Study: COVID-19 reinfection rare but more common in older people

IDLE TIME Two elderly residents of Manila’s Pandacan district sit out the four-day lockdown imposed on their neighborhood amid a spike in COVID-19 cases. —LYN RILLON

LONDON—The majority of people who have had COVID-19 are protected from getting it again for at least six months, a study published on Wednesday showed, but older people are more prone to reinfection than younger people.

The study, appearing in the Lancet medical journal, found that just 0.65 percent of patients tested positive a second time for the coronavirus after previously being infected during Denmark’s first and second waves. That was much lower than the 3.27 percent who were positive for the virus using highly accurate PCR tests after initially being negative.

Greater risk

But the study found that people over the age of 65 had only 47 percent protection against repeat infection, compared to 80 percent protection for younger people.

“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,” said Steen Ethelberg of Denmark’s Statens Serum Institut.

No evidence

“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,” Ethelberg said.

The authors of the study found no evidence that protection against reinfection declined over a six month follow-up period, but said further studies were needed to assess protection against reinfection from variants of the coronavirus.

The data analyzed was collected through Denmark’s national testing strategy, under which 69 percent of the population, or 4 million people, were tested over the course of 2020.