[ad_1]
A man from the US state of Nevada has become one of the few people in the world who has contracted COVID-19 twice.
The 25-year-old, who has not been publicly identified, had no known health conditions or immune problems that would have made him particularly vulnerable to the virus.
Doctors said the man needed hospital treatment after his lungs deteriorated during the second infection, which was much worse than the first.
According to the study published in The Lancet Infectious Diseases, the man experienced the first symptoms (sore throat, cough, headache, nausea and diarrhea) on March 25.
She tested positive for the first time on April 18 and her symptoms resolved on April 27.
On May 9 and 26, he tested negative, but on May 28 he again presented symptoms, this time such as fever, headache, dizziness, cough, nausea and diarrhea.
On June 5, he tested positive for the second time and went on to suffer from a lack of oxygen in his blood and difficulty breathing.
The scientists said that the genetic codes of the two diseases were different, meaning that this was not a case where the first infection was inactive and then reappeared.
The study said the case was the first known COVID-19 reinfection in North America, with other individual cases reported in Hong Kong, the Netherlands, Ecuador and Belgium.
Patients in those locations did not show an increase in severity of symptoms the second time, with the exception of the patient in Ecuador.
It was unclear what caused the second infection in Nevada. The study suggested that one possibility was a “very high dose of virus (that) could have led to the second instance of infection and induced a more serious illness.”
Another suggestion was that the reinfection was caused by a “version of the virus that was more virulent, or more virulent in the context of this patient.”
A third possibility was an “antibody-dependent enhancement mechanism … a means by which specific Fc-bearing immune cells become infected with virus by binding to specific antibodies.”
The study authors said: “Previous exposure to SARS-CoV-2 may not guarantee full immunity in all cases.
“All people, whether they have previously been diagnosed with COVID-19 or not, should take the same precautions to avoid infection with SARS-CoV-2.
“The implications of reinfections could be relevant for vaccine development and application.”
Reinfections also have implications for ideas like herd immunity: The body was supposed to learn to fight the virus during an initial infection, meaning that subsequent infections would be milder or even without symptoms.
But it also shows that even after nearly 38 million confirmed cases and more than one million deaths from the virus worldwide, scientists are still learning about the subject of COVID immunity.
