If you are under the age of 65 and have had COVID-19 then most likely you are protected from catching it twice, at least for six months after the infection.
But those aged 65 years and older are at higher risk of getting the disease again.
According to a new study, the protection against repeat infection among adults 65 years and older is 47 percent while for younger people it is 80 percent.
The study also found that immunity and protection will last at least six months after infection.
Dr Daniela Michlmayr, the study’s co-author, said:
“In our study, we did not identify anything to indicate that protection against reinfection declines within six months of having COVID-19.
The closely related coronaviruses SARS and MERS have both been shown to confer immune protection against reinfection lasting up to three years, but ongoing analysis of COVID-19 is needed to understand its long-term effects on patients’ chances of becoming infected again.”
The study analysed COVID test data on 4 million people in Denmark from March to December 2020.
It shows that most people who recovered from COVID infection were protected against reinfection, only 0.65 percent returned positive tests, meaning about 1 in 200 people tested positive for COVID twice.
Seniors are more susceptible to coronavirus reinfection as generally aging is a key factor in the severity of the disease.
Dr Steen Ethelberg, study co-author, said:
“Our study confirms what a number of others appeared to suggest: reinfection with COVID-19 is rare in younger, healthy people, but the elderly are at greater risk of catching it again.
Since older people are also more likely to experience severe disease symptoms, and sadly die, our findings make clear how important it is to implement policies to protect the elderly during the pandemic.
Given what is at stake, the results emphasise how important it is that people adhere to measures implemented to keep themselves and others safe, even if they have already had COVID-19.
Our insights could also inform policies focused on wider vaccination strategies and the easing of lockdown restrictions.”
Due to the limitation of clinical information it is not clear yet if the severity of COVID symptoms influences patients’ protection from catching it again.
The study was published in The Lancet (Hansen et al., 2021).