Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said this week that health officials are beginning to see “a number of cases” reported as reinfections.
“Well-documented cases,” he said, “of people who became infected, after a relatively short period of time anywhere from weeks to several months, come back, get exposed, and become infected again.”
“So you really have to be careful that you̵
Although it is possible to be re-infected with the virus, there are still questions that researchers are working to answer, including who is more likely to be reinfected and how long antibodies protect humans from another infection.
Scientists are study how long antibodies last
Researchers from the University of Arizona found antibodies that protect against infection can last for at least five to seven months after a Covid-19 infection.
With the pandemic under a year old, it will probably take time before scientists can get a clear picture of immunity.
“That said, we know that people who became infected with the first SARS coronavirus, which is the most similar virus to SARS-CoV-2, still see immunity 17 years after infection. If SARS-CoV-2 is something as the first one, we expect antibodies to last at least two years, and that would be unlikely for anything much shorter, ”Deepta Bhattacharya, an immunobiologist at the University of Arizona College of Medicine, told CNN earlier.
Other studies, one out of Massachusetts and the other out of Canada, supported the idea of long-term immunity.
What is unclear is how other infections can affect any Covid-19 vaccine. The Nevada man experienced more critical symptoms during his second infection, while the Hong Kong man had no obvious symptoms during his reinfection.
The severity of the disease can affect antibodies
There is something else researchers are beginning to notice: People who have a tougher battle with the disease tend to have a stronger immune response.
“There is a difference between people who are asymptomatic who had a very mild infection. There seems to be a slightly larger number of them who do not have detectable antibodies,” says Swaminathan, with WHO. “But almost everyone who has moderate to severe illness has antibodies.”
Bhattacharya of Arizona reiterated this finding.
“The people who were discharged from the ICU had higher levels of antibodies than people who had a milder disease,” he said, adding that he did not yet know what that would mean for long-term immunity.
CNN’s Maggie Fox contributed to this report.