What You Need to Know about COVID-19 Vaccine Booster Shots

Woman with band aid on her arm after covid shot
Concerns about waning COVID-19 vaccine immunity and the rapid spread of the Omicron variant is behind the CDC push for booster shots.

The rapid spread of the highly infectious Omicron variant, along with concerns about waning vaccine immunity, have led the Centers for Disease Control and Prevention (CDC) to again bolster its recommendations for COVID-19 vaccine boosters and encourage everyone age 12 and older to get a third shot. 

“It is critical that we protect our children and teens from COVID-19 infection and the complications of severe disease,” said CDC Director Dr. Rochelle Walensky, who signed off on the recommendation of the Advisory Committee on Immunization Practices (ACIP) Jan. 5.

“We now recommend that all adolescents aged 12-17 years should receive a booster shot 5 months after their primary (Pfizer) series. This booster dose will provide optimized protection against COVID-19 and the Omicron variant,” she said.

Here are more things to know about COVID-19 vaccine boosters.

Why are COVID-19 vaccine booster shots needed?

While the FDA-approved COVID-19 vaccines work well to prevent severe illness, hospitalization, and death, even against highly transmissible variants, medical and public health experts have determined protection against mild and moderate disease from the virus decreases over time following initial doses.

With waning immunity and mutations that appear to make variants such as Delta and Omicron more transmissible, breakthrough cases of COVID-19 are more likely and make booster doses necessary for additional protection.

Who is eligible for a COVID-19 vaccine booster shot and when should they get one?

Based on recent CDC recommendations, everyone 12 and older should get a booster 5 months after completing their primary COVID-19 Pfizer-BioNTech vaccination series. 

The booster interval recommendation for those who received the Johnson & Johnson vaccine is 2 months, and 6 months for individuals who received the Moderna shot. 

As proposed for immunocompromised adults, the CDC also recommends moderately or severely immunocompromised children 5–11 years old receive an additional primary dose of vaccine 28 days after their second shot.  At this time, only the Pfizer-BioNTech COVID-19 vaccine is authorized and recommended for children aged 5-11.

What are common side effects from the COVID-19 booster?

As with the initial vaccine series, people may experience side effects after getting a booster shot. These are normal signs that the body is building protection against the virus and should go away within a few days.

Some common side effects include pain, redness and swelling in the arm where you received the shot, tiredness, muscle pain, fever, chills, headache and nausea. 

Serious side effects causing long-term health problems are extremely unlikely following any vaccination, including the COVID-19 vaccine.

Which COVID-19 vaccine booster does the CDC recommend?

The CDC now recommends people get an mRNA vaccine and booster (Pfizer-BioNTech or Moderna) over the Johnson & Johnson shot. 

The new advice is in step with a recent recommendation by the Advisory Committee on Immunization Practices (ACIP) based on the latest evidence on vaccine effectiveness and safety, rare adverse events and consideration of the vaccine supply in the U.S.  

Still, due to the current state of the pandemic, the ACIP reaffirmed that receiving any vaccine is better than not being vaccinated and individuals unable or unwilling to receive an mRNA vaccine will still have access to Johnson & Johnson’s COVID-19 vaccine.

Will a COVID-19 booster protect against the Omicron variant?

Current COVID-19 vaccines are expected to protect against severe illness, hospitalizations, and deaths due to infection with the Omicron variant. But breakthrough infections in those fully vaccinated are likely to occur.

Data from South Africa, where Omicron was first identified, suggest the variant has increased transmissibility and the potential for immune evasion.

The rapid spread of Omicron – which now accounts for more than 70 percent of new COVID-19 cases in the U.S. – further highlights the importance of vaccination, boosters, and other prevention efforts to protect against COVID-19.  

South Shore Health infectious diseases expert Simone Wildes, MD, said the best protection for the virus is inoculation. 

“With the new omicron variant, this is the time to encourage people to get their vaccines. And if you’re eligible for a booster, I would encourage that as well,” she told The Patriot Ledger. “It’s not just to protect yourself, but also those around you who need extra protection.”