Herd immunity will likely be impossible to achieve without vaccinating children and adolescents, according to the German Society for Immunology (DGfI).
"Typically it is assumed there will be a herd immunity when 60 to 70 per cent of the population is protected against the pathogen. But that presupposes that the pathogen cannot multiply in those individuals," DGfI Vice President Reinhold Foerster told the Funke Media Group newspapers in comments published on Tuesday.
Foerster says it is a different matter with Sars-Cov-2: people can transmit the virus even though they are not ill themselves, even though they are vaccinated and symptom-free.
The Delta variant has intensified the situation, he said.
"It is much more contagious. It very much affects adolescents and children," he said.
"As long as this group is not vaccinated at all or only vaccinated a bit, we will not get any herd immunity."
According to Germany's Robert Koch Institute (RKI) for disease control (RKI), at least 85 per cent of the population aged 12 to 59 and 90 per cent of those 60 and older should be fully vaccinated to tackle the Delta variant.
"If this vaccination rate is achieved in time, a pronounced fourth wave in the coming autumn/winter seems unlikely," according to an RKI paper released Monday.
For now, the country's Standing Commission on Vaccination (Stiko) has not issued a general recommendation for children aged 12 and over to be vaccinated, and there is no approved vaccine for children under 12.
