Novavax COVID-19 vaccine

The Novavax COVID-19 vaccine, sold under the brand names Nuvaxovid and Covovax, among others, is a subunit COVID-19 vaccine developed by Novavax and the Coalition for Epidemic Preparedness Innovations. Updated versions of the vaccine have been developed to provide coverage against the Omicron variant, with different formulas for 2023–2024 (containing a recombinant spike protein from lineage XBB.1.5) and 2024–2025 (containing recombinant spike protein from lineage JN.1).

Medical uses The Novavax COVID‑19 vaccine is indicated for active immunization to prevent COVID‑19 caused by SARS-CoV-2. In the US, Nuvaxovid is indicated for active immunization to prevent COVID‑19 caused by SARS-CoV-2 in adults aged 65 years of age and older. Nuvaxovid is also indicated for individuals aged 12 through 64 years of age who have at least one underlying condition that puts them at high risk for severe outcomes from COVID-19.

Efficacy

In December 2021, Novavax reported that its phase III trial showed the vaccine achieved its primary endpoint of preventing infection at least seven days after the second dose. Overall efficacy against different SARS-CoV-2s was 90.4% and efficacy against moderate-to-severe disease was 100%. A vaccine is generally considered effective if the estimate is ≥50% with a >30% lower limit of the 95% confidence interval. Efficacy is closely related to effectiveness, which is generally expected to slowly decrease over time.

Side effects The most common side effects include fever, headache, nausea, muscle and joint pain, tenderness and pain at the injection site, tiredness, and feeling unwell. Additional possible side effects include anaphylaxis (severe allergic reaction), paresthesia (unusual feeling in the skin, such as tingling or a crawling sensation) and hypoesthesia (decreased feeling or sensitivity, especially in the skin), and pericarditis (inflammation of lining around the heart). It has also been reported that myocarditis (inflammation of heart muscle cells) as reported incidence from receiving the NVX-CoV2373 vaccine. Tinnitus is a possible side effect.

Handling and administration The vaccine requires two doses and is stable at 2 to 8 °C (36 to 46 °F) refrigerated temperatures. The second dose can be administered three to eight weeks after the first dose. The vaccine injection is administered intramuscularly. There are no drug interactions that may affect the vaccine's efficacy if administered with other vaccines at the same time.

Pregnancy and breastfeeding The vaccine is a recombinant protein, not a live virus, therefore it will not replicate and spread to the infant. There are no studies conducted to trial the efficacy and safety of Novavax vaccine to people who are breastfeeding.

Technology NVX-CoV2373 has been described as both a protein subunit vaccine and a virus-like particle vaccine, although the producers call it a "recombinant nanoparticle vaccine". The vaccine is produced by creating an engineered baculovirus containing a gene for a modified SARS-CoV-2 spike protein. The spike protein was modified by incorporating two proline amino acids in order to stabilize the pre-fusion form of the protein; this same 2P modification is being used in several other COVID‑19 vaccines. The baculovirus is made to infect a culture of Sf9 moth cells, which then create the spike protein and display it on their cell membranes. The spike proteins are harvested and assembled onto a synthetic lipid nanoparticle about 50 nanometers across, each displaying up to 14 spike proteins. The formulation includes a saponin-based adjuvant named Matrix-M.

Matrix-M adjuvant is sourced from saponins originating from the Quillaja saponaria tree. Matrix-M adjuvant is combined with the spike protein from the SARS-CoV-2 antigen to induce immune response in body upon vaccination. The adjuvant primarily enhances local antibodies and immunity at the local site of injection and draining lymph nodes. The adjuvant demonstrates its protection against the virus by inducing innate immune system rapidly. At the local site of injection, the adjuvant recruits antigen presenting cells and attracts more T cells, such as CD4+ and CD8+ T cells. After entry of the vaccine nanoparticle containing the recombinant spike protein of the virus, it binds to ACE2 (angiotensin-converting enzyme 2) receptor to allow endocytosis and viral replication. However, upon endocytosis these viral particles are digested by lysosome and presented to MHC class molecules. This will lead to attracting T cells (CD4+ and CD8+). This chemokine activity is further enhanced by the presence of the adjuvant component to enhance immune response from the viral particle. The cascade of immune activation leads to immediate immune response to target the virus as well as creating memory B cells specific to the antigen that the virus have. These memory B cells enhances our immune response by faster immune cell recognition of these subsequent viral exposure to the same antigen compared to the initial exposure.

Manufacturing In February 2021, Novavax partnered with Takeda to manufacture the vaccine in Japan, where its COVID‑19 vaccine candidate is known as TAK-019. Novavax signed an agreement with Serum Institute of India for mass scale production for developing and low-income countries. In 2020 it was reported, that the vaccine would be manufactured in Spain and in November 2021 it was reported to be produced in Poland by Mabion SA, a Contract Development and Manufacturing Organisation (CDMO). As of 2021, antigens were made at Novavax's factory Novavax CZ in the Czech Republic; Novavax CZ was also marketing authorisation holder of its EU authorization. In May 2021, Serum Institute of India said that it started the production of the Novavax COVID‑19 vaccine candidate branded as Covovax in India after receiving permission from the Indian government.

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