COVID Antibodies Could Last Longer Than We Thought, According to New Study
The only upside of dealing with COVID-19 is the reassurance that you likely won’t have to experience the virus again soon. But just how long COVID antibodies last has been a matter of debate for some time.
“We don’t know, exactly,” says William Schaffner, M.D., infectious disease specialist and professor of medicine at the Vanderbilt University School of Medicine in Nashville. “Part of that is because COVID has complicated things for us by coming up with new variants that are a little different from the previous variants that are out there.”
Thomas Russo, M.D., a professor and chief of infectious diseases at the University at Buffalo in New York, agrees. “Our data are somewhat imperfect,” he says. “The studies come out and the variants are staying ahead of our clinical data to a degree.”
However, a recent large study published in The Lancet suggests that you may get longer protection from being infected with COVID-19 than experts previously thought. What may happen from person to person, though, is a little complicated. Here’s what you need to know about how long COVID immunity lasts, and why doctors still recommend you get a booster shot if you’ve had the virus.
How long does natural immunity after COVID-19 last?
Again, it can be tough to say for sure how long your natural immunity will last after you have COVID-19 given that the variants keep changing and everyone’s immune system is different. However, there is some data to suggest you can expect protection for a certain amount of time.
In general, natural immunity after COVID-19 seems to last for at least six months after you’ve been infected, per the Centers for Disease Control and Prevention (CDC).
A new study published in The Lancet found that the immunity you get from being infected by COVID-19 is as protective as vaccination when it comes to severe disease and death. The study, which is the largest meta-analysis to date on immunity after having COVID-19, analyzed data from 65 studies from 19 countries and compared the risk of getting the virus again in people who had just recovered from it to those who hadn’t been infected. (Worth noting: Newer Omicron subvariants like BQ.1 and the currently circulating subvariants weren’t in the study.)
The researchers found that having COVID-19 lowered the risk that someone would be hospitalized and die from a COVID reinfection by 88% for at least 10 months.
However, people could still be reinfected with the virus (especially an Omicron subvariant) which indicated that, while protection against hospitalization and death stayed high for the study period, protection against having symptoms of the virus fades faster.
Having had COVID-19 before the Omicron variants emerged didn’t seem to help much. People who had previous infection with a different variant were 74% likely to be protected from reinfection after a month, but that dipped to 36% by 10 months.
How long does vaccine-induced immunity last?
It’s not entirely clear. The CDC is a bit vague on this one, saying online that it’s still being studied. However, data published in The New England Journal of Medicine says that you can expect at least six months of protection after being vaccinated, and that’s generally what doctors advise patients as well.
“It’s going to vary by who you are and how strong your immune system is—the same considerations apply as with prior infection,” Dr. Schaffner says. However, he says, there is some data that suggest that people who are older or have compromised immune systems will have waning immunity after four to six months. “That doesn’t mean it drops to zero, though,” he says.
Dr. Schaffner also stresses this: “The data indicates that people who are up to date with their vaccines have a much lower risk of hospitalization than people who are partially vaccinated or unvaccinated. If you’re totally unvaccinated, your risk of hospitalization is about 12 to 15 times greater than people who are vaccinated.”
Worth noting: The recent Lancet study found that vaccination generally provided the same level of protection against reinfection as a previous infection. However, it only looked at people who had two doses of the mRNA vaccine—not three, four, or the bivalent booster.
Do any COVID-19 subvariants evade immunity?
As of now, no. However, the most recently circulating variants do seem to be fairly good at evading immunity. “XBB.1.5 is extraordinarily immuno-evasive,” Dr. Russo says. In fact, the World Health Organization (WHO) calls the XBB variants " the most antibody-resistant variants to date."
Still, “all the variants are subject to some protection from the vaccines at the present time,” Dr. Schaffner says.
Why booster shots are important for immunity
It’s important to note that this is a “controversial topic," even among infectious disease doctors, says Liam Sullivan, D.O., an infectious disease physician at Corewell Health. Some think that a bivalent booster shot isn’t necessary for people under the age of 50 who are in good health, he points out, noting that the evidence is “limited” that a booster shot will help people who are fully vaccinated and healthy. “If you're young and healthy, and had an infection in the previous 12 months, you probably don’t need it—the infection probably served as your booster shot,” he says.
But the CDC says it’s a good idea to get a booster three months after you were infected in order to get the maximum protection going forward. Research has also found that people who were infected and then vaccinated (or vice versa) have the best protection against COVID-19 in the few months afterward.
Also, immunity fades over time, and it’s better to develop it from a vaccine than infection, Dr. Russo says. “Relying on immunity from prior infection runs the risk of you dying or having long-term health consequences,” he points out.
What is hybrid immunity?
You may have heard the term “hybrid immunity” at some point. This “refers to when you’ve been vaccinated and infected—either vaccinated first and infected after, or infected first and vaccinated after,” Dr. Sullivan says.
People who have hybrid immunity “probably have the best form of immunity rather than people who have just been infected or vaccinated,” Dr. Sullivan says. But, he adds, “I wouldn’t encourage people to go out and try to get infected.”
Dr. Russo agrees. “If you’ve been infected and you want to optimize your protection and minimize the chances of having a bad outcome, getting the bivalent booster is your best strategy at this time,” he says.
Overall, Dr. Sullivan recommends that people keep in mind that there is a lot of research still ongoing with COVID-19. “There is still a lot to be figured out and there is a lot of gray,” he says. “It’s going to take a lot of study and time until we have more information. People shouldn’t be shocked if this information changes.”
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