By Francesco Guarascio

BRUSSELS, (Reuters) – Influenza returned faster than expected to Europe this winter following almost disappearing last season. This raises concerns about a long-term “twindemic”, with COVID-19 and some questions about flu vaccine effectiveness.

The temporary eradication of flu by Europe’s COVID-19 pandemic saw social isolation, mask-wearing, and lockdowns become the norm.

This has been changed by the increased use of vaccines and countries taking less stringent measures to stop COVID-19.

Flu viruses have circulated in Europe since mid-December at a faster rate than expected, according to the European Centre for Disease Prevention and Control (ECDC).

ECDC and World Health Organization data indicate that the December flu epidemic saw a steady increase in cases at European ICUs, with a peak reaching 43 during the final week of 2018.

This is well below the pre-pandemic level. For example, in 2018 flu-related deaths in ICUs topped 400.

However, it’s a significant increase over last December when only one case of flu was reported in ICUs. Data show.

Pasi Penttinen (ECDC’s leading expert on influenza) said that the return of the virus could mark the beginning of an unusually prolonged flu season, which could extend well into the summer.

He stated that if all the measures are lifted, my biggest concern for influenza would be that because there has been so much of the European population suffering from almost zero circulation, we might shift to normal seasonal patterns.

He stated that removing restrictive measures from the spring could increase flu circulation far beyond what is normal for the European season, which ends in May.

The ECDC reported that a “twindemic” could cause excessive stress on already stressed health systems.

According to the data released by France’s health ministry, flu epidemics are currently affecting three French regions, including Paris. Other regions are still in pre-epidemic mode.

France currently has 72 cases of serious flu in France, including six deaths.

DOMINANT STRAIN

The H3 strain of the A virus is currently the most prevalent flu strain. It usually causes the worst cases in the elderly.

Penttinen claimed that the time was not right to give a definitive assessment on flu vaccines. This was because real-world studies required a greater number of patients. However, lab testing has shown that the available vaccines against H3 are not optimal.

The reason is that vaccine makers were unable to accurately predict the dominant strain of flu virus in this season because there were not enough viruses to circulate at the time the vaccines were made.

Vaccines Europe represents the top regional vaccine manufacturers. While they acknowledged that the selection of strains was more challenging due to low flu activity last year, the organization also stated there wasn’t enough data available yet to evaluate the efficacy of the season’s shots.

Flu vaccines are updated every year in order to be as effective against changing flu viruses. Based on the circulation of flu viruses in other hemispheres, their composition is determined six months prior to the start of the flu season. It allows time for drug makers to design and develop the shot.

Europe has not yet collected data about flu vaccination uptake. France has a national flu vaccine coverage rate that is lower than the government had expected.

To boost vaccinations, the authorities extended the vaccine period by one month to February 31. Last week’s figures show that 12 million people had been vaccinated. This is approximately 45% of the target population.

The health ministry stated in a Jan. 11 statement that “there is still much to be done to reduce the effects of the flu epidemic.” This year, the goal is to vacinate 75% people who are at greatest risk.

Vaccines Europe stated that the industry supplied large quantities of flu shots despite the stress on manufacturing facilities from the pandemic.