Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said this week health officials are starting to see “too many cases” again as a warning.
“Well-documented cases, which were infected, come back, exposure and re-infection after a relatively short period of time measured anywhere from weeks to several months,” he said. “
“So you have to be really careful that you’re not completely ‘immune’,” Fawcett said.
While it is possible to be re-infected with the virus, there are still questions scientists are working on to answer, including who is likely to be re-infected and how long antibodies protect people from other infections.
There are scientists A study of how long antibodies last
Researchers at the University of Arizona have discovered that antibodies that protect against infection can last at least five to seven months after infection.
With an epidemic less than a year old, it will take time before scientists get a clear picture of immunity.
“That said, we know that people who were first infected with the SARS coronavirus, the most similar virus to SARS-CoV-2, are still seeing immunity 17 years after the infection. One is, we expect antibodies to last at least two years, and that would be impossible in the short term, ”Dipt Bhattacharya, an immunobiologist at the University of Arizona Medical College of Medicine, told CNN.
Other studies, one from Massachusetts and the other from Canada, support the idea of long-running immunity.
What is unclear is how the second infection can affect any Covid-19 vaccine. The Nevada man experienced more severe symptoms during his second infection while the Hong Kong man had no obvious symptoms during his recurrence.
How severe the disease is can affect antibodies
Researchers are beginning to notice something else: People who struggle with illness have stronger immunity.
“There is a difference between asymptomatic people who had a very mild infection, those who do not have detectable antibodies seem to have a slightly larger number,” said Swaminathan of the WHO. “But everyone with moderate to severe disease has antibodies.”
Bhattacharya, from Arizona, roared in search of it.
“People sampled from the ICU have higher levels of antibodies than people with mild disease,” he said, adding that they did not yet know what that would mean for long-term immunity.
CNN’s Maggie Fox contributed to this report.