Can vaccinated people spread the virus? CDC tempers comments made by director Rochelle Walensky

"Dr. Walensky spoke broadly during this interview. It’s possible that some people who are fully vaccinated could get COVID-19."

Home base primary care Pharmacist Erin Edmonds fills five syringes with the Johnson & Johnson Covid-19 Janssen Vaccine for use in at home vaccinations at the US Department of Veterans Affairs' VA Boston Healthcare System's Jamaica Plain Medical Center in Boston, Massachusetts on March 4, 2021. - The mobile vaccination team is in it's fifth week of at home vaccinations and has vaccinated 183 veterans so far.  Today marks the first day the Johnson & Johnson single shot Covid-19 Vaccine will be used.  Boston VA received 300 vials of the Johnson & Johnson single shot Covid-19 vaccine so far and expects more on the way.
The CDC tempered comments made by director Dr. Rochelle Walensky that suggested vaccinated people can't get sick or transmit the virus. –Photo by Joseph Prezioso / AFP

The Centers for Disease Control and Prevention on Thursday walked back controversial comments made by its director, Dr. Rochelle Walensky, suggesting that people who are vaccinated against the coronavirus never become infected or transmit the virus to others.

The assertion called into question the precautions that the agency had urged vaccinated people to take just last month, like wearing masks and gathering only under limited circumstances with unvaccinated people.

“Dr. Walensky spoke broadly during this interview,” an agency spokesperson told The Times. “It’s possible that some people who are fully vaccinated could get COVID-19. The evidence isn’t clear whether they can spread the virus to others. We are continuing to evaluate the evidence.”

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The agency was responding in part to criticism from scientists who noted that current research was far from sufficient to claim that vaccinated people cannot spread the virus.

The data suggest that “it’s much harder for vaccinated people to get infected, but don’t think for one second that they cannot get infected,” said Paul Duprex, director of the Center for Vaccine Research at the University of Pittsburgh.

In a television interview with MSNBC’s Rachel Maddow, Walensky referred to data published by the CDC showing that one dose of the Moderna or Pfizer-BioNTech vaccine was 80% effective at preventing infection, and two doses were 90% effective.

That certainly suggested that transmission from vaccinated people might be unlikely, but Walensky’s comments hinted that protection was complete. “Our data from the CDC today suggests that vaccinated people do not carry the virus, don’t get sick,” she said. “And that it’s not just in the clinical trials, it’s also in real-world data.”

Walensky went on to emphasize the importance of continuing to wear masks and maintain precautions, even for vaccinated people. Still, the brief comment was widely interpreted as saying that the vaccines offered complete protection against infection or transmission.

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Misinterpretation could disrupt the agency’s urgent pleas for immunization, some experts said. As of Wednesday, 30% of Americans had received at least one dose of a vaccine and 17% were fully immunized.

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