Mild Forms of Covid-19: Immunity Reduces after Infection
Mild forms of Covid-19 decreases immunity after infection. Bad news for patients who have had a mild form of Covid-19 is that the amount of antibodies in the blood lowers two months after the onset of symptoms. Previous studies spoke of longer immunity.
Antibody presence decreases after two months after developing a mild form of Covid-19, which implies that these patients continue to respect barrier gestures.
When a person is contaminated with a virus, our immune system creates antibodies to defend itself. This allows it to fight off the infectious agent now, but also in the future. In the case of Covid-19, little data is available on the duration of immunity to the disease.
A research group consisting of researchers from Inserm, the Institut Pasteur, the Sorbonne and the Pitié-Salpêtrière hospital interested in the subject. In the journal Nature Communications, researchers present their results: two months after infection, the level of antibodies decreases, in the case of a mild form of the disease.
How does the antibody level change?
The research team investigated the medical data of 26 healthcare workers who contracted a mild form of Covid-19. “The results of the following study show that all of these professionals developed antibodies between two & four weeks after the onset of symptoms as well as a neutralizing response to SARS-CoV-2,” said a statement.
This immune reaction is associated with the IgG and IgA type antibodies, whose action is concentrated on the S protein of the virus. This prevents it from attaching itself to cells to infect them. Scientists find that IgA antibodies are essential for the early immune response against the virus, and two months after the first symptoms, their quantity in the body decreases rapidly.
According to this study, they even disappeared entirely after two months for 15% of health professionals. “This work is in favour of maintaining protective measures and barrier gestures and of the benefit of vaccination of healthcare professionals who have had COVID-19”, the researchers conclude.
Mild Forms of Covid-19: Several contradictory studies
This study contrasts with previous research, the results of which were presented in January. Carried out in 188 patients, 90% of whom had had few symptoms, it indicated that immunity persisted for up to eight months after infection.
Further research will be needed to better understand the evolution of the immune response to Covid-19, depending on the severity of the disease. Pending receipt of these data, having contracted Covid-19 does not guarantee total protection against a new infection, hence the importance of the vaccination campaign and continuing to apply barrier measures.