Editor’s note: This story was produced in conjunction with the Latino Communities Reporting Lab. A free Spanish translation is available at Myrecordjournal.com/latino-news.
As walk-in appointments become more available at many locations statewide, people may no longer get their second vaccine dose at the same place as the first.
But they do need to make sure they get the same brand and understand when to get that second shot, health officials said.
Proper spacing between COVID-19 vaccine doses is critical for achieving the maximum protection against the virus, health care experts said. The Pfizer-BioNTech vaccine requires a second dose after three weeks and the Moderna vaccine requires four weeks.
“It’s not arbitrary at all,” said Dr. Henry Anyimadu, Hartford HealthCare infectious disease specialist. “The first dose is a primer dose, it recruits the antibodies, recruits the T-cells. The first dose primes the immune system and gets it ready.”
There is some flexibility, Anyimadu said. Second doses of both vaccines can be as early as four days before the three- or four-week marker, and as late as six weeks from the first dose.
“This leaves room for some contingency,” Anyimadu said. “There is some protection several weeks after the first dose, and two weeks after second dose.”
Vaccine research in primates showed that it takes three weeks for the body to build up immune cells. That’s the reason there is a wait between first and second doses.
Vaccine makers and health experts say the COVID-19 vaccines can offer 91.3 percent protection from seven days to six months after the second dose but what is unclear is when or if, we might see the need for boosters.
Moderna Chief Executive Officer Stéphane Bancel recently said that people who received the Moderna vaccine will “likely” need a third dose after 6 to 12 months, according to CBS News. Bancel said the booster will be available in the U.S. by fall and will be a combination shot meant to protect against COVID-19 and seasonal influenza.
Pfizer executives have said the same thing leading many to argue there is going to be a cycle of vaccines and boosters, but doctors liken it to flu shots and other vaccines that require boosters at various intervals.
Booster shots work like a wake-up call for the immune system, doctors said. Vaccines stimulate the body to create antibodies that are capable of recognizing the coronavirus and, if someone encounters it, killing it and any cells that have been infected by it, often before any symptoms appear, according to Healio, an online news site for health care professionals.
Memory T and B immune cells guard the body in case another encounter occurs. But over time, the numbers of these memory cells diminish and the immune system may forget how to recognize the virus.
Booster shots are a reminder to the immune system of how to recognize the germ causing the disease, according to Healio.
Albert Bourla, the chief executive at Pfizer, recently said: “There will be likely a need for a third dose somewhere between six and 12 months (following the first two doses) and then from there, there will be an annual revaccination.”
But National Institute of Allergy and Infectious Diseases Director Dr. Anthony S. Fauci recently said public health — and not pharmaceutical companies — will determine the need for a booster dose of COVID-19 vaccine.
Fauci explained in an April 18th “Meet the Press” interview that researchers will be able to measure antibody levels and predict when protection is so low that breakthrough infections are likely.
“When that happens, clearly, you’re going to see a recommendation for a booster,” Fauci said.