Cases of coronavirus reinfection are so far uncommon. Studie v The Lancet wonders to what extent immunity can be established against coronavirus. The twice-infected man is from Nevada and has no chronic health problems or weakened immunity, which would place him at risk in case of coronavirus infection.
The first symptoms, including cough, headache, sore throat, diarrhea and nausea, manifested on March 25. He had his first positive test for coronavirus on April 18. All symptoms disappeared on April 27 and he subsequently had two negative tests on May 9 and 26.
However, he was tested for the second time on June 5, after showing symptoms again on May 28, this time the disease was accompanied by shortness of breath and insufficient oxygenation of the blood.
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According to the researchers, the man is more likely to become infected twice than to have his coronavirus reactivated. They came to this conclusion on the basis of different genetic codes of the virus collected in April and June.
The first infection may not help the second
“Our findings suggest that a previous infection may not necessarily protect against infection in the future,” said Dr. Mark Pandori of the University of Nevada. “The possibility of re-infection can significantly affect our understanding of immunity to covid-19,” he added.
He stressed that even people who have recovered from a coronavirus infection should continue to keep their distance, wear veils and wash their hands.
Researchers are trying to find out more about coronavirus immunity. Will anyone who gets infected get it? Even people with mild symptoms? How long is a person protected from reinfection? These are important questions, as the answers to them may have major implications for the vaccination program or for determining whether collective immunity can be established against coronavirus.
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Of the more than 37 million infected worldwide, recurrent covid-19 has been reported rarely. In addition, cases of reinfection reported in Hong Kong, the Netherlands or Belgium were not accompanied by more severe symptoms than the first infection. However, there have been cases, for example in Ecuador, where the second infection had more severe symptoms, similar to a man in Nevada.
Any co-infection with coronavirus is expected to be milder than the first, as the body learns to fight the virus. It is still unclear why the course of the disease in a Nevada patient was more severe during the second infection. A possible explanation is that in the latter case he received a larger viral load.
Another possibility is that his immune response at the first infection worsened the course of the second. Such cases have been reported, for example, in dengue fever, where antibodies raised in the body against one strain of dengue virus have caused problems if a person has become infected with another strain.
Paul Micter, a microbiologist at the University of East Anglia in the UK, described the findings of the 25-year-old American’s study as very worrying, especially since he became infected twice in a very short time. At the same time, however, Hunter noted that there are very few such cases and it is too early to draw conclusions that would guide the immunization program. “These findings show that we still do not know enough about the immune response to this infection,” he concluded.
Death after reinfection
Dutch scientists even announced on Monday the first proven casewhen someone died after the second coronavirus infection. She was an 89-year-old woman being treated for a rare form of cancer. In the first half of the year, she was hospitalized for five days when she developed symptoms of covid-19, and the infection was later confirmed by tests.
Two months later, just after the start of new chemotherapy, these symptoms reappeared. Tests showed coronavirus, but not antibodies. “On the eighth day after hospitalization, her condition began to deteriorate, she died two weeks later,” the researchers said.
Doctors had samples of the two infections at their disposal and found that the genetic samples of the virus were different – meaning that it was not just a reactivation of the virus in the body, but probably a new infection. So far, the researchers have described about thirty cases of reinfection, although there are probably many more – but in all previous cases, the patient was cured.
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