The news that coronavirus immunity may only last a few months will come to a blow to the millions of people who have had Covid-19 and assumed they will never fall ill with it again.
Researchers at King’s College London looked into the immune response of 90 patients and healthcare workers at Guy’s and St Thomas’ NHS Trust and found antibodies peaked three weeks after the onset of coronavirus symptoms before declining.
It is the first comprehensive study of the longevity of antibody responses in both symptomatic and asymptomatic individuals infected with Covid-19. The results clearly demonstrate that in the majority of infected individuals antibody responses, a major form of defence against microbes, decline 60 days after the onset of symptoms.
There is some good news, however, as previous studies on other coronaviruses suggest that re-infection is associated with less severe disease or no disease at all. In both Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS) infection, neutralising antibodies have been shown to wane over time. But even two years after becoming infected the majority of individuals still maintain some, albeit, low level of antibodies.
‘Warning shot’
Experts have said the study serves a warning shot to those who have been found to have antibodies to Covid-19 yet have only had mild, if any symptoms.
“In the same way that these patients were surprised to have antibodies to Covid-19, we should not be surprised if any protective benefit is mild, or at least transient,” he said. “Even those with a positive antibody test, especially those who cannot account for where they may have been exposed, should continue with to use caution, social distancing and appropriate mask use.”
Whether Covid-19 immunity only lasts for such a short time is of course unknown. Further studies with more recovered patients and asymptomatic individuals followed over longer time periods will be needed to answer that question.
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Source: INEWS
