Yes, you can get COVID-19 again: what you need to know

The patient’s first infection was diagnosed on March 26, 2020 and included three days of cough, sore throat, fever and headache.

He was hospitalized on March 29 and was released on April 14 with two negative diagnostic tests.

The man had a second positive reaction, four and a half months after the first infection, after returning from Spain to Hong Kong.

He again tested positive for SARS-CoV-2, but the second infection remained asymptomatic throughout the course.

By sequencing the virus behind each infection, the researchers determined that the infection was caused by different variants of the new coronavirus.

It’s said to think of sequences like fingerprints Dr Yvonne MaldonadoHead of Pediatric Infectious Diseases Department, School of Medicine, Stanford University, California.

“All viruses are mutated. These are ways to distinguish that this was a new infection, not a long-term release from a previous infection,” he explained. Dr. Amesh Adalha, A doctor of infectious diseases and a senior researcher at the Center for Health and Safety at Johns Hopkins University.

This is the first case of documented SARS-CoV-2 reinfection, but health professionals suspect that patients are not the only ones already twice infected with the new coronavirus.

“Probably others could have been infected twice, but there was a special case with a rare and very characteristic variant of the virus, and a complete sequence of both viruses to make sure it could be distinguished.” Benjamin Neumann, PhD, Virologist, Texas A & M University-Head of the Biology Department of Texarkana.

Initial evidence suggests that people have some degree of protection after recovering from a SARS-CoV-2 infection.

1 To report Looking at the outbreaks that occurred on the fishing vessels, we found that several sailors who had previously tested positive for the new coronavirus antibody were not reinfected.

another Investigation An assessment of 34 people diagnosed with COVID-19 found that protective antibodies did not last too long and could decline in as little as 3 months.

Neumann emphasizes that we have not dealt with this coronavirus for a long time, so scientists have not yet revealed what kind of long-term immunity people have.

According to Neumann, immunity to other coronaviruses usually lasts about a year.

According to Maldonado, it is shorter (6 months) or longer (2 years).

“This is just one case, but it suggests that immunity to SARS-CoV-2 from the perspective of other coronaviruses should be considered. Rapid reduction of antibodies and reinfection are common. “Neuman said.

Note that this one case study is likely not applicable to the general public. It is unclear whether reinfection is common or rare.

“It’s very difficult to extrapolate from a case study of one patient who has not been published in a peer review or medical journal,” said Adalja.

According to Newman, the amount of white blood cells and antibodies varies greatly depending on the sick person, so the length of immunity may vary from person to person.

In general, sick people tend to mount larger immune responses that last longer. Maldonado says the immunity of people with mild infections declines rapidly.

This is common with other coronavirus reinfections, but Adalya is not surprised that the patient was asymptomatic for the second time.

Researchers suspect that the first infection may stimulate a person’s immunity to fight a second infection.

“Other parts of the immune system that weren’t identified at the time, perhaps memory B cells or T cells, can help remember the first infection and clear the second,” Neuman said. It was

According to Maldonado, viruses such as rotavirus and polio can lead to multiple infections, but the severity of subsequent illnesses is less.

“In general, the second and third infections tend to be less severe, which may be related to the immune response. But I’m not sure how it works,” Maldonado said. Told.

The question is whether this will tolerate SARS-CoV-2, or only certain mutants or mutations. (SARS-CoV-2 has not yet been significantly mutated, but it is always possible.)

Early results from clinical trials of vaccines suggest that vaccines are less immune than infections, according to Neuman.

Further testing is needed to determine the level of immunity the vaccine produces, but Neumann says it can reinfect several months after vaccination.

In that case, people may need to take booster shots, says Adalja.

With a vaccine like the measles vaccine, you only need to give it once and you’ll be protected for most of your life, says Maldonado, who handles poliovirus.

However, it does not apply to all viruses. Polio, for example, can have multiple infections after being vaccinated. Paralytic polio is unlikely to occur, but it can lead to reinfection.

The immunity achieved by a particular vaccine weakens over time. This means that people who have been vaccinated may eventually develop an infection.

Also, if reinfection is mild or asymptomatic, there is a tendency, but it can spread the virus to people who have never been infected.

Diseases can typically be eradicated when most populations are immune to it-a concept called herd immunity.

But Neumann said most scientists in the field of coronavirus feel that the new coronavirus may not be able to immunize herds.

According to Neuman, if people lose protective antibodies in just a few months, it can be nearly impossible to achieve herd immunity, regardless of the number of people infected with SARS-CoV-2. ..

However, many factors are involved and antibodies alone cannot determine a person’s ability to fight off subsequent infections.

“[It] All people depend on how contagious the second infection is, and if all the second infections are mild, exposure of the population reduces the risk of developing serious illness ..

As with all cases of coronavirus and COVID-19, more time and research is needed to understand the threat of reinfection and its impact on vaccine and herd immunity.

“It’s learning very quickly, given that the virus hasn’t existed around the world for a year,” Maldonado said.

A 33-year-old man in Hong Kong had a second SARS-CoV-2 infection just four and a half months after recovering from the first.

The anecdote about a potential reinfection spread recently, but this is the first recorded case of a SARS-CoV-2 reinfection.

Researchers want to determine if reinfection is a common or rare event to better understand how it affects vaccines and herd immunity.