VU Researchers: Antibodies to Coronavirus Persist for Half a Year

Aurelija Žvirblienė, a professor at the VU Life Sciences Center, says that after an outbreak of coronavirus infection in a Nemenčinė company in April, most of the employees were screened by molecular methods; some of them were more difficult, they were hospitalized and others had no symptoms.

The objective of this study was to evaluate the contradictory information in some studies that the antibodies formed against this virus disappear after 4-5 months, so that those who relapse sometimes become infected again.

They were investigated a second time in June, two months after the outbreak.

“We then discovered that most of the patients had antibodies against the virus, even those who fell ill very easily or had no symptoms,” the researcher said in a VU report.

According to her, another survey was conducted in late October, half a year after the outbreak, and then twice as many people were surveyed as in June, or about 100.

“Everyone who had antibodies in June still had them now. It is a really interesting result that shows that the antibodies do not disappear so quickly. This time a total of 100 people were tested, two-thirds of whom had antibodies. As expected, they had IgG class antibodies indicating a long-lasting infection. However, it is surprising that almost half of them also had IgM class antibodies, which are generally considered an indicator of early acute infection, ”stated A.Žvirblienė.

A representative from the VU Life Sciences Center noted that a third of people who did not have antibodies were simply not infected.

“They weren’t infected. The study included not only those who got sick, but also those who didn’t experience any symptoms, and their molecular test was negative in the spring. The serological test confirmed once again that these people were not really infected and did not get sick, although some worked with infected people, “said the researcher.

Everyone who had antibodies in June still had them now. It is a really interesting result that shows that the antibodies do not disappear so quickly.

According to her, the antibodies found do not mean that these people have not recovered, because even those with severe illness no longer have the virus.

Recurrence does not guarantee absolute immunity

However, A.Žvirblienė emphasized that even the World Health Organization is of the opinion that there is not enough scientific data to confirm that a positive result of a serological test indicates acquired resistance.

“Several cases have been described in which people who have become ill have become re-infected. However, these are quite rare cases, although millions of people around the world have already been infected, it is likely that their risk of contracting the virus is lower than that of those who have not been, “he said.

The scientist explains reinfection by other processes in the body.

“Immunity is not just about antibodies. An important cellular response is T lymphocytes, whose activity is difficult to measure. It is even more difficult to measure whether immune memory cells form because they are inactive and only start working when exposed to the viruses repeatedly. Therefore, resilience is determined by many factors “, emphasized A.Žvirblienė.

“However, I think that the formation of antibodies and their survival for so long, half a year, is a sufficiently important indicator of immunity.” It gives hope that our immune system is not so powerless against this virus, “he said.