Influenza Returns As COVID-19 Spreads, Europe Faces Prolonged Twindemic Threat

JAKARTA - Influenza returned to Europe at a faster-than-expected rate this winter after nearly disappearing last year, raising concerns about a prolonged 'twindemic' with COVID-19 amid some doubts about the effectiveness of the flu vaccine.

The lockdowns, masks and social distancing that have been the rule in Europe during the COVID-19 pandemic paralyzed last winter's flu, temporarily eradicating a virus that globally kills about 650,000 people a year, according to European Union figures.

But that has now changed, as countries adopt less stringent measures to combat COVID-19 due to widespread vaccination.

Since mid-December, the flu virus has been circulating in Europe at higher-than-expected levels, the European Centers for Disease Prevention and Control (ECDC) reported this month.

In December, the number of flu cases in European intensive care units (ICUs) rose steadily to a peak of 43 in the last week of the year, data from the ECDC and the World Health Organization showed.

That's well below pre-pandemic levels, with weekly flu cases in the ICU peaking at more than 400 at the same stage in 2018, for example. But it's a big improvement over last year, when there was only one case of flu in the ICU throughout December, the data showed.

The return of the virus could be the start of an unusually long flu season that could continue into the summer, the ECDC's lead expert on influenza Pasi Penttinen told Reuters.

"If we start lifting all measures, the big concern I have for influenza is, because we've had almost no circulation in the European population for so long, maybe we'll move away from the normal seasonal pattern," he said, as quoted January 17.

He said breaking down containment measures in the spring could prolong flu circulation well beyond the normal end of the European season in May. A 'twindemic' could put undue stress on an already overwhelmed health system, the ECDC said in a report.

In France, three regions, including the Paris region, are facing flu epidemics, according to data published by the French Ministry of Health last week. Others are in the pre-epidemic phase. This season, France has so far recorded 72 serious flu cases, with six deaths.

Complicating matters, the dominant flu strain circulating this year appears to be H3 of the A virus, which usually causes the most severe cases among the elderly.

Penttinen said it was too early to make a final assessment of the flu vaccine as more sick patients were needed for real-world analysis. However, laboratory tests show the vaccine available this year 'would not be optimal' against H3.

That's in large part because there was very little or no virus circulating when vaccine composition was decided last year, making it more difficult for vaccine makers to predict which strains will be dominant in the coming flu season.

Vaccines Europe, which represents the top vaccine makers in the region, acknowledged strain selection was made more difficult by last year's extremely low flu circulation, but added there was not yet enough data to rate the effectiveness of this season's injections.

To note, the flu vaccine is adapted every year to make it as effective as possible against flu viruses that are constantly changing. Their composition was decided six months before flu season began, based on the circulation of the virus in the opposite hemisphere. That gave drugmakers time to develop and make shots.

Data across Europe on the use of the flu vaccine is not yet available. But national figures for France show the coverage is not as wide as authorities had hoped.

Authorities there extended the vaccination period by one month until the end of February to increase inoculations. According to figures released last week, 12 million people have so far been vaccinated, about 45 percent of the targeted population.

"There is still great room for improvement to limit the impact of the flu epidemic," the health ministry said in a statement on Jan. 11. This year's target is to vaccinate 75 percent of people at risk.

Vaccines Europe said the industry had supplied large quantities of flu shots, despite the strain on production facilities brought on by the pandemic.