measures in the spring could prolong the circulation of flu far beyond the normal end of the European season in May.
A "twindemic" could put excessive pressure on already overstretched health systems, the ECDC said in its report.
Penttinen said it was too early to make a final assessment of flu vaccines because a larger number of ill patients was needed for real-world analyses. But lab tests show the vaccines available this year "are not going to be optimal" against H3.
That is largely because there was very little or no virus circulating when the vaccines' composition was decided last year, making it harder for vaccine makers to predict which strain would be dominant in the coming flu season.
