What is likelihood of getting COVID-19 again in healthy young people?

Young people who have not had COVID-19 have a five times higher risk of contracting coronavirus than those who have had it, The Lancet Respiratory Medicine reported referring to a new study.

In the course of the study, specialists studied the data of about 3,000 recruits of the US Marine Corps - healthy, physically developed people aged 18-20 years.

At the beginning of the study, in May 2020, all participants passed tests for antibodies to the SARS-CoV-2 coronavirus. During this time, none of them had active COVID-19. Then they were monitored until November 2020, PCR tests were carried out to the participants every two weeks.

Of the 189 people who had antibodies to coronavirus (seropositive) at the beginning of the study, about 10% fell ill with COVID-19 during the observation period. Among people who did not have immunity (seronegative), the incidence was about 50%.

According to scientists, the risk of re-infection with coronavirus depends on the level of various types of antibodies in the blood. At the beginning of the study, only 33% of people who were later reinfected had neutralizing antibodies to coronavirus. Seropositive participants who did not get re-infected had 83% of these antibodies.

People who did not have immunity at the beginning of the study, upon infection, produced better antibodies than those who were reinfected again. Compared to those infected for the first time, participants with reinfection had an average viral load of about 10 times lower. However, its values ​​indicated that when reinfected, many of them could infect others.

There were more asymptomatic cases of COVID-19 in the seropositive group - 84%, in the seronegative group - 68%.