Some patients recovered from the Covid-19 virus, and all the results of their tests were negative, but later the test result turned positive. Corona virus infection is similar to common cold cases, which usually leads to the creation of immunity in the patient, so what is different with this virus?
A man in his 70s is an early and stark example of the kind of recovery that has bothered doctors. The person was placed in isolation in a hospital in the Japanese capital, Tokyo, last February after being diagnosed with the Corona virus.
According to the Japanese broadcaster NHK, he recovered and returned to his normal life to the extent that he was taking public transportation. But a few days later he fell ill again, developed a fever, and returned to the hospital. The surprise for him and the doctors was that the result of his analysis of the virus came back positive. And this man is not the only case of this kind in Japan, it happened to others, although they are a minority, but their number draws attention, so why does this happen?
Luis Inguanes, a virologist at the Spanish National Institute of Biotechnology, tells the BBC that 14% of patients who have recovered from Covid-19 have had it again. He believes that they are not infected again, but that it is a “reflux” case of the virus.
“My vision is among other possible visions, and in general, infection with this virus creates immunity in people, but the reaction of the immune system is not very strong in some, and when the reaction of the immune system slows down, the remnants of the virus latent in the body return again,” he explains. The virus lives in the body and some types can stay in the body for three months or more.
“When some people’s virus test results change from positive to negative, it is assumed that they have developed immunity to the virus, but some of it remains dormant in tissues that have not been exposed to the body’s defenses like other organs,” says Ingwanes.
Another thing that interests scientists about COVID-19 is the short time between recovery and positive testing of a patient again.
“The answer is that we simply don’t know about the possibility of re-infection yet because we don’t have an antibody test for infection,” said John Cohen, Professor Emeritus of Infectious Diseases at Brighton and Sussex Medical College.
“However, it is very likely, based on other viral diseases, that once a person is infected, they will generally be immune and will not get them again. But there will always be the odd exception, and that is certainly a reasonable expectation.”