Everything You Need To Know About The Bivalent COVID-19 Booster

Three years on, news about COVID-19 doesn’t seem to be getting any less overwhelming. Scientists are innovating daily as more research is carried out to understand the novel virus and how to prevent and protect against it.

New strains and substrains mean we need to innovate vaccines and booster shots. The Omicron subvariant that appeared in late 2021 has proven the most contagious form of the virus yet, accounting for up to 80% of COVID-19 cases in the US.¹

The COVID-19 vaccines have effectively slowed the spread of the virus and prevented severe infections to some degree. But vaccine boosters are needed to optimize your immunity and help avoid reinfections or hospitalization.

The bivalent COVID-19 booster includes the Moderna and Pfizer vaccines you are already familiar with. The Moderna COVID-19 Vaccine, Bivalent, and the Pfizer-BioNTech COVID-19 Vaccine, Bivalent, are single booster doses approved by the US Food and Drug Administration (the FDA) for use in people as young as five.

The bivalent booster protects you against the Omicron strain, substrains, and earlier strains.

Here are answers to ten of the most pressing questions about the bivalent COVID-19 booster.

How is this booster different?

The bivalent boosters differ from others because they contain two types of messenger RNA (mRNA). These protect you against the original virus strain and the Omicron variant.

This booster generally provides better protection against COVID-19.² It gives you an added layer of protection if you’ve already had your original vaccine shots or other booster shots.

Are these booster shots safe?

The Centers for Disease Control and Prevention (CDC) has repeatedly confirmed COVID-19 vaccines are safe. The FDA has put the vaccines through several safety tests and confirmed their safety.³

Moderna and Pfizer used the same kind of technology to develop the original COVID-19 and bivalent vaccines.

Severe side effects from the COVID-19 vaccine or booster shots are very rare. However, speak to your doctor if you experience unexplained symptoms after a vaccine shot. 

Are these booster shots effective?

Understandably, many people have questions about the effectiveness of booster shots.

The coronavirus responsible for COVID-19 has continued to mutate since its inception. This is why we need booster shots — to ensure our immune systems can fight the virus.

In a 2021 study by Pfizer,⁴ researchers observed a 95.6% effectiveness against the COVID-19 virus.

Within two weeks of taking the bivalent booster shot, your immune system escalates to offer a high level of protection against all current known strains of COVID-19.

Scientists are still determining how long the booster will provide protection. Research shows it should provide peak protection for two to four months and good protection for four to six months. Protection reduces after six months, but the vaccine is still effective and provides more protection than if you hadn’t gotten a booster shot.

Data shows the bivalent booster offers better protection against the Omicron variant than the first booster vaccines.⁵

Why weren’t these Omicron boosters tested on humans?

People around the world first came to know about the Omicron variant in late 2021. Since then, researchers and scientists across the globe have been working tirelessly to understand the new strain and how best to protect people.

Vaccines undergo several trials and tests to prove their safety and effectiveness. Animal trials are some of the earliest. Proceeding to human trials takes longer, and during this time, the virus could continue to spread and mutate.

The bivalent vaccine’s safety and efficacy were confirmed using data from animal studies and previous COVID-19 vaccine studies.

This strategy has also been used when developing influenza vaccines. The flu shot is one of the most common vaccines administered in the US. Flu shots are regularly tweaked based on old data without using further clinical studies. They remain safe and effective.

Who is eligible for the bivalent COVID-19 booster?

You must be fully vaccinated to qualify for the bivalent COVID-19 booster. You are fully immunized if you have received two full doses of the Moderna, Pfizer, Novavax, or BioNTech vaccine. A single dose of the Johnson & Johnson vaccine means you are fully vaccinated.

You don’t have to get a booster to qualify as fully vaccinated.

You can use the CDC tool to check your vaccine status if you’re unsure.⁶

You should get the bivalent COVID-19 booster shot even if you’ve already been infected with the Omicron variant. You could be reinfected and experience severe symptoms, even if you didn’t have severe symptoms when you were first infected.

The bivalent booster is safe for anyone over the age of five.⁶

When should you get your booster?

The CDC advises getting a booster at least two months after your most recent COVID-19 vaccine. You need to be fully vaccinated to qualify for a booster shot, so you’ll need to wait two months after you’ve received a dose that makes you fully vaccinated or another booster shot.⁷

You may be able to wait up to four months from your last booster to get a second booster, as your last dose will protect you.

