The consequences of the pandemic are far-reaching – one could be that other viruses, which humanity thought to be masters for a long time, are circulating more strongly again. For the polio and measles viruses, various organizations are now warning of just such a flare-up of infections.

Pia Heinemann

Editor Nature and Science

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In a report last week, the United Nations Children's Fund (UNICEF) drew attention to the fact that around 67 million children had failed to receive routine vaccinations in whole or in part between 2019 and 2021. The causes were the lockdowns and obstructions in health care during the pandemic. The report also notes a decline in confidence in childhood vaccinations.

"More than a decade of hard-won advances in routine childhood immunizations have been undermined," the report said. Getting back on track with the vaccinations of the children will be a "difficult" task.

According to the report, vaccination coverage of children fell in 112 countries and fell globally by five percentage points to 81 percent – the lowest level since 2008. Africa and South Asia are particularly hard hit by this vaccination deficiency among children.

The proportion of children vaccinated against measles worldwide also fell from 2019 to 2021 percent between 86 and 81, according to the report. "Vaccinations have played a really important role in helping more children live healthy and long lives," said the report's chief editor, Brian Keeley. "Any decline in vaccination coverage is worrying."

According to the report, confidence in child vaccinations declined in a large majority of the countries surveyed: In 52 out of 55 countries, awareness of the importance of vaccination declined. In most countries, people under the age of 35 and women in particular said that their confidence in routine childhood vaccinations had tended to decline since the pandemic began.

The European Disease Control Agency (ECDC) also comments on the relapse in childhood vaccinations, but extends the time arc. Between 2012 and 2021, about 2.4 million children in Europe were not vaccinated with polio, the agency said. Unvaccinated subpopulations can become a real problem.

Regression in eradication

Europe had been declared polio-free in 2022, and the regular vaccination campaign meant that the virus, which causes polio, could hardly infect people. In other regions of the world, however, it still circulates both in the wild form and in the form of vaccine viruses. The disease always occurs sporadically or even in smaller outbreaks. If viruses are imported into Europe from such countries and accidentally enter an unvaccinated population, infections and diseases can occur here as well. ECDC Director Andrea Ammon said: "As long as there are still unvaccinated or insufficiently vaccinated groups, the risk of reintroduction in Europe remains." This also applies to measles, a virus that is also extremely contagious. There can be outbreaks that put a strain on the health care system," Ammon says, "even in countries where measles has already been eliminated." The ECDC emphasizes that the 99 percent decrease in measles cases reported in 2022 has been achieved less by good vaccination coverage than by Covid prevention measures.

The health organizations WHO, Unicef and the Bill & Melinda Gates-supported vaccine alliance Gavi and other international and national immunization organizations have launched the initiative "The Big Catch-up" this week because of the regression in immunization. The aim is to quickly close the vaccination gaps among children that have arisen as a result of the pandemic. Diseases such as measles, polio, yellow fever and diphtheria are the focus of the campaign.

The initiative says it focuses on the twenty countries that are home to two-thirds of children who have not been vaccinated during the Covid pandemic.