RESEARCHERS of an unpublished study have claimed that one-fifth of people who have had Covid-19 do not have a specific type of antibodies and therefore may not have adequate protection against future infections.
The study tested volunteers with a previous SARS-CoV-2 infection for the presence of a type of antibody that only a natural infection can generate called core anti-N antibodies.
Smokers and individuals with existing medical conditions were particularly likely to test negative for the antibodies.
Critics of the study say the presence of this type of antibody is a poor indicator of overall immunity to future COVID-19 infection.
They also point out that surveys relying on the core anti-N antibody may underestimate levels of infection with COVID-19 in the community.
People who have had COVID-19 sometimes argue that they do not need to be vaccinated because their infection has given them immunity against the virus.
But a new study suggests that around a fifth of individuals who recover from COVID-19 may not have adequate protection against future infections.
“Our data shows that the best way to protect yourself and others from COVID-19, even if you have had the virus previously, is to have two doses of vaccine and the booster when offered,” says the study’s lead scientist Dr. Tim Spector, professor of genetic epidemiology at King’s College London in the United Kingdom.
The study found that 19% of people with a previously confirmed infection did not produce anti-N antibodiesTrusted Source.
These antibodies target a protein, called the nucleocapsid, found inside SARS-CoV-2, the virus that causes COVID-19.
Only a natural SARS-CoV-2 infection can generate anti-N antibodies, whereas vaccines provoke the production of antibodies against its spike protein, which resides on the outside of the virus.
The study reported on 8,193 adults who reported a previous SARS-CoV-2 infection — confirmed with a PCR test — using the ZOE COVID smartphone app.
Each participant also reported at least one symptom in the subsequent 2 weeks and responded to an invitation to undergo home anti-N antibody testing.
The researchers did not provide information on the response rate to their request for additional testing. The scientists behind the app sent out invites between April 2021 and August 2021.
