This photo shows the Food and Drug Administration (FDA) and Novavax logos on the back of medical syringes and vials.
Pavlo Gonchar | LightRocket | Getty Images
Food and Drug Administration approved Novavax‘s two-dose vaccine for adults 18 and older, the fourth Covid shot to receive emergency approval in the US since then pandemic started
FDA decision independent vaccine expert committee vHe preferred Novavax’s shot In early June, after an all-day public meeting where they weighed data on the vaccine’s safety and effectiveness in preventing Covid.
The Centers for Disease Control and Prevention still needs to sign off on the Novavax vaccine before pharmacies and other healthcare providers can administer the vaccine. FDA approval for the Novavax vaccine was delayed for weeks as it was reviewed by the agency changes in the company’s production process.
Novavax was one of the early participants in the US government’s 2020 race to develop a Covid vaccine and received $1.8 billion in taxpayer funding from Operation Warp Speed. However, the small Maryland biotech has struggled to get into production quickly, and its clinical trial data has been read far behind Pfizer or Moderna.
Novavax shots received FDA approval at a time when approximately 77% of adults 18 and older are already fully vaccinated. However, 27 million adults still haven’t been shot once. Dr. Peter Marks, a top FDA official, said the Novavax vaccine would appeal to unvaccinated people who prefer a shot that is not based on the messenger RNA technology used by Pfizer and Moderna.
How Novavax is different
The Novavax vaccine is based on more traditional protein technology used for decades in hepatitis B and HPV vaccines, while Pfizer and Moderna are the first FDA-approved vaccines using mRNA.
The Pfizer and Moderna vaccines use mRNA, a molecule encoded with genetic instructions, to tell human cells to make copies of a viral particle called a spike protein. The immune system responds to these copies of the spike, preparing the human body to attack the actual virus.
Novavax removes copies of the virus from human cells. The spike’s genetic code is inserted into an insect virus that infects moth cells, producing copies that are then purified and removed during the production process. Ready-made copies of the spike are injected into the human body and create an immune response against Covid.
The Novavax vaccine also uses an additional ingredient called an adjuvant, which is extracted and purified from the bark of a tree in South America to create a broader immune response. Shots contain 5 micrograms of spiked copy and 50 micrograms of excipient.
Efficacy and safety
According to clinical trial data from the US and Mexico, two doses of the Novavax vaccine were 90% effective in preventing Covid and 100% effective in preventing severe disease. However, the test was conducted between December 2020 and September 2021, months before the omicron variant became dominant.
Novavax did not present any data on the effectiveness of the shot against this variant at an FDA committee meeting in June. However, the vaccine will be less effective against omicron, as with the Pfizer and Moderna shots. Omicron is so different from the original strain of Covid that antibodies produced by vaccines have difficulty recognizing and attacking the variant.
Novavax published data in December showing that a third shot boosted the immune response to levels comparable to the first two doses, which were 90% effective against the disease. The company plans to ask the FDA to approve a third dose of the vaccine.
The FDA approval for the Novavax vaccines comes as the US prepares for an updated Covid shot to target the omicron BA.4 and BA.5 variants to boost protection against the virus. The Novavax vaccine, like all other shots, is based on the original version of the virus that first appeared in Wuhan, China. The effectiveness of Covid vaccines against mild disease has declined significantly as the virus has evolved, although they still generally protect against severe disease.
Novavax provided the data FDA committee meeting at the end of June demonstrated that the third dose of the vaccine induced a strong immune response against omicron and its subvariants. The committee members were impressed with the company’s information about omicron.
The Novavax vaccine also carries a risk of heart inflammation for young men, known as myocarditis and pericarditis, similar to shots from Pfizer and Moderna. Myocarditis is an inflammation of the heart muscle, and pericarditis is an inflammation of the outer membrane of the heart.
FDA officials noted four cases of myocarditis and pericarditis from a clinical trial of Novavax in young men ages 16 to 28. People who develop heart inflammation as a side effect of Covid vaccines are usually hospitalized for a few days as a precaution, but then recover.
The FDA has released an information sheet for healthcare providers warning that clinical trial data show an increased risk of myocarditis with the Novavax vaccine. According to the FDA, people who experience chest pain, shortness of breath, and feelings of a fluttering or pounding heart should seek immediate medical attention.
Into case of mRNA captures, the CDC found that the risk of myocarditis is higher from Covid infection than from the vaccine. Myocarditis is usually caused by viral infections.
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