Owith highly transmissible versions of Omicron now causing almost all of COVID-19 infections in the United States, most people have probably been infected, even if they have been vaccinated and strengthened. So people naturally wonder if they really need to get the last booster shot, which is the first to target the Omicron variant. Most people correctly assume that after recovery they have developed a fairly good immunity to the virus.
While this is true, researchers are learning more about the different types of immunity provided by natural infection with the virus, compared to that provided by vaccines and boosters. Studies show that after natural infection with a particular strain of SARS-CoV-2, people tend to develop significant levels of anti-virus antibodies against that version of the virus. This response may even, in some cases, be broad enough to provide protection against a wider range of different strains of the virus. If you are infected, the immune system reacts to all the different proteins made by the virus. When you are vaccinated, on the other hand, the body responds only to the viral targets targeted by the vaccines, which are a more limited set of viral genes. This is why the original vaccine, which contained genetic information from the widely released first strain of SARS-CoV-2, no longer appears to protect people against infection by the latest variants of the virus, in particular Omicron BA.4/ 5.
But there is a caveat to this potential benefit of natural infection. The immune response the body generates also correlates to the amount of virus the body sees. So if someone is exposed and infected with a large dose of the virus, the body will produce a stronger and more widespread response than if someone is infected with a smaller amount of SARS-CoV-2. This means that not all natural infections are created equal, and there’s usually no way for people to know how much exposure they’ve had once they’ve been infected. This information comes from laboratory PCR tests, which measure viral load, and most people no longer go to doctor’s offices, clinics or hospitals for COVID-19 tests, but self-test at home. with rapid antigen tests, which are not designed to provide information on viral load.
A 2021 study even found that not all infected people necessarily develop anti-virus antibodies; in this trial, conducted with volunteers recruited from the University of Alabama at Birmingham, about a third of people did not develop detectable levels of antibodies even after testing positive in PCR tests for COVID-19. The researchers found that the more severe the symptoms, the more likely they were to produce antibodies, and many people infected with the recent Omicron variants had mild or no symptoms, meaning that those asymptomatic people had no – not be generated appreciable symptoms. antibody level.
There is also the question of the duration of protection against natural infections. Whether you were naturally infected or vaccinated, studies show that antibody levels, which are the first line of defense to protect against infection, decline after several months. It’s also possible that vaccines produce a deeper type of immunity that involves not just antibodies, but another type of immune cell called T cells that can remember and mount aggressive responses to a virus it recognizes if the people are infected again. A 2021 study found that people who had COVID-19 and were not vaccinated had a twice as high risk of being re-infected as people who got vaccinated after having COVID-19.
The bottom line is that any immunity, whether from natural infection or vaccines, does not last forever. And because COVID-19 is a relatively new disease, researchers are still trying to unravel how the body reacts to the virus and what kinds of immunity the immune system generates. As these data grow, the most reasonable strategy at this point is to continue to build immunity in order to achieve the best possible protection against SARS-CoV-2 infection or severe disease. . That means get booster doses even if you have been infected, approximately three months after your recovery.
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