The possibility of coronavirus reinfection is a concern since the first reports of people falling ill in 2020 surfaced – while many around the world were still in isolation. But so far there is relatively little data on how widespread this phenomenon is.
The first large-scale study to address that question was published this week in The Lancet, and it found that the vast majority of indeed, people who have had COVID-19 are protected from getting it again – for at least six months. However, people 65 and older are much more likely than younger people to experience a recurrent infection.
The researchers analyzed data from Denmark’s national COVID-19 testing program, which has offered free PCR testing to about 4 million people living in the country. Overall, they found that a very small percentage of the population – 0.65% – experienced reinfection.
For people over 65, getting the coronavirus once offered about 80% protection against re-infection. But for people 65 and older, it only offered about 47% protection against getting COVID-19 again, further highlighting how dangerous this disease can be for older adults.
“As older people are also more likely to have serious disease symptoms and, unfortunately, die, our findings highlight the importance of implementing policies to protect the elderly during the pandemic,” said Steen Ethelberg, author of the Statens Serum Institut study. . in Denmark, it said in a statement. “Given what is at stake, the results highlight the importance of people adhering to measures implemented to protect themselves and others, even if they have already had COVID-19.”
“Given what is at stake, the results highlight the importance of people adhering to measures implemented to protect themselves and others.”
– Steen Ethelberg, researcher at Statens Serum Institut in Denmark
What this study means for us (and the future of the pandemic)
Overall, this news is positive, but it also highlights the need for constant vigilance. Many factors can still play a role in getting sick.
The emergence of different variants is one of them. Coronavirus reinfection has become a particular concern in recent months as new variants have started circulating around the world.
A vaccine study in South Africa – where a variant is circulating that experts fear is more contagious and may make current vaccines less effective – found new infections in 2% of people who were previously infected with another variant of the coronavirus.
The large new study from Denmark did not investigate the role of variants in reinfection, given the time frame of the study. So it offers no clues as to whether variants make it more likely that someone will come across COVID-19 more than once.
Previous case studies of people reinfected were troubling because they suggested it was possible to get sicker the second time around. This was the case with an otherwise healthy 25-year-old man in Nevada who tested positive for COVID-19 last spring, recovered and then became ill again. He had to be hospitalized for the second time. But even as those initial reports surfaced and drew a lot of coverage, researchers were careful to point out that that outcome is rare.
Since the new re-infection research has not been conducted in the United States, it is unclear whether the findings apply here in the same way. But overall, researchers are optimistic that most people who get COVID-19 won’t experience reinfection soon after. And they continue to study immunity, both after infection and after vaccination. It is unclear at this point how long immunity lasts after a person receives a COVID-19 vaccine.
All of this underscores the continued need for basic preventive measures, even as the number of coronavirus cases begins to decline nationwide.
The Centers for Disease Control and Prevention recommends that people who have had COVID-19 get vaccinated as soon as it becomes available to them, largely because they are unlikely to become reinfected if they come into contact with the virus.
Continuous wearing of a mask is also essential, as qUestions remain about the extent to which those who have recovered from COVID-19 can spread it to others if they are exposed again. In addition, wearing a mask helps reduce the chance that a person will get the virus more than once.
Earlier this month, the CDC released new guidelines stating that fully vaccinated Americans can gather safely indoors without wearing masks or social distancing, providing a promising glimpse of how restrictions are likely to ease as more shots go into more arms. But for now, it’s a race against time to ensure that millions of Americans are immunized while variants continue to spread.
Experts are still learning about COVID-19. The information in this story is what was known or available at the time of publication, but the guidelines may change as scientists discover more about the virus. Consult the Centers for Disease Control and Prevention for the most recent recommendations.