"The observation [showed] a fairly rapid decrease," he told the newspaper referring to his antibody levels. "By the end of the third month from the onset of the disease, they ceased to be determined."
He then decided to get reinfected to see how his body responded. He did this by spending time with patients with coronavirus, without wearing a mask. Every two weeks he was tested to see if he had been reinfected.
Six months after his initial illness, "protection fell," he said. He became ill for a second time, testing positive for the disease. Over the course of the second infection, he was hospitalized. He suffered from a high temperature, lost his sense of smell and X-rays showed pneumonia. "The pain was more severe than the first time," he told Komsomolskaya Pravda.
There are a number of problems with Chepurnov's experiment. Because his first case of COVID-19 was only found via antibodies, it is difficult to determine whether he suffered from two different strains of the virus. This is required to confirm a person has been reinfected with SARS-CoV-2, rather than the original virus reemerging in the body. He also points out, his reaction may not be the same as other people. Far more cases of reinfection will need to be studied before any conclusions are drawn about immunity.
Chepurnov said his own experiment is a warning against a herd immunity approach. He also said it has implications for a vaccine, suggesting multiple doses will be required. As a result, Chepurnov thinks the virus will be with us for many years to come.