Starting Friday, eligible residents of Los Angeles County can receive a third dose of the Pfizer-BioNTech COVID-19 vaccine.
Questions remain about the rollout of COVID-19 boosters outside L.A. County.
Here’s what we know so far.
Who is eligible for a booster shot?
Under new federal guidelines, boosters will be available to four groups of people fully vaccinated with the Pfizer vaccine:
Those who are 65 and older
Those living in a long-term care facility
Those 18 to 64 who are at high risk of severe COVID-19
Those 18 to 64 who are frequently exposed to COVID-19 because of work or other obligations
A key CDC advisory committee did not support boosters for people in the fourth category, but CDC Director Dr. Rochelle Walensky overruled it, siding with the FDA in favor of boosters for nurses, teachers and others with high occupational risk.
To be eligible, people also must have received their second Pfizer shot at least six months before seeking the booster. The CDC recommends receiving a booster within eight months of the second dose.
Do I need a booster shot?
Although the vaccines have been available for only a matter of months, studies show that their effectiveness can dip over time — a phenomenon known as waning immunity. The vaccines are still providing protection against severe illness, hospitalization and death, the CDC says, but "with the Delta variant, public health experts are starting to see reduced protection against mild and moderate disease."
Nevertheless, the CDC isn't yet recommending the booster shot for everyone in the eligible groups. Instead, the agency says that the people who should receive the booster are those who are at last 65 years old, who live in a long-term care facility, or who are 50 to 64 years old with underlying medical conditions. It adds that others in the eligible groups need to consider their individual benefits and risks when deciding whether to obtain a third shot.
In addition to the groups eligible for Pfizer boosters, the CDC recommends that people with moderately to severely compromised immune systems get a third dose of the Pfizer or Moderna vaccine 28 days after their second shot to help build more resistance.
Can you mix and match vaccines?
If you received the Johnson & Johnson vaccine, you are ineligible for a booster shot, according to the CDC. Because the vaccination mechanics of Johnson & Johnson's shot are different from Pfizer's and Moderna's, the CDC says, more research needs to be done before deciding whether it's safe and effective to mix the two types.
The Los Angeles County Department of Public Health also advises against mixing and matching Pfizer and Moderna, pending more research and guidance from the FDA.
When and where can you get your booster?
L.A. County residents can start getting their shots Friday at whatever facility gave them their previous doses. You can make an appointment or find a site that provides shots on demand at the county Public Health Department's website. Pharmacies and community clinics already have doses on hand.
Proof of prior Pfizer vaccination must be provided at the time of your third dose, either digitally or with your vaccination card.
This story originally appeared in Los Angeles Times.