As per media reports, dated August 25, 2020, a 33-year-old man fell prey to second SARS-CoV-2 infection after recovering from an initial bout in April in what scientists said was the first case showing that reinfection may occur within a few months. He was detected via airport screening on his return to Hong Kong from Europe. Since he was suffering from two different strains, genomic sequence analysis was used by researchers from the University of Hong Kong to prove the case. However, he did not develop any symptoms from the second infection, which might indicate that ‘subsequent infections may be milder.’ This is the world’s first incident where a patient after recovering, got another attack of the deadly virus.
As per Kwok-Yung Yuen and colleagues, SARS-CoV-2 may persist in humans, which reminds us of the coronaviruses that cause the common cold, and may continue to circulate ‘even if patients have acquired immunity via natural infection or via vaccination’. Scientists have not fully understood whether these cases reflect lingering traces of the virus, a re-eruption of an infection, or a new infection.
As per Corey Smith, head of translational and human immunology at the QIMR Berghofer Medical Research Institute in Brisbane, it may be difficult to find COVID-19 survivors, who have been reinfected, if they don’t show any symptoms. It is likely that, although the virus has managed to establish infection, his memory immune response has likely prevented any symptomatic disease in the second infection. This does suggest that natural infection may provide protection against disease, but not reinfection.
Is Re-infected Person Still Infectious?
Yes, of course. Now, the question is, how long after the initial infection might that occur? According to Thomas File, President of the Infectious Diseases Society of America and chair of infectious diseases at Summa Health, a hospital system in Akron, Ohio, the protection from reinfection varies from person to person, depending on their immune system, whether the patient developed symptoms to the first infection, and the nature of the second virus to which they have been exposed. If you look at the seasonal endemic coronaviruses, the amount of immunity can be as low as four, five, or six months to maybe up to a year or two.
International Scenario
According to Maria Van Kerkhove, the World Health Organization’s technical lead on Covid-19, more than ‘24 million people are known to have been infected with Covid-19, most of whom, including those who have a mild case, mount an immune response to the infection.’ Therefore, cases, like the one described in Hong Kong, should be properly documented, but we should ‘not jump to any conclusions.’ To better understand the quality and durability of recovered patients’ neutralising antibody response to SARS-CoV-2, more ‘studies are needed to track larger numbers of cases over time.
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