Adult COVID-19 Booster Vaccine: What You Need and Want to Know

Have you gotten your COVID-19 booster shot yet? Here’s why you should, how to prep and what to expect.

The Facts

  • Brand:
    • Pfizer BioNTech COVID-19 Vaccine
    • Moderna COVID-19 Vaccine
    • (Johnson & Johnson) Janssen COVID-19 Vaccine
  • Type:
    • mRNA
      • Pfizer BioNTech COVID-19 Vaccine
      • Moderna COVID-19 Vaccine
    • Viral Vector
      • Johnson & Johnson’s Janssen
  • Authorization: Emergency Use Authorization granted by FDA
  • Age Group: 18 years and older
  • Dose:
    • Pfizer BioNTech: 30 mcg (0.3 mL), same dose as two-dose vaccine series
    • Moderna: 50 mcg (0.5 mL), ½ of 100 mcg (1 mL) dose as two-dose vaccine series
    • Johnson & Johnson’s Janssen: 50 mcg (0.5 mL), same dose as single-dose vaccine series
  • Administration:
    • NOTE: The CDC states that the booster dose does NOT need to be the same brand or type of vaccine as the primary vaccination (single-dose or two-dose series); a mix and match approach is fine
    • Pfizer BioNTech: ≥6 months, 6 months after 2nd dose
    • Moderna: ≥6 months, 6 months after 2nd dose
    • Johnson & Johnson’s Janssen: ≥2 months, 2 months after single dose


  • Healthcare Systems
    • Healthcare providers or regional/national healthcare systems that administered the vaccine will likely be provide the booster dose
  • Cost: Free

The Data

  • While COVID-19 vaccination is effective in protecting against the virus and preventing severe disease, studies by the three approved vaccine companies show the level of protection may decrease over time and might not be as effective against some variants
  • This to be particularly true for:
    • Fully vaccinated individuals 65 and older
    • Healthcare and other frontline workers
  • A decrease in effectiveness over time occurs for two reasons:
    • Immunity decreases as time passes since completing your primary vaccine series; this is true for many vaccines, including flu, tetanus, and hepatitis
    • Aggressive nature of variants, including Delta
  • Clinical trial data showed that “a booster shot increased the immune response in trial participants who finished a Pfizer-BioNTech or Moderna primary series 6 months earlier or who received a J&J/Janssen single-dose vaccine 2 months earlier.” Thus, the booster provides more protection against the virus and variants.
  • Omicron and Future Variants
    • Emergence of the Omicron variant underscores the importance of getting the booster to increase your protection and immune response
    • Case in point: Omicron data from South Africa suggests increased transmissibility and that the variant could potentially evade current vaccination immunity levels
    • Best to booster up to maximize your immunity until more data is available


  • Short-term (hours to days after injection):
    • Side-effects were similar to those after the single-dose or two-dose primary vaccine series
    • Reported overall as mild to moderate, with the most common being
      • Fever
      • Headache
      • Tiredness/Fatigue
      • Pain at Injection Site

Note: These reactions are common and a normal sign that your body is building protection against COVID-19. Serious short-term side-effects are rare, but include anaphylaxis, TTS, and myocarditis

  • Long-term (within first six weeks after injection):
    • To date, there are no reported long-term side-effects from the COVID-19 vaccine
  • Consult a physician before getting a booster if
    • Immunocompromised due to
      • Cancer treatment
      • Organ transplantation
      • Trouble breathing or anaphylaxis after receiving primary COVID-19 vaccine series

Five Reasons Adults 18 and Older Should Get A Booster Shot

1. Maximize protection of themselves and their health

2. Maximize protection of whole family/household

3. Maximize protection of their community: community immunity happens when so many members of a community are vaccinated that COVID-19 disappears or is rarely contracted

4. Stay in work and/or school when exposed to COVID-19: while you are still technically “fully vaccinated” without the booster, not getting it means you’re more likely to fall ill and thus have to miss work or school

5. Have maximum immune protection again developing variants like Omicron and others that will follow

Five Tips for Preparing for Your Booster Shot

1. Bring your CDC COVID-19 Vaccination Record card to your booster shot appointment

2. DO NOT take a pain reliever before injection to try to prevent side-effects

3. Be prepared to wait 15-30 minutes post-injection for observation by a healthcare professional

4. Use these helpful tips to relieve side-effects:

  • Ask your physician about taking an over-the-counter
    • Pain reliever
    • Antihistamine
  • Follow these health tips

5. Use v-safe to report any side-effects to the CDC through the system’s daily health check-ins


AARP: What Are the Side Effects of Booster Shots?

CDC: COVID-19 Vaccine Booster Shots

CDC: Key Things to Know About COVID-19 VaccinesCOVID-19 Vaccine Booster Shots

CDC: Possible Side Effects After Getting a COVID-19 Vaccine

CDC: Recommended Adult Immunization Schedule for ages 19 years or older, United States, 2021

CDC: State and Territorial Health Websites

Columbia DocTalks: Children and COVID-19

New York-Presbyterian Hospital: Two leading pediatric specialists answer parents’ questions about the COVID-19 vaccine for children ages 5 to 11