• The U.S. Food and Drug Administration (FDA) has approved a new COVID-19 vaccine from Novavax, offering Americans ages 12 and up a viable alternative to the messenger RNA (mRNA) vaccines from Pfizer and Moderna.
• In clinical trials, the Novavax COVID-19 vaccine has proven safe and highly effective in protecting people from severe COVID-19 and hospitalization.
• Separately, the FDA has updated recommendations for the Johnson & Johnson (J&J) vaccine, saying it should be administered to adults only by request or as a last resort relating to concerns with other vaccines.

The COVID-19 vaccination landscape has shifted in recent months. In July, the FDA approved one new vaccine from Novavax for people ages 18 and up — and then in August approved the vaccine for adolescents 12 through 17. Separately, in May, the FDA introduced new limits for the Johnson & Johnson vaccine due to safety concerns.

Public health advocates from agencies including the Centers for Disease Control and Prevention (CDC) have backed the FDA’s emergency use authorization of the Novavax vaccine. This authorization gives Americans a new immunization alternative to long-available mRNA vaccines from Pfizer and Moderna. The Novavax vaccine had already been approved for use in 40 other countries prior to the FDA’s authorization.

“The Novavax COVID-19 vaccine offers an option to individuals who may be allergic to a component in the mRNA vaccines, or who have a personal preference for receiving a vaccine other than an mRNA-based vaccine,” according to a statement from the U.S. Department of Health & Human Services.

Johnson & Johnson Vaccine Still FDA-Authorized, but With Warnings

The FDA issues emergency use authorizations for vaccines, medications, and treatments that are scientifically proven to have benefits that outweigh any potential risks. The agency continues to monitor drugs that receive emergency authorizations and may change its recommendations based on new discoveries.

Such is the case for the Johnson & Johnson vaccine, which received an emergency use authorization in February 2021. Though the J&J vaccine remains FDA-authorized, the agency now advises that health care providers give that particular shot only to people over 18 who will not or cannot (for medical reasons) receive one of the other vaccines. The FDA’s updated guidance is based on research linking the J&J shot to rare instances of life-threatening blood clots and the availability of other COVID-19 vaccines without this issue.

Who Can Get the Novavax COVID-19 Vaccine?

The FDA has authorized the Novavax COVID-19 vaccine for unvaccinated adults and adolescents ages 12 and up. Like the other vaccines, this one is administered via a shot in the upper arm.

The primary series for the Novax is two doses, given three to eight weeks apart. According to the CDC, people who are moderately or severely immunocompromised also should receive two doses, given three weeks apart.

Boosters for Novavax May Come Later

Novavax has submitted an application to the FDA for use of its vaccine as a booster, both for people who received Novavax and and people who received other vaccines as their primary series. Boosters are additional shots administered to people who’ve already received their primary series of a vaccine to ensure their immune system remains primed to fight the virus as their antibodies against it naturally dwindle.

Additionally, Novavax initiated a global clinical trial to gauge the safety and effectiveness of its vaccine on infants and adolescents ages 6 months to 11 years. The company seeks to enroll 3,600 participants from countries including the U.S., Mexico, South Africa, United Kingdom, and others. Results are expected in 2023.

Protein-Based Vaccines vs. mRNA: What’s the Difference?

Novavax’s new vaccine takes a tried-and-true protein-based vaccine approach, instead of using the newer mRNA technology found in the Moderna and Pfizer vaccines. Scientists have used this protein-based technique for decades to develop safe and effective vaccines against infectious diseases including diphtheria, tetanus, hepatitis B, whooping cough, and the flu. Protein-based vaccines are also called protein subunit vaccines.

Broadly speaking, vaccines are designed to work in the same way: They effectively introduce a harmless piece of a virus or bacteria to a person’s body, thereby teaching their immune system how to recognize that organism as a threat. The immune system then develops a way to fight it, called an immune response.

The mRNA vaccines from Pfizer and Moderna don’t actually put any traces of SARS-CoV-2 — the coronavirus that causes COVID-19 — in your body. Rather, they introduce a molecule called messenger RNA. This messenger acts as a sort of blueprint, instructing cells within the body on how to create a coronavirus-like protein. Once those cells produce that protein, the vaccine recipient’s immune system kicks in: It sees traces of this new, foreign — and potentially dangerous — protein and devises an action plan to destroy it. That way, if a person is later infected by the real coronavirus, their body will be prepared to fight it.

