Virus mutations may dampen vaccine efficacy
Scientists are reporting troubling signs that some recent mutations of the virus that causes COVID-19 may modestly curb the effectiveness of two current vaccines, although they stress that the shots still protect against the disease.
Researchers expressed concern Wednesday about the preliminary findings, in large part because they suggest that future mutations could undermine vaccines. The research tested coronaviruses from the United Kingdom, South Africa and Brazil, and was led by Rockefeller University in New York with scientists from the National Institutes of Health and elsewhere.
A different, more limited, study out Wednesday gave encouraging news about one vaccine’s protection against some of the mutations.
One way vaccines work is to prompt the immune system to make antibodies that block the virus from infecting cells. The Rockefeller researchers got blood samples from 20 people who had received either the Moderna or Pfizer vaccine and tested their antibodies against various virus mutations in the lab.
With some, the antibodies didn’t work as well against the virus — activity was one-to-threefold less, depending on the mutation, said the study leader, Rockefeller’s Dr. Michel Nussenzweig.
“It’s a small difference, but it is definitely a difference,” he said. The antibody response is “not as good” at blocking the virus.
Earlier research established that the two vaccines are about 95% effective in preventing COVID-19 illness.
The latest findings were posted late Tuesday on an online website for researchers and have not yet been published in a journal or reviewed by other scientists. Nussenzweig is paid by the Howard Hughes Medical Institute, which also supports science coverage at the Associated Press. The university has applied for a patent related to his work.
The coronavirus has been growing more genetically diverse and scientists say the high rate of new cases is the main reason. Each new infection gives the virus a chance to mutate as it makes copies of itself.
Recent variants, or versions, of the virus that emerged in the U.K., South Africa and Brazil seem to spread more easily and scientists say that will lead to more cases, deaths and hospitalizations. The new variants do not seem to cause more serious disease, but their ability to eventually undercut vaccines is a concern.