The Centers for Disease Control and Prevention on Tuesday signed Novaxa two-dose Covid-19 vaccine as a primary series for adults, offering people who have not been vaccinated the opportunity to get vaccinated based on traditional technology used for more than 30 years.
The CDC Committee of Independent Advisers voted unanimously to recommend a vaccine for people 18 years of age and older after reviewing the vaccines’ safety and effectiveness during a hours-long public meeting on Tuesday. CDC Director Dr. Rochelle Walensky later in the evening supported the recommendation, the final step in the US authorization process.
The CDC said in a statement that the vaccine will be available to the public in the coming weeks. The Biden administration has received 3.2 million doses of the Novavax vaccine to date, according to the Department of Health and Human Services.
The CDC approval completes a two-year journey for Novavax, one of the early entrants in the U.S. race to produce a vaccine to protect against Covid-19. The small Maryland biotech received $1.8 billion in taxpayer money from Operation Warp Speed but struggled to build its manufacturing base and ended up falling behind Pfizer and Moderna.
The Novavax vaccine will arrive in the US at a time when more than three-quarters of US adults, 77%, are now fully vaccinated with Pfizer, Moderna and, to a much lesser extent, Johnson & Johnson, according to the CDC.
Walensky said in a statement that the Novavax vaccine would provide another option for people who don’t want to get shots from Pfizer and Moderna. Between 26 million and 37 million adults in the US are still unvaccinated, according to the CDC, but it’s not clear how many of those people will decide to take the Novavax vaccine.
“The main target population for Novavax will be between 10% and 13% of those who have not been vaccinated,” the doctor said. Oliver Brooks, member of the CDC committee on vaccines and chief medical officer of Watts HealthCare Corporation in Los Angeles.
“I understand that we are really focused on this population with the hope that maybe this protein subunit vaccine will turn them from unvaccinated to vaccinated,” Brooks said.
According to clinical trial data, Novavax vaccines were 90% effective in preventing disease in general and 100% effective in preventing severe disease when the alpha variant of Covid dominated. The company has not published data on the actual effectiveness of its shots against omicron and its sub-variants.
But the Novavax vaccine appears to elicit a strong immune response against Omicron and its subvariants, suggesting that it is effective against this variant. Data on the company’s immune response to omicron impressed members of the Food and Drug Administration’s vaccine committee last month.
The FDA warned in a fact sheet for healthcare professionals that the Novavax vaccine appears to carry a risk of an inflammation of the heart called myocarditis. FDA officials noted four cases of myocarditis and pericarditis — swelling of the membrane surrounding the heart — in a Novavax clinical trial in young men aged 16 to 28 years.
The Pfizer and Moderna vaccines also pose an increased risk of myocarditis for adolescent boys and young men after the second dose. The CDC has found that Covid infection carries a greater risk of heart inflammation than vaccination with Pfizer or Moderna shots. Myocarditis is usually caused by viral infections.
The Novavax vaccine uses a different platform than the Pfizer and Moderna vaccines. According to the CDC, the Novavax vaccine is based on protein subunit technology that has been in use for more than 30 years, dating back to the first licensed hepatitis B vaccine. This technology is also used in flu and whooping cough vaccines.
Novavax makes inactive copies of the virus’s spike protein by inserting the genetic code into an insect virus that infects moth cells. Copies of the spikes are harvested and purified from these cells for vaccine.
The spike protein is the mechanism that the virus uses to enter human cells. The spike copies in the vaccine prepare the body’s immune system to produce antibodies that block the virus from entering human cells. The Novavax vaccine also has an additional ingredient called an adjuvant, which is derived from the bark of a South American tree, to induce a broader immune response to fight the virus.
In contrast, Pfizer and Moderna’s vaccine uses messenger RNA technology. Their injections deliver messenger RNA to human cells, which then make inactive copies of the spike protein to trigger an immune response to fight the virus. The Pfizer and Moderna vaccines are the first mRNA vaccines to receive FDA approval.
Novavax injections are also stored at normal temperature in the refrigerator, while Pfizer and Moderna injections require sub-zero temperatures.
Although the Food and Drug Administration (FDA) has repeatedly recognized Pfizer and Moderna vaccines as safe and effective vaccines for all age groups in the US, health officials have struggled to convince millions of skeptics to get vaccinated.
Ahead of the expected fall vaccination campaign, the US plans to refine vaccines to target the more transmissible omicron sub-variants BA.4 or BA.5 that are currently dominant. Covid vaccines are less effective at preventing omicron infection due to the variant’s many mutations, but overall they still protect against severe forms of the disease.
U.S. health officials believe that re-formulating the vaccine with omicron variants, as well as the original strain that emerged in Wuhan, China, in 2019, will provide stronger protection against the virus this fall.
The Novavax vaccine, like any currently approved Covid vaccine, is based on the original strain of the virus that first emerged in China. Like Pfizer and Moderna, Novavax is developing vaccines that target the omicron variant, but company executives said it’s unclear whether they need to release an updated vaccine because the company’s current vaccine elicits a broad immune response against that variant.
The CDC and FDA have not approved mixing and matching the Novavax vaccine with Pfizer and Moderna vaccines as a booster. Novavax said it plans to ask the FDA to allow a booster shot of its vaccine.