The Bivalent Booster is Extra Spicy 🔥

According to informal posts on social media, the Omicron-specific booster is hitting hard.

Moderna bivalent booster effects

Three shots of Pfizer had no symptoms for me, but the recent Moderna bivalent booster gave me hell of a headache and sore muscles. Heads up – this round of boosters may not be easy as the previous ones.

A cursory reading of random tweets suggest that the most common side effects are fever, muscle aches, joint pain, and fatigue.

omicron covid booster

Bivalent booster side effects

10/10 Would Recommend

Overall, the bivalent shot hit me a bit harder than the previous ones, but it’s been totally fine. 10/10 would recommend.

booster side effect joint ache, exhaustion

USA Bivalent Booster Different From Elsewhere

The bivalent booster available in Europe, Canada, and Australia is made for BA.1 while the bivalent booster available in United States is made for BA.4/BA.5 (tested on eight mice 🐁).


Last month, the “Pfizer-BioNTech COVID-19 Vaccine, Bivalent (Original and Omicron BA.4/BA.5)” (in short: “COVID-19 Vaccine, Bivalent“) received emergency use authorization from the U.S. FDA for use as a booster dose in individuals aged twelve years of age and older. One dose contains 15 mcg of “a nucleoside-modified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2 Wuhan-Hu-1 strain (Original)” and 15 mcg “of modRNA encoding the S glycoprotein of SARS-CoV-2 Omicron variant lineages BA.4 and BA.5 (Omicron BA.4/BA.5)”.

The Pfizer updated booster authorized in the United States is different from the one authorized for use in the European Union and in the United Kingdom, as the latter contains as second modRNA component 15 mcg of modRNA enocoding the S gylcoprotein of the earlier BA.1 variant.


In August and September 2022, a bivalent version of the vaccine (Moderna COVID-19 Vaccine, Bivalent) containing elasomeran/elasomeran 0-omicron (Spikevax Bivalent Zero/Omicron)was authorized for use as a booster dose in individuals aged 18 years of age or older in the United Kingdom, Switzerland, Australia, Canada, the European Union, and the United States.

The version of the Moderna bivalent vaccine in the United States uses Omicron BA.4/BA.5 for the second component of the vaccine. In other countries the second component is based on the Omicron BA.1 variant.


On September 1, 2022, Health Canada authorized an adapted version of the Moderna Spikevax COVID-19 vaccine. This transfection agent known as a bivalent vaccine targets the original SARS-CoV-2 virus from 2019 and the Omicron (BA.1) variant, and is authorized for use as a booster dose in individuals 18 years of age or older.

Health Canada has determined that the bivalent Moderna Spikevax booster is safe and effective.

Bivalent COVID vaccine in Canada

“All COVID-19 vaccines approved in Canada are safe and effective including the bivalent COVID-19 vaccine which is adapted to provide increased protection against current Omicron variants.

Five Shots, Y’all

5 doses of covid mrna vaccines

Get the Flu Shot and Bivalent COVID Booster at the Same Time!

During a White House briefing on the new COVID-19 bivalent booster shots, Dr. Ashish Jha, Joe Biden’s COVID-19 response coordinator, urged Americans to get a flu shot and a COVID-19 shot at the same time, claiming that’s why “God gave us two arms.”

Covid Booster Extra Spicy