While the coronavirus raised many questions during its several months of global spread, some questions seem more puzzling than others, like whether or not a previously infected individual is immune or at risk for reinfection. There were theories of second infections of COVID-19, but researchers at the University of Hong Kong have confirmed re-infection fears.

According to a study published in the international medical journal Clinical Infectious Diseases on Monday, researchers documented that a young resident from Hong Kong had recovered from COVID-19 infection and was discharged from a hospital in April, but then tested positive again after returning from a trip abroad in August. Researchers found that the patient had contracted a different strain of the novel coronavirus, meaning that he was infected from a mutation of the virus. The researchers noted that with the second infection the patient remained asymptomatic.

The findings indicate that the coronavirus, which has infected over 23 million and killed more than 800,000 people globally, may continue to spread without intervention because herd immunity may not be possible.

"Many believe that recovered COVID-19 patients have immunity against re-infection because most developed a serum neutralizing antibody response," a press release about the study stated. "However, there is evidence that some patients have waning antibody levels after a few months."

Treatment Update

Over the weekend, the U.S. Food and Drug Administration granted the an emergency use authorization for use of convalescent plasma in the treatment of hospitalized COVDI-19 patients. However, convalescent plasma, or antibodies from recovered COVID-19 patients, has not yet been proven to work on wide groups of people with a randomized, controlled clinical trial, what health officials consider the "gold standard." The federal agency stated that it was reasonable to believe that the treatment may be effective in treating COVID-19 patients due to its positive track record with other diseases, stating the known and potential benefits outweigh potential risks.

One study on the use of convalescent plasma as a coronavirus treatment of 35,000 patients by the Mayo Clinic and sponsored by the National Institutes of health concluded that the plasma may help reduce mortality in some hospitalized patients. However, the study didd not have a comparison group with patients only receiving standard care, making it difficult to prove that the treatment works.

Nevertheless, President Donald Trump praised convalescent plasma as a "breakthrough," but other health officials remain wary of the potential treatment. The World Health Organization's chief scientist Dr. Souma Swaminathan stated during a press briefing on Monday that the global agency has been testing the use of plasma as a treatment.

"We do ongoing meta-analyses and systematic reviews to see where the evidence is shifting or pointing, and at the moment it's still very low-quality evidence. So we recommend that convalescent plasma is still an experimental therapy," Swaminathan stated, quoted by CNBC. "It should be evaluated in well-designed, randomized, clinical trials."