What are the bivalent COVID boosters? 

The bivalent boosters are updated vaccines that target 2 Omnicron sub variants, BA.4 and BA.5, the most contagious versions of SARS-CoV-2 to date, with BA.5 accounting for nearly 90% of cases in the United States. Half of the vaccine targets the original strain of COVID-19 (BA.1), while the other half targets the subvariant strains, which are predicted to continue circulating this fall and winter. The boosters, one from Pfizer for ages 12+ and the other from Moderna for ages 18+, are authorized under an FDA emergency use authorization 

Who can get the booster?  

  • Pfizer: authorized for patients 12 years or older. 
  • Moderna: authorized for patients 18 years or older. 
  • Patients must complete a primary COVID-19 vaccine series before getting the booster.  
  • Children 5-11 who received a primary Pfizer series should receive the original monovalent booster.  

When should you get it? 

Patients should wait at least 2 months from last COVID vaccine before getting the bivalent booster. If you are anticipating travelling or experience larger in person gatherings, it is recommended to receive a booster at least 2 weeks prior to maximize your protection from being infected. 

Should you get boosted if you’ve already had COVID-19? 

Yes, however patients should wait until they are fully recovered from acute illness and are out of isolation. The CDC advises to wait 3 months after COVID-19 infection to get the booster. 

What are the side effects? 

The bivalent studies listed common side effects including:  

  • Fatigue
  • Headache 
  • Muscle and joint aches 
  • Chills 
  • Nausea/ vomiting 
  • Fever  

A very rare but serious side effect of the mRNA COVID vaccines is myocarditis, or inflammation of the heart muscle. Researchers reported no cases of pericarditis or myocarditis with the additions of BA.4 and BA.5 spike protein sequences in the most recent study  

Can I get a COVID booster at the same time as a flu shot? 

The CDC states that it is safe to get a flu shot at the same time as any COVID vaccine, in fact it is encouraged because the 2 viruses will be circulating at the same time. It is also acceptable to get a COVID booster with other needed vaccines. The only exception is the monkeypox vaccine, it is recommended to wait 4 weeks after receiving a monkeypox vaccine to receive a COVID booster. However, if you receive a COVID booster first, you do not need to wait to receive a monkeypox vaccine 


Written By: 

Viktoriya Shevchyk 

PharmD Candidate 2023  

Philadelphia College of Pharmacy  



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