HomeHealthPeople who have overcome COVID-19 would have a low risk of reinfection
People who have overcome COVID-19 would have a low risk of reinfection
March 2, 2021
People who have overcome COVID-19 appear to have a lower risk of reinfection by the virus, "at least for a few months", although more studies are needed to determine how long it lasts and how the characteristics of the patient affect that protection.
A study published in the journal Jama by the US National Cancer Institute (NCI) focused on better understanding whether detectable antibodies to SARS-CoV-2 protect people from reinfection with the virus and what extent. For this, the researchers analyzed the antibody test results of more than 3 million people who underwent that test in the United States.
Approximately 11% of the individuals with SARS-Cov-2 antibodies (seropositive) and 9.5% of those without subsequently underwent PCR testing, and the team reviewed the results at various time intervals, as some Recovered people can shed viral material for up to three months, although they are unlikely to remain infectious throughout that period.
Tests of ninety days or more – when any coronavirus detected by PCR is likely to reflect a new infection – indicated that only about 0.3% of those who were seropositive tested positive, about one-tenth the rate of seronegative.
The data "suggest that people who have a positive result on a commercial antibody test appear to have substantial immunity to SARS-CoV-2, which means they may have a lower risk of infection in the future"according to Lynne Penberthy, NCI and study director.
However, he considered, "more research is needed to understand how long this protection lasts, who may have limited protection, and how it may affect patient characteristics, such as conditions comorbid. However, we are encouraged by this first finding.".
The authors note limitations in the study, in particular that the results come from a scientific interpretation of real-world data, which are subject to biases that could be better controlled in a clinical trial.
Other studies published in countries such as Finland or the United Kingdom concluded, for example, that people who were infected with the coronavirus generated antibodies for six months.