Last May, a CDC study revealed that Pfizer and Moderna’s coronavirus vaccines reduce the risk of getting sick from the virus by 94%. (Free Press Photo: JUSTIN TALLIS / AFP)
A scientific study explains that the Pfizer and Moderna vaccines generate an immune reaction that can protect against COVID-19 for years. This would help delay the need for a booster dose.
The researchers indicate that people who received either of the two-dose injections using messenger RNA technology (Pfizer and Moderna) have strong and persistent immune responses. In addition, they produced high levels of neutralizing antibodies against two variants of the virus.
The study was led by Ali Ellebedy, an immunologist at the University of Washington in St. Louis, and was published this June 28 in the journal Nature. In statements to The New York Times the scientist indicated that the research was done only on formulas that use messenger RNA (mRNA) technology, but that they expect the immune response of these to be greater.
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For the research, the experts recruited 14 people who received both doses of the Pfizer vaccine, including eight had previously been infected with covid-19. The experts looked at the lymph nodes, which produce a type of immune system cell known as a memory B cell, during the three, four, five, seven and 15 weeks after the first dose, to analyze the evolution of the immune response.
Memory cells are trained to recognize and fight the virus. These attach to the surface of invading pathogens and mark them for other immune cells to destroy. They can also circulate in the bloodstream for years and the immune system can call them in if there is another infection.
According to the publication of The New York Times, dfter a person is infected with or vaccinated against COVID-19, a germinal center forms in the lymph nodes that acts as a kind of “training ground” for memory B cells. This center helps train cells to recognize the genetic sequence of the virus, as well as any variant in this sequence.
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The scientists found that 15 weeks after the first dose of vaccine, the germinal center was still very active in all 14 participants and the number of memory cells that recognized the virus had not decreased.
This was called a “very, very good sign” by Ellebedy, as germ centers commonly peak a week or two after immunization and then decline. “Usually in four or six weeks there is not much left,” he told the New York Times Deepta Bhattacharya, an immunologist at the University of Arizona, but the germ centers stimulated by mRNA vaccines continue to function months later.
Although the study only looked at people vaccinated with Pfizer, Ellebedy said the findings can be applied to Moderna’s vaccine because they both use the same technology.
Need for reinforcement
The study also suggests that people with weak immune systems, those taking medications that suppress the body’s immunity, or older adults may need boosters.
On the other hand, those who had COVID-19 and were later vaccinated may never need a booster dose. In this way, research suggests that most people vaccinated with mRNA technology will be protected in the long term against existing variants of the coronavirus.
Scientists will continue the observation since it is impossible to predict how long this protection will last, also towards which new variants of the virus its task may continue.