It’s safe for you to get a booster shot if you’ve just had your flu shot. You can even get them simultaneously if your healthcare provider offers both services.⁸

Does the bivalent COVID-19 booster cause any side effects?

All COVID-19 vaccines can cause minor side effects in some people. So do the bivalent boosters.

A study of side effects caused by earlier versions of the Moderna bivalent booster showed adverse effects such as fatigue, nausea, and fever. You may also experience some pain, swelling, and redness around the injection site.²

Like other doses of the COVID-19 vaccines, severe side effects of the bivalent booster are very rare.

Can you get a booster if you’ve just had COVID-19?

Leaving at least three months between a COVID-19 infection and the bivalent booster shot is recommended. Count the three months from when your symptoms started. You need to give your immune system time to recover from the aftereffects.

If you didn’t develop any symptoms, wait three months after receiving a positive test result.⁶

It’s still possible to get COVID-19 after your first vaccine shots because your level of protection against the virus decreases over time. Staying up to date with your booster shots will maintain your immunity against circulating variants.

Can you mix and match vaccines?

Having two shots of the same vaccine was recommended for initial vaccine doses. However, you can mix and match your booster doses.

The FDA and CDC confirm that combining booster shots is safe and effective. This allows people to take the available booster shots as soon as possible.⁹

Mixing and matching vaccines won’t reduce the vaccine’s effectiveness. Research shows this could cause a more robust immune system response in some cases.

A 2022 study showed that mixing and matching your primary and booster vaccines led to higher antibody markers 29 days after the booster. This may indicate mixing and matching is slightly more effective.¹⁰

Ask your doctor for more information about having a booster shot from a different manufacturer.

Why should you have a new booster dose?

Being wary about getting a new booster dose is understandable. You may have assumed you would only ever need your primary shots. However, the novel virus is still being researched. Scientists and researchers have a better understanding of the virus today than before.

Having booster shots is recommended, even if you are fully vaccinated or have had the COVID-19 virus. While getting a booster shot doesn’t provide 100% protection against the coronavirus, it does help prevent severe symptoms that can lead to hospitalization or death.

Your primary vaccine shots protect you against the first known SARS-Cov-2 virus, but they may not provide effective protection against other variants, like Omicron. Your immune system may also provide weakened protection over time, exposing you to infection.

The bivalent booster currently offers the most protection for current (known) COVID-19 strains.

The lowdown

Fewer than 5% of the US population have received their bivalent COVID-19 booster shots, despite a wealth of research indicating their importance. This threatens our progress in fighting the virus’s deadly effects.

Primary vaccines were designed to fight the earliest COVID-19 variants, but these no longer appear to be circulating. More recent strains, like the Delta and Omicron variants, are now commonplace.

Data from the effects of the original vaccines and the technology used to create them helps scientists design new boosters.

The bivalent COVID-19 booster doesn’t provide complete protection against new variants but gives you the best chance of preventing severe symptoms and complications. For as long as the pandemic lasts, adhere to other COVID-19 precautions, such as social distancing, wearing your mask, and regularly washing your hands.

  1. The omicron booster: Your questions answered | Yale Medicine

  2. Coronavirus (COVID-19) update: FDA authorizes Moderna and Pfizer-BioNTech bivalent COVID-19 vaccines for use as a booster dose in younger age groups — FDA news release | U.S. Food & Drug Administration

  3. Safety of COVID-19 vaccines | Centers for Disease Control and Prevention (CDC)

  4. Pfizer and BioNTech announce phase 3 trial data showing high efficacy of a booster dose of their COVID-19 vaccine | Pfizer

  5. A bivalent omicron-containing booster vaccine against Covid-19 (2022)

  6. Stay up to date with COVID-19 vaccines including boosters | Centers for Disease Control and Prevention (CDC)

  7. Interim clinical considerations for use of COVID-19 vaccines currently approved or authorized in the United States | Centers for Disease Control and Prevention

  8. Can you get the new COVID-19 booster at the same time as a flu shot? | The Brink

  9. Coronavirus (COVID-19) update: FDA takes additional actions on the use of a booster dose for COVID-19 vaccines | U.S. Food & Drug Administration

  10. Mix-and-match trial finds additional dose of COVID-19 vaccine safe, immunogenic | NIH: National Institute of Health

Toketemu Ohwovoriole is a healthcare writer who has spent the last six years creating content for companies and publications around the globe. She has been featured in The Huffington Post, Insider, Verywell, and other major publications. Her previous work delves into the mental and physical health effects of birth control, overall wellness, and sensitive women's healthcare issues.

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