Millions of people who have recently developed Covid-19 may have some new questions about their immunity. If they have not yet received a booster shot, do they still need to get one? And when is the optimal time to get it?
Federal health officials continue to recommend that everyone get vaccinated and boosted, regardless of whether they have had Covid-19. But more than half of fully vaccinated Americans who are eligible for booster shots have not yet received them. And the guidance on when to schedule a booster appointment after recovering from Covid-19 is less than clear. Here is what we know.
What is the point of getting a booster after you have had Covid-19?
Most experts agree that vaccines can offer a more reliable and effective immune boost than a natural infection can.
When you get infected with the coronavirus, your immune system mounts a series of responses that bulk up the body’s defences against future infections. One of the best ways scientists know how to measure that response is to look at how many antibodies you have produced.
In general, people who have been infected with the coronavirus tend to have lower levels of antibodies than those who have been vaccinated, said Aubree Gordon, a public health researcher at the University of Michigan.
One of the reasons for this difference is that infections trigger many parts of the immune system and the size of the antibody response will depend on factors like how much virus you inhaled, whether you have underlying medical conditions and the severity of your symptoms. “You may have a high level if you were sicker or sick for longer,” Gordon said. “But it’s still going to be lower than what we see with the vaccine.”
Vaccines provide a tailored set of instructions for the immune system to use in the absence of any distractions, such as an active infection, said Paul Thomas, an immunologist at St Jude Children’s Research Hospital in Memphis, Tennessee. And most people who get vaccinated develop a strong and predictable antibody response. A booster shot reminds the body to bump up its defences — even faster than the first or second shot — in a matter of days.
Studies also suggest that the antibodies produced after vaccination tend to remain at protective levels for longer.
“I think that’s the biggest argument to get boosted, frankly, even if you’ve had a recent infection,” said Dr Amy Sherman, an infectious disease physician at Brigham and Women’s Hospital in Boston. “It’s a surefire way to give further protection and make sure your immune system produces peak responses.”
When is the best time to get a booster?
There is no hard and fast rule for when to schedule a booster shot after having Covid-19. The optimal timing will depend on your individual circumstances, including how severe your illness was, how long it has been since your symptoms resolved and what your risk for re-exposure is.
But if you are dealing with an active infection, the Centres for Disease Control and Prevention recommends waiting at least until you no longer have symptoms and have met their criteria for ending isolation.
Some scientists recommend deferring your booster longer. Ali Ellebedy, an immunologist at the Washington University School of Medicine in St Louis, said it might make sense to wait until you have fully recovered or can get a negative PCR test, although this isn’t a CDC requirement to end isolation and may not occur until a few weeks — or even months — later.
“You just don’t want to overwhelm your system,” Ellebedy said. Let your immune system rest after fighting off the coronavirus and before asking it to ramp up again with the vaccine. This will also allow for a more refined and durable response, he said.
Of course, deferring a booster isn’t the right option for everyone. If you have a high risk of reinfection or serious illness — whether because of your age, medical conditions or a weakened immune system, or because you live or work in a setting that increases your likelihood of exposure — then you may want to boost your immunity with an extra vaccine dose sooner rather than later, Ellebedy added.
—The New York Times
