As more and more people get vaccinated against COVID-19, the more scientists and doctors are learning about how effective the vaccines are in the real-world at controlling the spread of the virus.
People who have been vaccinated against COVID-19 do not appear to be able to carry or transmit the virus to others, the director of the Centers for Disease Control said, based on data from the large, real-world study of vaccinated people released this week.
“Vaccinated people do not carry the virus, don’t get sick, and that is not just in the clinical trials but it’s also in real world data,” CDC Director Dr. Rochelle P. Walensky said on The Rachel Maddow Show on Tuesday.
That data came from the CDC study released Monday of just under 4,000 heath care workers, police, firefighters and other essential workers who received one of the two mRNA vaccines between Dec. 14 and March 13. The vaccinated people were tested for COVID-19 every week for 13 weeks to monitor how effective the Pfizer and Moderna vaccines were in daily life in the U.S., outside of a clinical trial.
Testing showed that the risk of infection went down by 90% two weeks or more after they received their second dose, and even just one dose was 80% effective after two weeks. Of the 2,479 people in the study who were fully vaccinated, just three contracted COVID-19, which is in line with the vaccine’s efficacy. In comparison, the CDC also tracked 994 people who were not vaccinated, and 161 contracted COVID-19. No one in the study died.
Additionally, health experts had been concerned that vaccinated people could carry COVID-19 asymptomatically and potentially unknowingly transmit the virus to unvaccinated people. But none of the vaccinated people tested positive for COVID-19 during the 13 weeks, so they did not carry the virus.
The study data does not, however, mean that vaccinated people can stop wearing masks, health experts emphasized. There is still a risk that they could get COVID-19, especially with several faster-spreading variants now circulating through the U.S.
“We can kind of almost see the end,” Walensky said. “We’re vaccinating so fast … And yet on the other side, I’m watching the cases tick up. I’m watching us have increased numbers of hyper-transmissible variants. I’m watching our travel numbers tick up, and the sense is, I have seen what it looks like to anticipate the oncoming surge. And what I really would hate to have happen is to have another oncoming surge just as we’re reaching towards getting so many more people vaccinated.”
That’s good to know!