Patients With Asymptomatic COVID-19 Develop Poorer Immunity Against Virus

Patients with asymptomatic COVID-19 develop poorer immunity against virus

Scientists have found fewer antibodies against coronavirus and anti-inflammatory cytokines in their blood.

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Scientists conducted a detailed analysis of the immune response to the SARS-CoV-2 coronavirus in 37 people who suffered from COVID-19 in an asymptomatic form. It turned out that in this category of patients, the immunity that remains after infection is weaker than in those who have had a disease with a detailed clinical picture. This showed a new study published in Nature Medicine.

According to modern data, most COVID-19 proceeds with symptoms of varying severity, which appear after an incubation period of 2-14 days. But in a minority of those infected, positive tests for coronavirus are not accompanied by a detailed clinical picture. A number of questions are associated with the asymptomatic course of the disease among doctors. One of them is whether it develops full-fledged immunity to the virus.

Scientists examined 178 patients between the ages of 8 and 75 who had suffered from COVID-19 in China before April 10, 2020. The average duration of illness in the presence of symptoms was 19 days, while in the case of asymptomatic disease it was 14.

During the acute phase of the disease - when the virus could be detected in a nasopharyngeal swab - in the absence of symptoms, the level of immunoglobulins G (IgG) was significantly lower. IgG - antibodies that the body is able to produce after an illness or vaccination to protect against a particular infection.

Eight weeks after discharge, antibody levels decreased in 81.1% of asymptomatic patients and in 62.2 patients who had symptoms during the acute phase of the disease. In the first group of people, the decrease in the level of antibodies was more pronounced.

Also, asymptomatic patients had lower levels of anti-inflammatory cytokines in their blood, indicating a weaker immune response to COVID-19, the scientists point out.

The authors of the study believe that new data are calling into question the effectiveness of the introduction of "immune passports". In their opinion, in order to prevent the disease, it is necessary to continue mass testing and, as necessary, quarantine. How long antibodies can persist after suffering COVID-19 and to what extent they protect against disease should be shown in future, larger studies.