Since the COVID vaccine started to be administered at the end of December, we've all been told that following the recommended timeline between first and second doses is key to getting the full 95-percent protection against the virus. But with the vaccine rollout happening amid winter storms that have caused delays in vaccine shipments and temporary shutdowns of vaccination sites, that's not always possible. If you're worried about not being able to get the second shot of your COVID vaccine exactly 21 days after your first Pfizer dose or 28 days after your first Moderna dose, the Centers for Disease Control and Prevention (CDC) has some new advice you need to follow. "You should not get the second dose earlier than the recommended interval," the agency advises. Read on to find out what you should do and shouldn't do if you can't stick to the recommended vaccine timeline, and for more guidance on getting your shots, know that The CDC Says Don't Do This Within 2 Weeks of Your COVID Vaccine.
The CDC says you have a "grace period" if you absolutely must get your second dose early.
In its guidance for clinicians administering the vaccine, the CDC clearly says: "Persons should not be scheduled to receive the second dose earlier than recommended (i.e., 3 weeks [Pfizer-BioNTech] or 1 month [Moderna])." However, if you're in a situation where you absolutely must get your second shot early, the agency says you have a grace period of a few days. "Second doses administered within a grace period of 4 days earlier than the recommended date for the second dose are still considered valid," the CDC guidance reads.
However, if for some reason you do get your second shot even earlier than that (before 17 days for Pfizer or 24 for Moderna), that doesn't mean you need to restart the process. "Doses inadvertently administered earlier than the grace period should not be repeated," the CDC says. And for more on what's not OK to do post-shot, Don't Do This Until a Month After Your COVID Vaccine, Experts Warn.
Later may be better than earlier when it comes to your second dose.
Of course, "better late than never" applies to the second dose of COVID vaccines, too; but so does "better later than earlier," according to the CDC and other medical experts. Diane Griffin, MD, a virologist at the Johns Hopkins Bloomberg School of Public Health, told the Los Angeles Times that she "personally would choose a few days late over early."
"Your immune response will work perfectly well if you take more time,” William Schaffner, MD, medical director of the National Foundation for Infectious Diseases, told the AARP. “But if you do it too early, the second dose may not invoke an optimal response.”
At Walgreens, where Rina Shah is group vice president of pharmacy operations and services, "patients can receive the second dose as long as it follows the immunization window"—the key word being "follows," as Shah told NBC News. "We encourage patients to schedule the second dose appointment as close to the earliest appropriate date, but a bit after is OK," Shah said. And if you want to get your shot at your local Walgreens pharmacy, check out If You Live in These States, You Can Now Get Vaccinated at Walgreens.
The CDC says you can wait up to six weeks to get your second shot if necessary.
According to the CDC, "If it is not feasible to adhere to the recommended interval and a delay in vaccination is unavoidable, the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines may be administered up to 6 weeks (42 days) after the first dose."
The CDC says there is limited data on the efficacy of Pfizer and Moderna vaccines administered beyond a six-week window. However, once again, the agency warns that "if the second dose is administered beyond these intervals, there is no need to restart the series." And for more COVID news delivered right to your inbox, sign up for our daily newsletter.
But even if it's later than six weeks, there's no harm in getting that second shot.
"You should get your second shot as close to the recommended 3-week or 1-month interval as possible," the CDC says. "However, there is no maximum interval between the first and second doses for either vaccine." Meaning, even if it's longer than six weeks, you should still get that second shot.
Buddy Creech, MD, the director of the Vanderbilt Vaccine Research Program at Vanderbilt University Medical Center in Nashville, Tennessee, has overseen clinical trials for the Moderna vaccine. According to what he's seen, the vaccine should work even if your second dose is delayed more than what is recommended by the CDC. Creech told NBC News that people should "not panic" if they have to stretch the 21-day or 28-day interval between doses. "Even if it's four weeks, six weeks, eight weeks before you can get that second dose, it's fine from an immune system standpoint," Creech said.
Thomas Denny, chief operating officer of the Duke Human Vaccine Institute, told Scientific American that it all comes down to the length of clinical trials, which were shorter in order to get the vaccine approved and administered to the public as quickly as possible. "You could have done dosing studies for two years, but that would not be the most responsible thing to do in a world like this,” Denny said. “Don’t let the perfect be the enemy of the good.” And for more on what to expect from your vaccination, find out why The CDC Says These 3 Side Effects Mean Your Vaccine Is Working.