A PAST coronavirus infection does not protect young people against reinfection, a new study has found.
Boffins have found that even with antibodies from a previous Covid-19 infection, getting a vaccine is still the number one way to prevent getting coronavirus again and cut rates of transmission.
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Researchers studying more than 3,000 healthy members of the ultra-fit US Marine Corps, most aged 18-20, found around ten per cent who had previously had Covid got it again.
That compared to around half of those picking up the virus for the first time between May and December last year.
Although the study was in young, fit, mostly male recruits, the researchers believe the risk of reinfection applies equally to many young people.
Professor Stuart Sealfon, of Icahn School of Medicine at Mount Sinai, New York, and senior author of the study, said: “As vaccine rollouts continue to gain momentum it is important to remember that, despite a prior Covid-19 infection, young people can catch the virus again and may still transmit it to others.
“Immunity is not guaranteed by past infection, and vaccinations that provide additional protection are still needed for those who have had Covid-19.”
The researchers pointed out the exact rates of reinfection would vary from the study, because crowded living conditions on a military base and close contact required for basic training likely contribute to a higher overall infection rate.
Comparing the new infections between patients who had Covid for the first time and those who were reinfected, the professors found the amount of measurable virus – or viral load – differed.
In reinfected marines, the viral load was on average only 10 times lower than in those infected for the first time.
The authors believe this suggests some reinfected people could still be able to transmit the virus.
The study published in The Lancet Respiratory Medicine journal also showed most new cases – 84 per cent of those infected with Covid in the past – were asymptomatic while 68 per cent of those having coronavirus for the first time had no symptoms.
