Blood samples obtained from people a month after they'd gotten their booster shots showed a level of antibodies against Omicron that were equal to those seen against other variants after two doses.
/webmd/consumer_assets/site_images/article_thumbnails/video/1800x1200_krames_activating_health_how_mrna_vaccine_works_video.jpg“That Pfizer lab report came back saying that the expectation is that the existing vaccines protect against Omicron. But if you get the booster, you're really in good shape. And so that's very encouraging,” he said in an afternoon press briefing.
The types of lab tests that were run were different, too, and involved small numbers of blood samples from patients.depends not just on neutralizing antibodies, which act as a first line of defense when a virus invades, but also on B-cells and T-cells, and so far, tests show that these crucial components which are important for preventing severe disease and death, had been less impacted than antibodies.
Ciesek and her team exposed Omicron viruses to the antibodies of volunteers who had been vaccinated the boosted with the Pfizer vaccine three months prior. She also compared the results to what happened to those same 3-month antibody levels againstviruses. She found only a 25% neutralization of Omicron compared to a 95% neutralization with Delta. That represented about a 37-fold reduction in the ability of the antibodies to neutralize Omicron vs. Delta.
“What the booster really does in neutralizing Omicron right now, they don't know, they have no idea,” says Peter Palese, PhD, chair of the department of Microbiology at the Mount Sinai School of Medicine in New York.“There are four major sites on the spike protein targeted by antibodies from the vaccines, and all four sites have mutations,” he says. “All these important antigenic sites are changed.