Why can people recover from re-infection with nCoV?

Medical experts warn that antibodies in recovering people are not strong enough or persist for a long time to help them become immune to nCoV in subsequent visits.

On February 26, Japanese health authorities reported the first case of Covid-19 reinfection in the country. A guide in Osaka first tested positive for nCoV in late January and was discharged from the hospital three weeks ago after showing signs of recovery. But when the woman returned to the hospital for a sore throat and chest pain, the nCoV tests were again positive.

Graphics corona virus simulation.(Photo: Time).

Cases of re-infection of nCoV in recovering people also occur in China. On February 21, the Chengdu City Public Health Medical Center, Sichuan Province, China, confirmed a re-infected Covid-19 patient after nearly 10 days of discharge. On February 28, the Guangdong Centers for Disease Control and Prevention (CDC) recorded about 14% of patients removed from nCoV and discharged in the province to test positive for nCoV in the following test. There is no clear conclusion on the cause or whether these patients continue to spread the disease to others, said Tong Thiet, deputy director of CDC Guangdong.

Zhan Qingyuan, director of the prevention and treatment of pneumonia at China-Japan Friendship Hospital, warned that the recovering person could get re-infected with nCoV."There is still a risk of reinfection for patients who have recovered. Their bodies will produce antibodies. However, in some individuals, antibodies do not last long , " Mr. Zhan said.

The corona virus family includes the virus that causes SARS, MERS and the common cold. Mostly spread through upper respiratory tract. When the virus enters the body, it tries to attach to and invade the host cell. In response, the human immune system produces antibodies, proteins that recognize and kill viruses. That is how people become immune to certain diseases. For example, children with chickenpox will be immune to the disease in adulthood. Vaccine is another way to develop immunity.

"With many infectious diseases, a person can develop immunity to a specific strain of the virus after infection," explains Amira Roess, professor of global health and epidemiology at George Mason University. "Normally, he or she will not fall ill at subsequent exposure to the pathogen."

But with nCoV, doctors think that the antibodies that patients make are not strong enough or exist long enough to help them fully immune to the disease in the long run . Once infected, the virus can become inactivated with very few symptoms, then the condition will become serious if the virus finds its way into the lungs, said Philip Tierno, a professor at the University of New York School of Medicine. know.

According to Professor Samuel McConkey, vice rector of the Royal College of Surgery in Ireland, Covid-19 could re-infect because it has happened to previous corona virus strains. The occurrence of re-infections indicates that some people may not develop natural immunity.

"The concern is that Covid-19 can spread around the world in March, April, and May, and come back three months later because we are not protected by immunity after the first infection. will continue to circulate for years until we find the technology to control it, " McConkey said. He also emphasized that the possibility of re-infection could make it difficult to produce effective vaccines against nCoV.

However, Patrick Mallon, professor of bacterial diseases at the University of Dublin, Ireland, thinks that people will develop immunity to some degree, similar to that of swine flu (H1N1). Mallon pointed out that the swine flu epidemic once led to a high number of infections and deaths when it first appeared. But in the following circulation, this disease is no longer serious.

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