Instead of using mRNA, the Novavax vaccine introduces a coronavirus spike protein — in this case, a synthetic one made from insect cells. The vaccine also contains what’s called a Matrix-M adjuvant, derived from soapbark trees native to Chile. According to Novavax, this adjuvant strengthens a vaccinated person’s immune response. You can read more about vaccine adjuvants from the CDC.

As with the mRNA vaccines, the Novavax shot teaches the vaccine recipient’s immune system what the coronavirus looks like, so the immune system can launch an effective immune response should the real virus come calling.

Is the Novavax Vaccine Effective in Preventing COVID-19?

As with other FDA-approved vaccinations and medications, the Novavax COVID-19 vaccination first had to prove that it was effective and safe.

According to the World Health Organization (WHO), two separate clinical trials found that the vaccine was 90 percent effective at preventing mild, moderate, and severe disease. When Pfizer and Moderna received their respective FDA authorizations last year, Pfizer’s efficacy rate for adults was 95 percent and Moderna’s was 94 percent.

The Novavax vaccine was shown to be 78 percent effective in adolescents aged 12 through 17 while the delta variant of the coronavirus was circulating.

Notably, all of this data on effectiveness was collected prior to the dominance of the omicron variant and subvariants of the SARS-CoV-2 virus. Some of those variants have proven more capable of breakthrough infections — that is, infecting people who’ve been fully vaccinated.

Though breakthrough infections occur, health experts still agree that being vaccinated and receiving boosters on a regular schedule remains the best strategy for preventing severe illness from COVID-19, requiring hospitalization, and developing long COVID.

Does the Novavax COVID-19 Vaccine Have Side Effects?

According to the FDA’s fact sheet on the Novavax vaccine, general side effects include:

• Fever
• Chills
• Fatigue
• Headache
• Muscle pain
• Joint pain
• Nausea and vomiting

These side effects are similar to those of the Moderna and Pfizer vaccines. According to the CDC, these side effects are generally mild and may last a few days, though some may interfere with a person’s ability to perform daily activities. They’re also more common following the second dose.

The CDC cautions that severe allergic reactions to the vaccine are possible, though they’re very rare. Signs of severe allergic reactions include:

• Difficulty breathing
• Swelling around the face and throat
• Fast heartbeat
• Rash covering the body
• Dizziness
• Weakness

Researchers have reported other extremely rare adverse events following a Novavax vaccination affecting the heart, including myocarditis (inflammation of the heart muscle) and pericarditis (swelling and irritation of a membrane surrounding the heart called the pericardium).

Among 40,000 people who received the Novavax vaccine in clinical trials, approximately four to six developed myocarditis or pericarditis, which is well below 1 percent of all the vaccine recipients, according to Dr. Sandra Fryhofer. Dr. Fryhofer is the American Medical Association's liaison to the Advisory Committee on Immunization Practices (ACIP) and a member of ACIP’s COVID-19 Vaccine Workgroup.

“Unfortunately, as we’ve seen with the mRNA vaccines, there have been reports of myocarditis and pericarditis after Novavax during the clinical trials,” Dr. Fryhofer said. “We know that the risk of heart complications is higher after COVID disease than after mRNA COVID vaccination among males and females of all ages.”

According to the CDC, none of the FDA-approved COVID-19 vaccines contain any of the following ingredients:

• Preservatives
• Antibiotics
• Medicines or therapeutics
• Tissues, such as aborted fetal cells or any materials from any animal
• Food proteins, such as eggs, gluten, or nut products
• Metals
• Latex

Talk to Your Doctor About Vaccination Options

COVID-19 vaccines are effective at protecting people from getting seriously ill, being hospitalized, and dying from the coronavirus. If you have not received an mRNA COVID-19 vaccination due to health issues such as allergies, or for personal reasons, speak with your health care provider about whether the Novavax COVID-19 vaccine is a good option for you.

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