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If you recovered from a COVID-19 infection, probably the last thing you want is to get the virus again. And, until recently, you may have thought or expected that, after contracting the disease, you would be protected – as if you could, say, against chicken pox.
But scientists have known for a long time that immune protection may be shorter with some viruses than with others. And reports of people being reinfected with the coronavirus, along with the emergence of several variants that appear to be more contagious and dangerous, have raised concerns that, for some people, a single COVID-19 attack may not be the last.
For people who took COVID-19 last year, “the question will be, ‘Will they still have immunity and will that immunity work against variant strains?’ ”Says Aaron Glatt, MD, chairman of the medical department and head of infectious diseases at Mount Sinai South Nassau in Hewlett, NY
One year after the start of the pandemic, the Centers for Disease Control and Prevention say that reinfections are rare, but possible.
Here’s what you need to know about reinfection, including how to prevent a second COVID-19 infection.
Re-infections are uncommon, but variants can make them more likely
In the early months of the pandemic, reinfections seemed unusual, although researchers have documented some cases. One of the first confirmed cases in the U.S. was a 25-year-old Nevada man who tested positive for the virus in April 2020 and again in June, according to an article in The Lancet. And last October, five residents of a specialty ward in Kentucky appeared to have been infected again after they contracted the virus in a July outbreak there.
But the increase in variants is causing experts to fear that reinfections may become a major concern.
The most alarming evidence of this comes from Brazil, mainly from the city of Manaus. The research suggested that more than 70 percent of the population of Manaus had been infected with SARS-CoV-2, the virus that causes COVID-19, in the fall of 2020. That was enough to provide protection for the community or immunity from herd, according to Peter Katona, MD, an infectious disease specialist at UCLA’s David Geffen School of Medicine in Los Angeles. Still, in December, infections in the city increased, supposedly overburdening the health care system.
This attack was probably caused by a variant of SARS-CoV-2 known as P.1. It can prevent some of the antibody responses induced by previous infection and potentially reduce the vaccine’s effectiveness, according to virologist Andrew Pekosz, PhD, professor and vice president of the molecular microbiology and immunology department at the Johns Hopkins Bloomberg School of Public Health in Baltimore, who spoke at a Johns Hopkins briefing on viral variants in February.
This increase in reinfection and serious illness in an area where it was thought that there was enough infection to obtain herd immunity is “a nightmare scenario,” says Katona.
In addition to P.1, there are at least two other variants of concern spreading in countries around the globe: B.1.1.7, first discovered in England, and B.1.351, found for the first time in South Africa. All three infected people in the United States. And these variants may be more transmissible, more likely to cause serious illness or better evade antibodies generated by vaccination or a previous infection. Some have a combination of these characteristics. Other variants were found recently in the USA
And as long as the virus continues to spread rapidly around the world, reinfection will remain a possibility. That’s because the more people are infected, the more opportunities the virus has to catch new mutations that can make many people sick again. “Controlling the case numbers will be the most critical thing we will do to decrease the likelihood of emerging variants in the population,” said Pekosz.
Older people with compromised immune systems may be at higher risk
Although a previous infection, whether with the original virus or a variant, almost certainly provides some protection, reinfection is possible. And some people may be more vulnerable than others.
This includes older people. A new study in The Lancet found that people under the age of 65 who already had COVID-19 had about 80 percent immunity against reinfection. In contrast, for those 65 and older, protection dropped to 47 percent. This may be because immune function tends to decline with age.
Other people with a weakened immune system also face an increased risk of reinfection, says Katona. This includes cancer patients or people who have received an organ transplant.
Masks and social distance can help prevent reinfection
As with infection, the risk of reinfection increases the more viral particles you are exposed to. That is why experts recommend that people who have had the disease continue to take precautions to limit their exposure.
“Even if you had COVID, you are not Superman,” says Glatt. “You can’t walk around saying that you are safe.”
Because of this, the researchers say that after recovering from COVID-19, you should continue to wear a mask when in public, keep your distance from others, wash your hands and try to limit interactions to well-ventilated spaces or outdoors. .
There is another reason to take these precautions after you have the disease: you may have been infected again and you can spread the disease, but you have no symptoms. And COVID-19 can be transmitted by asymptomatic people.
Approximately one in six people with COVID infections are asymptomatic, according to an estimate by Australian researchers. And asymptomatic reinfections can be underestimated because there is little screening for people without symptoms, said Akiko Iwasaki, PhD, professor of immunobiology at Yale School of Medicine, in a commentary on the importance of reinfections at The Lancet.
Being vaccinated can help prevent reinfection
Even if you have already taken COVID-19, you should consider vaccination as soon as you are eligible – especially if you are 65 or older. Early evidence suggests that vaccine protection is stronger and longer lasting than that obtained with a previous infection. In addition, the vaccines used in this country still appear to be effective against P.1 and other known variants.
Still, either because immunity decreases over time or because some variants may avoid the protection provided by a vaccine, it is possible that people will eventually need reinforcements against new variants.
And just as people who have had the disease must wear a mask and follow practices of social detachment when they are in public, so should people who have been vaccinated.
Read more about what you can and cannot do after being vaccinated.