How strong is immunity after a coronavirus infection?
Last reviewed: 12.03.2022
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Experts said that unvaccinated people who have recovered from COVID-19 can get sick again after 3 months. Immunity after a disease of any degree of complexity is not stable.
Employees of the Yale College of Public Health and the University of Charlotte of North Carolina spoke about this feature of the coronavirus infection. But with vaccinated people, the situation is different: their immune defense is more stable and long-term.
Experts analyzed information about patients who were re-infected with COVID-19 viruses . As a result, they identified the most likely risks. It was found that the pathogens of coronavirus infection are able to adapt and not die even in potentially dangerous conditions for them. In addition, the infectious agent can again freely enter the body - for example, if a person has weakened immune defenses, or immunity has not fully recovered after the first disease.
Scientists performed a phylogenetic assessment of individual genes and reconstructed molecular phylogeny with the most recreated probability of human infection with a coronavirus infection. Such phylogeny helped to compare the levels and quality of antibodies, to check data on re-infection with endemic coronaviruses. Next, the researchers analyzed various human conditions to assess the expected decrease in antibody levels over different periods of time, to determine the likelihood of re-infection. As a result, the following information was obtained: re-infection with coronavirus in an endemic environment can occur within a period of 3 months. Up to 5 years after the ultimate surge of antibodies. The median is 16 months.
The period when a person can be re-infected is a very important indicator for all public health. As the pandemic spread of coronavirus infection continues, re-infections are likely to be observed everywhere. Scientists strongly recommend that in order to contain the transmission of the pathogen, including among recovered people, it is necessary to direct all efforts to accelerate vaccination. This is the only way to prevent morbidity and mortality from COVID-19. In general, according to experts, the risk of re-infection largely depends on the state of the human immune system, on the mass penetration of the pathogen into the body, on cross-immunity, age category, etc. Unfortunately, during the study, scientists were unable to cover all these factors and their interactions. However, the work will continue, and soon medicine will be able to make predictions and model epidemiology, prevent possible consequences and prevent re-infections.
A complete picture of the study is presented on the page of The Lancet