A study published in the Proceedings of the National Academy of Sciences (PNAS) journal showed that SARS-CoV-2 vaccines build longer immunity than antibodies from illnesses, which makes the booster shots essential. A team of scientists from the Yale School of Public Health and the University of North Carolina at Charlotte conducted the study.
Vaccine Immunity vs. Natural Immunity
The study is the first to assess the risk of re-infection and the duration of immunity after exposure to the virus through natural immunity or immunization using a vaccine made by Moderna, Pfizer, Johnson & Johnson, or Oxford-AstraZeneca. The study's analysis considered fluctuations in anti-spike protein IgG antibody levels over time.
According to ANI, the scientists combined long-term immunological data from endemic coronavirus infections, fading antibody levels following zoonotic coronavirus infections, reinfection data from near human-infecting relatives of the virus, and immunological data after SARS-CoV-2 vaccination by using the relatedness of the coronaviruses.
The study showed that, depending on the vaccine type, there is a chance that a person becomes infected despite having a vaccination. The researchers found that Johnson & Johnson and Oxford-AstraZeneca have the shortest length of protection, while Pfizer and Moderna provide longer protection, three times longer than the other two vaccines and natural immunity.
"The mRNA vaccines produce the highest levels of antibody response and in our analysis confer more durable protection than other vaccines or exposures," the study's lead author Jeffrey Townsend said. Yet, he said that natural immunity and vaccination were not mutually exclusive. He added that understanding the relative durability of the vaccines is a key to deciding if a booster is necessary.
According to the researchers, reliable protection against reinfection needs up-to-date boosting with vaccinations that could adapt to changes in the virus that occur as part of the virus' natural development.
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Booster Vaccine Benefit
The striking parallels in reinfection probability between endemic coronaviruses that cause common colds and the virus that causes COVID-19 are the basis for the researchers' data-driven model of infection risks over time. The coronavirus mirrors other viruses that have evolved and reinfected a person even though earlier strains were immune.
Compared to research that just looked at current illnesses, these similarities allowed the scientists to draw predictions for a longer time frame. Additionally, the model enabled comparison by placing antibody responses from both naturally occurring and vaccine-mediated immunity into the same environment.
Alex Dornburg, an assistant professor at the University of North Carolina at Charlotte who co-led the study with Townsend, stated that people tend to forget that we are in an arms race with the virus. He said that the virus would evolve ways to evade a person's natural and any vaccine-derived immune response. He pointed out that vaccines against early viral strains become less effective in battling new viral strains, as is found with the Omicron variation.
Continually updating vaccinations and booster shots is critical in the fight against SARS-CoV-2.
Read also: Lambda COVID Variant Potential Threat and Vaccine Resistance: What Will Scientists Do Now?
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