Health experts say that one dose of the Pfizer or Moderna COVID-19 vaccine is effective against the coronavirus, according to
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New research from the Centers for Disease Control and Prevention has determined that Pfizer and Moderna’s mRNA vaccines for COVID-19 are “exceedingly effective at preventing the disease after just one dose.”
A recent study analyzed data from at least 3,950 health professionals and essential and frontline workers who underwent weekly testing for the coronavirus for a duration of 13 weeks after they were vaccinated.
“[R]esearchers discovered that the vaccines were 80 percent effective at preventing COVID-19 after one dose, and 90 percent effective after two doses,” the outlet noted.
In clinical trials, the Pfizer-BioNTech vaccine was 52% effective after just one dose, and 95% effective after two doses.
For Moderna’s clinical trials, the vaccine was 50.8% effective up to two weeks after the original dose and 92.1% effective after that, with an efficacy of 94.1% after two doses.
Dr. William Schaffner, infectious diseases specialist and professor at the Vanderbilt University School of Medicine, said that he’s “not entirely sure” why there has been such a large increase in how effective the COVID-19 vaccines are in preventing disease after just one dose.
“[T]his is data from continuing analysis of larger populations,” he told the outlet, “and it’s encouraging.”
The encouraging data, according to Dr. Shobha Swaminathan — an association professor in the Division of Infectious Diseases at Rutgers University — “supports what many of us have felt.”
“After two weeks, most vaccines will have some efficacy, and the degree of efficacy would relate to the potency of the vaccine,” Swaminathan said.
Swaminathan added, “We do not know how durable the vaccine response will be for these products if people stop at one dose.”
But experts say that it remains of utmost importance for people to receive two shots of a two-shot COVID-19 vaccine series.
“I do think we need that second dose in order to get maximum protection,” Schaffner added, insisting that people get “much more antibodies” when they receive the second dose. “Please get the second dose. You need to get complete protection. We can’t tell you that you’re going to have 95 percent protection on the basis of a single dose, and you’re likely to have longer protection this way.”
Dr. Thomas Russo, professor and chief of infectious diseases at the University of Buffalo in New York, added, “I can’t emphasize enough how important it is to get the second dose. … Only a minority of people have severe, systemic symptoms. Even if you have flu-like symptoms, you take a ‘vaccine day.’ It’s a small price to pay for getting a really tremendous degree of protection from this coronavirus.”