COVID-19 vaccine booster shots available to many people


Dear Doctors: My wife and I are now six months out from our second shots of the Pfizer vaccine, and we want to get boosters. Can you please explain where things stand in terms of who is eligible, and for which vaccines? Is there any benefit to a mix-and-match approach?

Dear Reader: The United States Centers for Disease Control and Prevention has now expanded eligibility for COVID-19 booster shots to include the widest group of people thus far. This action follows a unanimous recommendation by a key Food and Drug Administration committee in late October.

Eligibility for COVID-19 boosters now includes anyone over age 65. It also includes those who are 18 and older and are living with a health condition that puts them at risk of developing severe illness. This includes medical conditions such as cancer, chronic lung or heart disease, autoimmune diseases, diabetes, liver disease, obesity and pregnancy, as well as medical treatments that adversely affect the immune system. Individuals living with mood disorders, including depression and schizophrenia spectrum disorders, are now also eligible for a booster.

Those at higher risk of becoming infected due to either their living conditions or their work are also eligible for boosters if they’re over 18. This includes people who are living in group situations and long-term care settings, and those whose work puts them into contact with the public.

The CDC’s decision also allows people to receive a booster shot that is different from their original vaccination. It is recommended that recipients of the Moderna or Pfizer vaccines who elect to get a booster have it administered six months after the second dose of the initial vaccination cycle. Recipients of the Johnson & Johnson vaccine are advised to receive a booster shot at least two months after the first dose. The boosters are the same vaccine as the original, but include just one-half of a dose. When it comes to side effects, people report that they are similar to those experienced with the initial vaccine. That includes pain at the vaccination site, fatigue, muscle pain, fever, headache and chills.

Elizabeth Ko, MD and Eve Glazier, MD

Regarding your question about the benefits of the mix-and-match approach to the vaccine, in which someone gets a different type of booster, the evidence at this time is preliminary. However, it does appear that mixing two different types of COVID-19 vaccine results in a stronger immune response than when matching the booster to the original vaccine. Boosters of all three vaccines have received the green light. However, the Pfizer and Moderna booster doses of the mRNA vaccine appear to be more effective than the Johnson & Johnson vaccine.

Although this is a column about booster shots, we want to once again urge our readers to please get vaccinated if their age and health conditions allow it. The trio of vaccines that the FDA has approved are highly effective in preventing severe illness and hospitalization in those who become infected with the coronavirus. It’s tragic, but those who are unvaccinated are 10 times more likely to develop severe disease that requires them to be hospitalized.

To learn more about the vaccines and for the latest information visit UCLA Health's COVID-19 Vaccine Info Hub.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA 90025. Owing to the volume of mail, personal replies cannot be provided.)