American doctors, who have observed cases of the second wave of coronavirus infection in those who had previously been ill with COVID-19, believe that the reason may be either re-infection against the background of weak immunity, or reactivation of the virus remaining in the body. The results of the study are published in the journal BMJ Case Reports. reports zakon.kz with reference to RIA Novosti.

Cases of re-infection with COVID-19 are relatively rare, and scientists cannot yet say for sure whether they are associated with re-infection or with the prolonged presence of the same virus in the body.

American researchers from the Yale University School of Medicine described a case where a person who recovered from COVID-19, after four months of no symptoms and a series of negative PCR tests, fell ill again.

The first time a 40-year-old man was admitted to hospital in April 2020. On admission to the hospital, he had difficulty breathing, accompanied by wheezing, caused by a disruption in the air flow known as stridor.

It is noted that in the patient’s history, there was a whole set of aggravating factors – type 2 diabetes, insufficient activity of the thyroid gland and obesity. At the hospital, he developed respiratory distress and was prescribed mechanical ventilation, anticoagulants, and other drugs used to treat COVID-19.

During the two months spent in the clinic, the man developed serious complications: hospital-acquired methicillin-resistant Staphylococcus aureus infection, gastrointestinal bleeding, mechanical ventilation-associated pneumonia and renal failure. But in the end he recovered and was discharged.

In the next three months, the patient passed tests for coronavirus three times, and they were all negative. Four months later, in August 2020, another PCR test showed a positive result for SARS-CoV-2, and two weeks later the man was hospitalized with shortness of breath and stridor, after he had several attacks of suffocation at home. This time the illness was much easier, and the patient stayed in the hospital for only a week.

The man explained to the doctors that during the entire time after the first hospitalization, he practically did not communicate with anyone except close relatives, none of whom had symptoms of COVID-19 or positive test results.

The US Centers for Disease Control and Prevention (CDC) writes in its guidelines that a positive smear test for SARS-CoV-2 within 90 days of the initial infection is more indicative of a sustained shedding of the virus than a reinfection. But since it took significantly longer after the initial infection, the researchers concluded that their patient had two separate episodes of infection, but in the second case, the disease was mild due to residual immunity from the first severe infection.

As the COVID-19 pandemic evolves, reports are emerging showing that SARS-CoV-2 may be reinfected, so a positive SARS-CoV-2 RNA test does not necessarily indicate persistent shedding of the virus over a long period of time, the authors of the article write. …