Immunity levels high: scientists
Ten times more people than previously thought may have already acquired immunity to the coronavirus, according to a groundbreaking study in Germany.
Scientists from the University of Bonn yesterday claimed their findings show that 1.8 million people across Germany have already been infected with the virus.
That is more than 10 times as many as have tested positive so far, and would mean more than 1.6 million may have been infected and recovered without knowing it.
The findings are based on the first comprehensive study of the effects of the virus on a single community in Gangelt, the town at the epicentre of Germany’s first major outbreak. The study’s initial findings last month suggested the fatality rate in Gangelt was much lower than previously thought, at just 0.37 per cent.
The study’s authors now believe this is the general fatality rate for the virus and that it can be used to extrapolate the total number of undetected infections from the death toll.
‘‘Because our research allows us to determine exactly how many individuals are infected, we can also determine the per centage of deaths among all those infected with great accuracy,’’ Professor Hendrik Streeck, the study’s leader, said as he announced the study’s final findings yesterday.
‘‘The infection fatality rate is a property of the virus. It can, to a degree, be applied to all of Germany – corrected for demography, of course.’’
It is still not clear whether those who recover from the virus have any form of immunity, or how long it may last, Streeck told Frankfurter Allgemeine Zeitung newspaper. ‘‘But we can draw conclusions from the laboratory,’’ he said. ‘‘Trained immune responses can block the virus, and we know in the case of other corona viruses that you can have at least partial immunity.’’
So far, 165,745 have tested positive for the virus in Germany and 6866 people have died, according to Johns Hopkins University. That suggests a fatality rate of 4.1 per cent, but most scientists believe there are many more undetected infections. The majority of those who are infected show only mild symptoms, and a fifth show no symptoms at all, the Gangelt study found.
‘‘The fact every fifth infection apparently has no noticeable symptoms suggests it is not possible to identify infectious people this way,’’ said Professor Martin Exner, another of the study’s authors.
‘‘Every apparently healthy person we encounter could be unwittingly carrying the virus. We have to keep this in mind and act accordingly.’’
The Gangelt study has proved controversial in Germany. Rival scientists have questioned its methodology and they were quick to cast doubt on yesterday’s findings. Professor Gerard Krause of the Helmholtz Centre for Infection Research pointed to the fact only seven people are known to have died of the virus in Gangelt.
‘‘That means one death more or less would make a really significant difference to the study,’’ he said.
The findings come as Germany faces a ‘‘week of truth’’, with the first reliable data on lifting its lockdown expected within days.