Second bout of Covid ‘90pc less likely’ to lead to a hospital ward

PATIENTS who have had a Covid reinfection are 90 per cent less likely to end up in hospital than the first time they caught the virus, research shows.

Scientists said the findings, from a study of 350,000 Covid cases, suggest that the impact becomes more like that of “the common cold” once immunity has built up.

The research published in the New England Journal of Medicine found that those who had been infected with the virus had 90 per cent lower odds of hospital admission or death, compared with the risks from a first infection.

Scientists said the findings suggest that the virus becomes more benign as it becomes endemic, although the study took place before the emergence of the delta variant.

The study took place in Qatar, where 40 per cent of the population had detectable antibodies for the coronavirus after the first wave in March 2020.

The study looked at a national cohort of more than 350,000 unvaccinated people with infection between February 2020 and April 2021, including 1,300 who became re-infected.

Scientists then compared a sample from the first group with those who

caught the virus twice. In total, 193 people out of 6,095 with “primary” infections suffered severe disease, including 28 cases which were critical, and seven which were fatal.

Just 1,300 people became reinfected. Of those, four (0.3 per cent) presented symptoms that required hospital care, while none died or ended up in a critical condition.

Dr Laith Abu Raddad, of Weill Cornell

Medicine in Qatar, said: “It needs to be determined whether such protection against severe disease at reinfection lasts for a longer [period], analogous to the immunity that develops against other seasonal ‘common cold’ coronaviruses, which elicit shortterm immunity against mild reinfection but longer-term immunity against more severe illness with reinfection.

“If this were the case with SARSCOV-2, the virus [or at least the variants studied to date] could adopt a more benign pattern of infection when it becomes endemic”

Household mixing rose rapidly after it was announced that the four groups most at risk from Covid had received jabs. Leeds University found that in early February mixing was about 30 per cent below pre-pandemic levels, but within weeks it had risen to about 10 per cent above the normal level. Although the country was still in lockdown, the figures suggest that households began to change their habits once they believed the country was safer.