Scientists are reporting worrying signs that some recent mutations in the virus that causes COVID-19 may modestly limit the effectiveness of two current vaccines, although they emphasize that the vaccines still protect against the disease.
The researchers expressed concern on Wednesday about preliminary findings, largely because they suggest that future mutations could harm vaccines. The research tested coronaviruses from the UK, 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 and more limited study released on Wednesday gave encouraging news about protecting a vaccine against some of the mutations.
One way vaccines work is to stimulate the immune system to produce antibodies that prevent the virus from infecting cells. The Rockefeller researchers took blood samples from 20 people who received the Moderna or Pfizer vaccine and tested their antibodies against various virus mutations in the laboratory.
With some, the antibodies did not work as well against the virus – the activity was one to three times less, depending on the mutation, said study leader Dr. Michel Nussenzweig de Rockefeller.
“It is a small difference, but it is definitely a difference,” he said. The antibody response “is not so good” in blocking the virus.
Previous research has established that the two vaccines are about 95% effective in preventing COVID-19 disease.
The latest findings were published on 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 scientific coverage by The Associated Press. The university applied for a patent related to its work.
Coronavirus has become 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 have emerged in the UK, South Africa and Brazil appear to spread more easily and scientists say this will lead to more cases, deaths and hospitalizations. The new variants do not appear to cause more serious illnesses, but their ability to reduce vaccines is a concern.
E. John Wherry, an immunology expert at the University of Pennsylvania, said that Rockefeller scientists are “among the best in the world” in this work and their results are worrying.
“We don’t want people to think that the current vaccine is out of date. This is absolutely not true, ”he said. “There is still immunity here … a good level of protection,” but the mutations “actually reduce how well our immune response is recognizing the virus.”
The news comes at “a really important moment in the pandemic,” said Dr. Buddy Creech, a vaccine expert at Vanderbilt University,
“We have an arms race between vaccines and the virus. The slower we launch the vaccine worldwide, the more opportunities we will give this virus to escape ”and develop mutations, he said.
Dr. Matthew Woodruff, an immunology researcher at Emory University, agrees.
“This is going to be a kind of slow evolutionary walk. We will have to have tools that develop slowly with it, ”like treatments that offer combinations of antibodies instead of one, he said.
Dr. Drew Weissman, a scientist at the University of Pennsylvania whose work helped lead to vaccines Moderna and Pfizer, said the antibody findings are worrying, but noted that vaccines also protect in other ways, such as stimulating responses from other parts of the system immune. The new work involved just 20 people and not a wide range of ages or races, “and it all matters” in how generalizable the results are, he said.
On Wednesday, Pfizer and its German partner BioNTech reported a second round of reassuring findings about their vaccine against one of the variants.
Earlier this month, Pfizer and researchers at the University of Texas Medical Branch said the vaccine remained effective against a mutation called N501Y of new variants found in the UK and South Africa. Likewise, there was no sign of a problem when they tested some additional mutations.
The most recent work tested all mutations of the UK variant at once, instead of one by one. Tests of 16 vaccinees showed no major difference in the antibodies’ ability to block the virus, the researchers said in a report.
Pfizer did not immediately comment on Rockefeller’s findings, but its scientific director, Dr. Philip Dormitzer, said earlier that the next steps include testing the vaccine against additional mutations found in the South African variant.
Moderna and AstraZeneca, which makes a different type of COVID-19 vaccine used in some countries, have also been testing how their vaccines resist different mutations.
If the virus eventually mutates enough that the vaccine needs to be adjusted – just as flu vaccines are changed most years – adjusting the prescription would not be difficult for vaccines made with the latest technologies. The Pfizer and Moderna vaccines are made with a part of the virus’s genetic code that is simple to change.
It is an “illusion” to believe that first generation vaccines will be sufficient, or that vaccines alone will solve our problems, said Mayo Clinic vaccine expert Dr. Gregory Poland.
“We are shooting ourselves in the foot, allowing full transmission of this virus” and not taking “common sense” measures, such as forcing the use of a mask as some other countries are doing, he said.
“How can bars and restaurants get crowded? It’s like ‘what pandemic?’ We harvest the seeds we plant, “he said.
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Medical writer Lauran Neergaard contributed to the report.
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The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.