(p. A8) Nearly 83 million Americans have received at least one dose of a Covid vaccine, and it’s unclear just how many of them will have a “breakthrough” infection, though two new reports suggest the number is very small.
One study found that just four out of 8,121 fully vaccinated employees at the University of Texas Southwestern Medical Center in Dallas became infected. The other found that only seven out of 14,990 workers at UC San Diego Health and the David Geffen School of Medicine at the University of California, Los Angeles tested positive two or more weeks after receiving a second dose of either the Pfizer-BioNTech or Moderna vaccines. Both reports, published on Tuesday [March 23, 2021] in the New England Journal of Medicine, show how well the vaccines work in the real world, and during a period of intense transmission.
. . .
Only some of the virus-positive health workers in the California study showed symptoms, . . ., and they tended to be mild, suggesting that the vaccines were protective. That echoes data from the vaccine trials indicating that breakthrough infections were mild and did not require hospitalizations. Some people had no symptoms at all, and were discovered only through testing in studies or as part of their medical care.
For the full commentary, see:
(Note: ellipses, and bracketed date, added.)
(Note: the online version of the commentary has the date March 23, 2021, and has the title “Vaccinated People Can Get Covid, but It’s Most Likely Very Rare.”)
The study discussed above is:
The NEJM articles mentioned above are:
Keehner, Jocelyn, Lucy E. Horton, Michael A. Pfeffer, Christopher A. Longhurst, Robert T. Schooley, Judith S. Currier, Shira R. Abeles, and Francesca J. Torriani. “Sars-Cov-2 Infection after Vaccination in Health Care Workers in California.” New England Journal of Medicine (March 23, 2021).