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Two new studies give encouraging evidence that COVID-19 may offer some protection against future infections. Researchers found that people who made antibodies to the coronavirus were much less likely to test positive again for six months and possibly longer.
The results bode well for vaccines, which cause the immune system to make antibodies – substances that attach to a virus and help kill it.
Researchers found that people with antibodies to natural infections were “at much lower risk … of the same kind of protection you would get from an effective vaccine” of contracting the virus again, said Dr. Ned Sharpless, director of the US National Cancer Institute.
“It’s very, very rare” to get re-infected, he said.
The institute’s study had nothing to do with cancer – many federal researchers have turned to coronavirus work due to the pandemic.
Both studies used two types of tests. One is an antibody blood test, which can persist for several months after infection. The other type of test uses nasal or other samples to detect the virus itself or fragments of it, suggesting a current or recent infection.
A study, published Wednesday by the New England Journal of Medicine, involved more than 12,500 health workers at Oxford University Hospitals in the UK. Of the 1,265 who initially had anti-coronavirus antibodies, only two tested positive for active infection within six months and none developed symptoms.
This contrasts with the 11,364 workers who initially did not have antibodies; 223 of them tested positive for infection within about six months.
The National Cancer Institute study involved more than 3 million people who had antibody tests at two private labs in the United States. Only 0.3% of those who initially had antibodies later tested positive for the coronavirus, compared with 3% of those who lacked such antibodies.
“It’s very gratifying” to see that the Oxford researchers saw the same reduction in risk – 10 times less likely to have a second infection if antibodies were present, Sharpless said.
His institute’s report was posted on a website scientists are used to sharing their research and is being reviewed in a major medical journal.
The results are “not a surprise … but they are truly reassuring as they tell people that immunity to the virus is common,” said Joshua Wolf, infectious disease specialist at the Children’s Research Hospital of St. Jude of Memphis, who played no part in either. study.
The antibodies themselves may not confer protection, they could just be a sign that other parts of the immune system, such as T cells, are able to fight off further exposure to the virus, he said. he declares.
“We don’t know how long this immunity lasts,” Wolf added. Cases of people having contracted COVID-19 more than once have been confirmed, so “people still need to protect themselves and others by preventing reinfection.
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The Associated Press’s Department of Health and Science receives support from the Department of Science Education at the Howard Hughes Medical Institute. The AP is solely responsible for all content.
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