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Why is the 2nd dose of the Pfizer vaccine so essential

Why is the 2nd dose of the Pfizer vaccine so essential

By Ernie Mundell and Robert Preidt
HealthDay Reporters

WEDNESDAY, July 21, 2021 (HealthDay News) – Pfizer-BioNTech takes two doses of COVID-19 vaccine According to new research, the second dose is increased 100 times by “waking up” cells that play a very important role in the body’s immune response.

Research from Stanford University will help decide why a second dose of mRNA vaccines, such as Pfizer or Moderna shots, is so important immune system the opposite answer SARS-CoV-2.

Bali Pulendran, the author of the study, explained that the current pandemic marks “this is the first time that RNA vaccines have been given to humans, and we don’t know what they do to find out how they do it: offer 95% protection against COVID-19.” Pulendran is a professor of pathology and microbiology and immunology at Stanford.

It has never been clarified how mRNA-based vaccines provide an extremely high level of protection to recipients. new coronavirus. By comparison, the seasonal flu vaccine is considered to be quite effective even if it gets 60% protection.

In the study, the Stanford team looked at blood samples from 56 healthy volunteers at various points before and after receiving the first and second shots of the Pfizer vaccine.

The results showed that the first shot increased the level of specific SARS-CoV-2 antibodies, but not as much as the second shot.

“The second shot has great beneficial effects, surpassing the first shot,” Pulendran said in a university note. “The level of antibodies stimulated a variety of growths, there was only a tremendous T cell response that was present only after the first shot, and the inherent immune response was significantly improved.”

The researchers looked at players in the immune system in addition to the standard antibodies they usually study.

As they did so, interesting new details emerged: the foreground seems to do things that the foreground can’t do, according to a study published in the July 12 issue of the journal. Nature.

The Stanford team was surprised to see that a second dose of the Pfizer vaccine caused a significant mobilization of a small group of first-response immune cells that are usually scarce and dormant.

These cells are a small subset of cells commonly called monocytes, which produce high levels of genes that have antiviral power.

When the COVID-19 virus infects a person these monocytes are hardly activated, there are researchers.

However, the study showed monocytes do respond strongly to the vaccine, but especially after the second dose.

According to the Pulendran group, monocytes had only 0.01% of all circulating blood cells before vaccination, but grew 100 times after the second dose of the Pfizer vaccine, making up 1% of all blood cells.

Also, the cells are less swollen and stronger against viruses, and seem to be able to provide extensive protection against many. viral infections, According to Pulendran.

“It’s amazing the extraordinary increase in the frequency of these cells, just one day after the booster vaccine,” he said. “It is likely that these cells will be able to assemble not only SARS-CoV-2 but also an anti-viral action.

Already, research shows that a strong immune response to SARS-CoV-2 can last at least eight months, and perhaps several years, in people who have received two doses of mRNA vaccines.

Dr. Amesh Adalja is an expert on infectious diseases and an expert at the Johns Hopkins University Health Center in Baltimore. He did not participate in the new study, but reiterated that “it shows that the second dose of the mRNA vaccine regimen significantly increases the overall immunity provided by the first dose.

“This is the reason for the two-dose regimen, and why there are more people who are fully vaccinated than those who are partially vaccinated,” Adalja said. “I suspect the findings would be very similar because they use technology similar to the Modern vaccine.”

More information

The U.S. Centers for Disease Control and Prevention has more mRNA COVID-19 vaccines.

SOURCES: Amesh Adalja, MD, Senior Scholar, Center for Health Security, Johns Hopkins University, Baltimore; Stanford University School of Medicine, release, July 17, 2021

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