Researchers have recently found that the antibodies made by the immune system in order to fight COVID-19 may not exist much longer in people with mild illness.
However, the researchers also said that it doesn’t mean protection also is gone or that it won’t be possible to develop an effective vaccine.
As per reports, the researchers had studied about the protection provided by the antibodies in 34 persons and most of them were also found to have mild illness.
Among the 34 persons enrolled for the study, 30 patients were diagnosed with COVID-19 and four housemates presumed to have the disease.
The researchers, from the University of California, found that the antibodies had a half-life of 73 days, which means that half of them would be gone after that much time.
The new study, which was published in the New England Journal of Medicine on Tuesday, also reported findings consistent with that of a previous report from China which had suggested that antibodies quickly fade.
“Our findings raise concern that humoral immunity against SARS-CoV-2 may not be long lasting in persons with mild illness, who compose the majority of persons with Covid-19,” the study said.
“Still, the results call for caution regarding antibody-based immunity passports, herd immunity, and perhaps vaccine durability, especially in light of short-lived immunity against common human coronaviruses,” it added.
“Infection with this coronavirus does not necessarily generate lifetime immunity,” but antibodies are only part of the story, said Dr Buddy Creech, an infectious disease specialist at Vanderbilt University.
The immune system remembers how to make fresh antibodies if needed and other parts of it also can mount an attack, he said.
According to Creech, B cells develop a memory on how to churn antibodies so they know how to do that again if needed.
“They would get called into action very quickly when there’s a new exposure to the virus. It’s as if they lie dormant, just waiting,” he said.
Other white blood cells called T cells also are better able to attack the virus the next time they see it, Creech said.