Kathimerini Greece Newsroom
Coronavirus antibodies show up even 20 months after the disease in almost all organisms that survive Covid-19, according to a new US study. But it is not clear whether they protect against new infections, especially with newer mutations.
Research by leading medical school researchers at Johns Hopkins University in Baltimore has shown that 99% of unvaccinated coronavirus patients have had antibodies to the virus' protein for more than a year and a half after they were found to have contracted the coronavirus.
The study, led by Dr. Jennifer Alejo, was based on antibody testing in three different groups of volunteers, all of whom were unvaccinated. The first group had 295 participants who tested positive for Covid-19, the second 275 people who thought they had a coronavirus without ever having been tested, and the third 246 volunteers who thought they had never had the coronavirus.
The antibody test showed that in the period from 0 to 20 months after the positive coronavirus diagnosis, 99% of the first group had antibodies against the coronavirus pin that binds to the cell, with a high average of 205 per milliliter. There does not appear to be a relationship between when they were diagnosed and the level of antibodies.
In the second group, antibodies were found only in 55% of individuals, with an average of 131 U/mL, while in the third only in 11%, with an average of 82 U/mL.
The researchers' report, published in the Journal of the American Medical Association, said: "Although the evidence for the natural immunity of unvaccinated healthy American adults up to 20 months after confirmed Covid-19 infection remains encouraging, it remains unclear to what extent these antibody levels are associated with protection against future SARS-CoV-2 infection, particularly with the new strains being recorded.
After all, as a rule, those who were infected more than 20 months ago had the original strain of the coronavirus, that of Wuhan.