4 min read.Updated: 21 Nov 2021, 06:34 PM ISTSUMATHI REDDY, The Wall Street Journal
With Thanksgiving gatherings and travel ahead for many, here are science-backed answers for when to time the shot for optimal protection
As eligibility for Covid-19 boosters widens in parts of the U.S., some people wonder when they should time their shots to maximize protection.
Doctors say that in most cases, the best time to get a booster is as soon as you are eligible. Protection from a booster shot will bolster your immune defenses as the holidays approach and Covid-19 cases rise in parts of the country. Even if your antibody levels decline somewhat over time, your protection remains stronger after a booster.
About 15% of all U.S. adults have gotten Covid-19 boosters, according to the Centers for Disease Control and Prevention. The agency has said that people who were initially vaccinated with a Pfizer–BioNTech or Moderna vaccine can get a booster as soon as six months after their second dose. Any adult who got a Johnson & Johnson vaccine may get a booster at least two months after the single-dose shot. The CDC has backed mixing and matching vaccines for boosters, too.
So how to decide what the best timing is for your booster? Here’s what scientists and doctors advise.
The holidays are coming up. If I get a booster now, will I be better protected?
For people who initially received Pfizer and Moderna vaccinations, the body undergoes a similar process after a booster shot as it does following the second dose of the primary series. The shot marshals memory B cells to produce neutralizing antibodies, which help cells fend off the virus that causes Covid-19.
How long will the booster’s protection last?
Antibodies from a booster shot will wane over time—but that doesn’t mean your immune protection has disappeared. Antibody levels decline with all vaccines, scientists say.
The body produces an initial burst of antibodies, peaking one or two weeks after a booster shot. Levels then decline and eventually stabilize, says John Wherry, director of the Institute for Immunology at the University of Pennsylvania.
Covid-19 vaccines haven’t been around long enough to study long-term immunity over several years, either from the initial shots or boosters. But if you look at other vaccines, antibody levels often stabilize better after a booster, says Dr. Wherry. “The slope of decay is shallower," he says.
“The question is: Does[the level of antibodies] settle at a higher level and at a more steady level than it did with the primary vaccination?" says Dr. Wherry. “That’s the hope."
Will the antibodies produced after my booster shot last longer than after my original vaccination?
There is some preliminary evidence that the levels of antibodies after a booster are higher than after a second dose of an mRNA vaccine. The finding suggests the booster could offer somewhat longer protection, says Stephanie Langel, a medical instructor in the department of surgery at Duke University School of Medicine and a viral immunologist. But higher antibody levels would still wane over time, so scientists are hoping a booster will also produce better-quality antibodies.
“Not only do we want to see an increase in the numbers, we want to know, do you get potentially better binding of the virus after the booster?" says Dr. Langel. “We can’t say that for sure."
What is the best booster timing if I am 65 and older? And what if I am over 50 with an underlying health condition?
Doctors say that people who fall into higher-risk categories should get a booster as soon as they are eligible, which is six months after their second mRNA shots, according to CDC guidelines.
What if I got Johnson & Johnson initially?
You should get a booster at least two months after your first shot, according to the CDC.
If I’m under 50 and healthy, should I get a booster as soon as I’ve passed the six-month mark? Or should I wait until I get closer to a higher-risk event?
It might make sense for healthy, non-elderly people to time a booster shot to a couple of weeks before a big event, such as an international trip or a wedding,says Deepta Bhattacharya, a professor of immunobiology at the University of Arizona College of Medicine in Tucson.
But timing depends on the circumstances of your life and community. If Covid-19 cases are low and stable in your community, and your day-to-day life doesn’t present a lot of exposure risk, waiting a couple of months may be fine. “Two doses is still doing a pretty good job of keeping you out of the hospital," he says.
Other experts advise against waiting to get a booster, especially with winter approaching and Covid-19 cases rising in some parts of the country.
The antibodies that a booster shot produces won’t be gone in a couple of months, even if their levels decline slightly, says Ali Ellebedy, an associate professor of pathology and immunology at Washington University School of Medicine in St. Louis.
What’s more, predicting the course of the virus is tough. A more contagious variant could surface and lead to more risk while you’re waiting.
This story has been published from a wire agency feed without modifications to the text