Immunity to reinfection from human coronaviruses may last only last six months, according to a study from the University of Amsterdam. It casts doubt over the practicality of introducing “immunity passports”, which some governments want to issue to COVID-19 survivors on the assumption they can’t be reinfected and are free to help the economy get back on its feet.
The study monitored 10 men over 35 years to determine antibody levels following infection for any of the four seasonal human coronaviruses. These men, then aged 27 to 40-year old, were tested at either three or six months intervals. Researchers found that there was an “alarmingly short duration of protective immunity to coronaviruses” with scientists noting “frequent reinfections at 12 months post-infection and substantial reduction in antibody levels as soon as 6 months post-infection”.
They stressed that the four strains of human coronaviruses are “biologically dissimilar” and “have little in common, apart from causing the common cold”. “Still, they all seem to induce a short-lasting immunity with rapid loss of antibodies. This may well be a general denominator for human coronaviruses. “If SARS-CoV-2 will behave like a seasonal coronavirus in the future, a similar pattern may be expected,” they went on.
They thus cast aspersions on the idea, floated by some governments, to introduce so-called “immunity passports” to people who contracted and recovered from the deadly COVID-19 virus that would allow them to travel and relax some social distancing measures.”As protective immunity may be lost by 6 months post-infection, the prospect of reaching functional herd immunity by natural infection seems very unlikely,” they warned.
Source: Euro News
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