People reinfected with coronavirus had 90% lower chances of hospitalisation or death than an initial infection, according to a new study. Research published in the New England Journal of Medicine found that there were few confirmed reinfections among 353,326 people who got COVID-19 in Qatar, where about 40% of the population was detected with antibodies against COVID-19 by the end of the first wave of infections between March and June of 2020, before two more waves from January through May of 2021.
To determine how many people got reinfected, scientists from Weill Cornell Medicine-Qatar compared the records of people with PCR-confirmed infections between February of 2020 and April 2021. They excluded 87,547 people who got the vaccine.
Researchers found there were 1,304 reinfections among the remaining cases with the median time between the first illness and reinfection being about 9 months.
Among those with reinfections, only four ended up in the hospital, and none in the intensive care unit. Among the initial cases, 28 were considered critical. There were no deaths among the reinfected group, while there were seven deaths in the initial infections.
“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 short-term immunity against mild reinfection but longer-term immunity against more severe illness with reinfection,” the study said.
“If this were the case with SARS-CoV-2, the virus (or at least the variants studied to date) could adopt a more benign pattern of infection when it becomes endemic.”
Another study done in Denmark and published in March found that most people who had COVID-19 seemed to have protection from reinfection that remained stable for more than six months, but a check of the demographics of who was getting infected again showed it was mostly people 65 and older.