Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases said this week health officials are starting to see “a number of cases” reported as recurrences.
“Well-documented cases,” he said, “” of infected people, after a brief short period of time measured anywhere from weeks to months are returned, exposed and infected again. “
“So you really have to be careful that you are not completely‘ immune, ’” Fauci said.
While it is possible to be infected again with the virus, scientists are still working on questions to answer, including who is more likely to be reinfected and how long the antibodies protect humans from another infection.
Scientists are analyzes how long the antibodies last
Researchers from the University of Arizona found that antibodies that protect against infection can last for at least five to seven months after Covid-19 infection.
In pandemic under one year of age, it is likely that it will be a long time before scientists get a clear picture of immunity.
That being said, we know that people infected with the first SARS coronavirus, which is the most similar virus to SARS-CoV-2, still see immunity 17 years after infection. SARS-CoV-2 is similar to the first one, we expect the antibodies to last at least two years, and this is unlikely to be any shorter, “said Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine, previously told CNN.
Other studies, one in Massachusetts and the other outside of Canada, support the idea of long-term immunity.
What is not clear is how a secondary infection can affect any Covid-19 vaccine. The Nevada man experienced more critical symptoms in his second infection while the Hong Kong man had no obvious symptoms at the time of his recurrence.
How severe the disease can be is affected by antibodies
There are other things that researchers are beginning to notice: People with a poor immune system tend to have a stronger immune response.
“There is a difference between asymptomatic people, who have had a very mild infection, there seems to be a slightly larger number of those without noticeable antibodies,” Swaminathan, who is with the WHO, said. “But almost everyone with moderate to severe illness has antibodies.”
Bhattacharya, from Arizona, echoed that search.
“People sampled from the ICU have higher levels of antibodies than people with milder disease,” he said, adding that he does not yet know what this means for long-term survival. sick.
CNN’s Maggie Fox contributed to this report.