The claim: CDC director says vaccines can’t prevent transmission of COVID-19
As the omicron variant surges across the world and the United States logs case numbers near and over 1 million per day, the virus is prompting scientists to develop new treatments and government officials to fight to curb the spread.
While the Biden administration continues to urge Americans to get vaccinated, a Jan. 10 Facebook post claims that Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said vaccines can’t prevent COVID-19 transmission. Other sites have shared the same claim, linking Walensky’s words back to an interview with CNN in August 2021.
“Our vaccines are working exceptionally well,” Walensky said to CNN’s Wolf Blitzer in the interview. “They continue to work well for delta, with regard to severe illness and death – they prevent it. But what they can’t do anymore is prevent transmission.”
Special access for subscribers! Click here to sign up for our fact-check text chat
Though Walensky did say these words on CNN, the original interview was aired in early August, not recently. And while it’s true vaccines can’t entirely halt transmission, experts say they do reduce it – and reduce the chances of hospitalization and death – as USA TODAY previously reported.
USA TODAY reached out to the original poster of the claim for comment.
Vaccine effects depend on several factors
In an email, Walensky spokesperson Kathleen Conley wrote that in August 2021 – when the interview originally ran – the delta variant was the dominant variant in the United States.
Experts at that time said it was clear the vaccines provided protection.
“Vaccines provide significant protection from ‘getting it’ – infection – and ‘spreading it’ – transmission – even against the delta variant,” Akiko Iwasaki, a professor of immunobiology and molecular, cellular and developmental biology at Yale University, told USA TODAY in November.
However, Conley noted data did show vaccines were “less effective at preventing infections and transmission with Delta than with previous other variants.” Omicron has proven even more difficult to contain.
While mRNA vaccines – produced by Pfizer and Moderna – continue to offer some level of protection against transmission of omicron, other vaccines – such as Johnson & Johnson, Sinopharm and AstraZeneca – offer “almost no defense,” according to a Dec. 19, 2021, report by the New York Times.
Other factors beyond variant type, vaccination type and booster status can also influence whether or not a person contracts COVID-19.
Dr. David Dowdy, associate professor of epidemiology at Johns Hopkins Bloomberg School of Public Health, said it’s difficult to succinctly explain the vaccines’ nuanced effects on transmission.
A vaccine might protect you from a passing interaction with someone at a grocery store, but it may not prevent infection from someone you live with and share air with for several hours a day.
“It gets very easy to misconstrue,” Dowdy said. “If someone asks, do vaccines prevent infection, and you have to give a yes or no answer, then the answer is no, they’re not a perfect blockade. But do the vaccines offer some protection against infection? The answer is yes.”
Vaccines still protect against serious disease
While vaccinations don’t offer perfect protection against the transmission of COVID-19, experts still urge people to get vaccinated.
According to Conley, COVID-19 vaccination remains effective against hospitalization and death caused by the virus. Getting a booster, she added, further decreases these risks, and the CDC continues to recommend that Americans receive vaccines and boosters.
Dr. Chris Beyrer, professor of public health and human rights at the Johns Hopkins Bloomberg School of Public Health, said both the mRNA and J&J vaccines were never designed to prevent infection entirely.
It’s “very hard”, he said, to prevent infection via an injected vaccine when you’re dealing with a virus that enters the body through the nose and mouth. Instead, the vaccine trials were designed to study reduction in serious illness, hospitalization and death. All three vaccines were highly effective by this measure, Beyrer said.
“People who say, well, why would I take it if it doesn’t prevent me from getting infected?” Beyrer said. “You have to remember that having a COVID-19 infection can be everything from completely asymptomatic … to a head-cold-like symptoms or full flu-like symptoms, all the way to death. So what the vaccines are doing is really dramatically increasing the likelihood that you will have mild infection. And that’s incredibly important.”
A CDC study released Jan. 21 showed booster shots of the Pfizer-BioNTech and Moderna vaccines were 90% effective at preventing hospitalizations from the omicron variant.
Our rating: Missing context
Because it can be misleading without additional information, we rate MISSING CONTEXT the claim that the CDC director says vaccines can’t prevent transmission of COVID-19. While vaccines do not offer 100% protection against COVID-19 infection, they can still partially defend against infection. Vaccines remain effective at protecting from COVID-19-caused serious illness, hospitalization and death.
Our fact-check sources:
- USA TODAY, Nov. 17, 2021, Fact check: Vaccines protect against contracting, spreading COVID-19
- USA TODAY, Jan. 21, Booster shots 90% effective at preventing omicron hospitalizations, CDC data shows: COVID-19 updates
- USA TODAY, Jan. 9, Is the Omicron surge nearing an end? Your questions about Omicron answered
- USA TODAY, Jan. 10, US COVID-19 map: Tracking cases and deaths
- USA TODAY, Jan. 11, Omicron in the Crosshairs
- USA TODAY, Jan. 11, NY breakthrough infections grow sevenfold, but unvaccinated 13 times more likely to wind up in hospital: COVID-19 updates
- CNN, Aug. 6, 2021, Fully vaccinated people who get a Covid-19 breakthrough infection can transmit the virus, CDC chief says
- Kathleen Conley, Jan. 11, Email exchange with USA TODAY
- The New York Times, Dec. 19, 2021, Most of the World’s Vaccines Likely Won’t Prevent Infection From Omicron
- NBC Chicago, Jan. 10, Which Vaccine is Best Against Omicron? What We Know as Pfizer, Moderna Prepare New Shots
- Dr. David Dowdy, Jan. 11, Phone interview with USA TODAY
- Dr.Chris Beyrer, Jan. 11, Phone interview with USA TODAY
Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or electronic newspaper replica here.
Our fact-check work is supported in part by a grant from Facebook.