Two reports of so-called coronavirus infections – in which fully vaccinated people suffer from the disease – suggest that vaccines still provide strong protection against severe disease even in the face of variants.
The cases, detailed in the New England Journal of Medicine on Wednesday, were in two women from more than 400 fully vaccinated study participants who were tested for Covid-19 weekly. Both women developed mild cases of the disease and recovered quickly.
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The co-author of the study, Dr. Robert Darnell, a professor and senior physician at Rockefeller University in New York, said the two cases were not cause for alarm.
“They certainly didn’t have to be hospitalized,” he said. “They had cases at home of Covid-19.”
As the number of people completely vaccinated in the US increases, so do reports of infections discovered. Last Friday, the Centers for Disease Control and Prevention said it had received reports of about 5,800 infections discovered from more than 77 million people completely vaccinated.
Revolutionary infections can occur because no vaccine is 100% effective. Even so, such cases remain very rare.
CDC officials are collecting more data on discovery cases to determine if there are patterns among patients. Among the questions the agency asks is whether certain variants are more likely to play a role in discovery cases.
Both cases in the New England Journal of Medicine report were sequenced and it was found that both cases share certain mutations with variants first identified in the United Kingdom and New York. However, none of them contained all the mutations corresponding to these previously identified variants. (Virus variants can contain multiple mutations.)
However, experts warned that because the report included only two cases, it is too early to draw conclusions about which variants are most likely to lead to discovered infections.
One of the samples contained a mutation called E484K, which is also found in variants in South Africa, Brazil and New York and is believed to help the virus to some extent evade the body’s immune response.
Jeremy Kamil, a virologist at LSU Health Shreveport, said he was not surprised that the mutation was detected because lab data suggests it would play a role in the discovery.
“If you ask scientists what mutations you would expect to see in a revolutionary infection, I think the No. 1 answer you will get would be E484K,” said Kamil, who was not involved in the new study.
Also Wednesday, two studies published in the CDC’s weekly report on morbidity and mortality touched on infections found in nursing homes. A report identified 22 infections found in 78 nursing homes in the Chicago area that completely vaccinated nearly 15,000 residents and staff from December to March. In two-thirds of the cases found, the infections were asymptomatic, although several people developed mild to moderate symptoms, the report said. Two patients were hospitalized and one individual died.
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The second report focused on a Covid-19 outbreak at a Kentucky nursing home in March. Twenty-six residents and 20 employees tested positive, including 18 residents and four employees who were completely vaccinated. Case sequencing detected the same E484K mutation observed in New York cases.
However, those who had been vaccinated were still 87% less likely to develop symptoms than those who were not vaccinated.
“The results of this study are quite telling that vaccination has reduced the likelihood of infection and symptomatic disease in a high-risk population,” such as a nursing home, said Jason Kindrachuk, assistant professor of medical microbiology and infectious diseases. at the University of Manitoba in Winnipeg.
Similarly, the women described in the New England Journal of Medicine report also showed mild symptoms, said Kindrachuk, who was not involved in the new reports. “The vaccines did exactly what I expected from clinical trials and real-world data: they protected against severe disease.”
One of the patients in the report of the New England Journal of Medicine, a 51-year-old healthy woman, tested positive for Covid-19 on March 10, 19 days after the second dose of Moderna vaccine. She said she followed guidelines, including masking and social distancing, but developed symptoms, including sore throat, congestion and headaches. The day after the test, he lost his sense of smell. All her symptoms disappeared a week later.
The second patient, a 65-year-old woman with no risk factors for severe Covid-19, tested positive on March 17, 36 days after the second dose of Pfizer-BioNTech vaccine. She became ill two weeks after her unvaccinated partner was diagnosed with Covid-19.
Her symptoms include fatigue, sinus congestion and headache. As in the first case, her symptoms disappeared after only a few days.
While data from the CDC suggest that the infections found are rare, Darnell said it would be prudent for fully vaccinated people to be tested for Covid-19 if they develop disease-like symptoms.
“If you get sick after vaccination and it looks like it smells and sounds like Covid-19, it could be Covid-19,” he said.
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