Three cases show that people can catch COVID-19 twice.

Cleveland, OH-Researchers in different parts of the world have identified three cases of reinfection of patients with COVID-19, raising questions about vaccine and immunity development.

The cases under consideration occurred in Hong Kong, Belgium and the Netherlands.

It should be reassuring that the fact that only three cases of reinfection have been confirmed Dr. Robert Sarata, Infectious disease specialist at university hospital and medical director.

“Reinfections are rare,” said Sarata. “We still understand the dynamics of this virus.”

Hong Kong researchers are studying a 33-year-old Hong Kong person who was hospitalized for the first time in March when he caught COVID-19. He reportedly had a negative coronavirus test in mid-April.

The man tested positive the second time after returning to Hong Kong from a trip to Spain and the UK. This is a country where COVID-19 cases have recently recurred. Although he had no symptoms, he was hospitalized for surveillance.

Every time he was hospitalized, the doctor examined the virus in the blood of Hong Kong people. Tests suggested that the virus was mutated in the four months between infections, reports said.

“What we are learning about infections is that people get an immune response,” Maria Wankerkov, a World Health Organization infectious disease epidemiologist in Geneva, Switzerland, said Monday at a WHO news briefing. It was. “What is not completely clear yet is how strong the immune response is and how long it lasts.”

The Belgian case was a woman in her fifties, who was infected with another coronavirus strain in March and June. According to Reuters. The Dutch patient was an elderly with weakened immunity and was reinfected with another strain of virus.

According to Sarata, most people who have recovered from COVID-19 are protected from a second outbreak, how long the antibodies to the coronavirus persist in their bodies, or how much against a second infection. Researchers are not convinced that protection will be provided.

“There are too few cases (reinfections) to generalize,” he said.

Those who have recovered from COVID-19 should continue to wear masks and wash their hands to increase their social distance, he said.

Flu strains change with the season of the flu, but we do not know if the coronavirus changes frequently. Dr Christine Engrund, Part of the Cleveland Clinic Infectious Diseases Division.

“I don’t think we can do that,” Englund said.

If the coronavirus has the widespread ability to reinfect people, it may make it difficult to achieve herd immunity, Sarata said. Collective immunity occurs when a sufficient number of people are protected from the disease and those who are not vaccinated.

He said that 45% to 60% of the population would need to acquire COVID-19 and produce protective antibodies against it to reach that threshold.

According to Salata, future COVID-19 vaccines may need to be given as a booster or as an annual influenza vaccine.

According to the hospital system, UH will participate in approximately 120 clinical trial sites worldwide, with up to 30,000 participants co-registering to test the potential of the COVID-19 vaccine. Sarata is the chief researcher at the trial, It will start next week.

Three reinfections also question the efficacy of convalescent plasma and monoclonal antibodies as COVID-19 treatments.

Convalescent plasma A concentrated dose of antibody extracted from the blood of patients recovered from COVID-19. Doctors will isolate these antibodies and inject them into another COVID-19 patient to help fight the disease until the patient is able to make their own antibodies.

this week, Food and Drug Administration We issued an emergency permit to use convalescent plasma for the treatment of patients admitted with COVID-19.

Monoclonal antibodies are manufactured in the lab to mimic the body’s natural defenses against disease.

Dr Envund describes how they could be affected as COVID-19 reinfection becomes more common, as there are no randomized controlled trials testing convalescent plasma and monoclonal antibodies. Said it was difficult.

“There is no evidence that (convalescent plasma and monoclonal antibodies) work,” she said.