Another Covid-19 vaccine, this one from the biotech firm Novavax, has posted superb results in a phase 3 clinical trial, the company announced on Monday. But with more than half of US adults now vaccinated against Covid-19, the biggest impact of these results may be in other countries.
The Novavax vaccine stands out from other Covid-19 vaccines because it uses a technology that has not been deployed to date. It can also be stored at ordinary refrigerator temperatures, unlike some other vaccines that have strict freezer requirements that complicate distribution.
Novavax said its vaccine candidate was 90 percent effective overall against Covid-19 cases that produce symptoms, and 100 percent effective against moderate and severe disease. The results, from nearly 30,000 participants across the US and Mexico, could make it the fourth Covid-19 vaccine to begin distribution in the US, following vaccines developed by Pfizer/BioNTech, Moderna, and Johnson & Johnson.
But the first approvals of the vaccine will likely come in other countries, Stanley Erck, CEO of the Maryland-based company, told the New York Times. Novavax may not even seek emergency authorization for its vaccine in the US until September. At that point, it may not make much of a difference to the US vaccination effort.
As part of the US government’s Operation Warp Speed, last July Novavax was awarded $1.6 billion for vaccine development and production of 100 million doses. At the time, the 20-year-old company faced skepticism for never having brought a vaccine to market.
Novavax now aims to scale up production, with a goal of 150 million doses per month by the end of the year with factories in the US, South Korea, and India. Its two-dose vaccine comes at an expected cost of $16 per injection. That’s more expensive than the adenovirus-based vaccines developed by Johnson & Johnson and AstraZeneca, but around the same price or cheaper than the mRNA vaccines made by Pfizer/BioNTech and Moderna.
The Novavax vaccine did exhibit lower efficacy against variants of Covid-19, but the company is studying reformulated versions to target them. With Covid-19 continuing to spread in many parts of the world, having another option to counter the disease will bolster the effort to contain the pandemic.
What makes Novavax’s approach different from other Covid-19 vaccines
Vaccines are like target practice for the immune system: They encourage our bodies to build up defenses against a particular threat, without making us sick. When the real pathogen arrives, immune cells are ready to act, preventing infection altogether or dampening the worse effects of the disease.
Traditional vaccines contain weakened or inactivated versions of viruses or bacteria, or fragments of them. But new approaches have been brought to bear on Covid-19. Moderna and Pfizer/BioNTech vaccines use a snippet of genetic material, mRNA, encased in a nanoparticle. Human cells can read those genetic instructions and manufacture a fragment of SARS-CoV-2, the virus that causes Covid-19, which spurs the immune system to prepare for the virus.
The Covid-19 vaccines developed by AstraZeneca and Johnson & Johnson also shuttle genetic instructions to human cells, encouraging them to make a fragment of SARS-CoV-2, but they use a different virus — an adenovirus — that carries a snippet of DNA.
Novavax’s approach blends old and new techniques. To make the vaccine, the company combines another kind of virus — a baculovirus — with the genetic information needed to make a spike protein, a key fragment of SARS-CoV-2. When moth cells are infected with this virus, they manufacture the spike protein. Scientists then harvest and fuse those proteins with a nanoparticle. These nanoparticles combined with spike proteins are what is injected in the Novavax vaccine.
According to Novavax, this approach yields a strong immune response with minimal side effects. The main complaints from vaccine recipients were fatigue, headache, and muscle pain lasting less than two days.
How Novavax fits into the vaccination campaign
While new infections, hospitalizations, and deaths are trending downward in the United States, the Covid-19 pandemic continues to rage in other countries. India, currently an epicenter of the pandemic, recently set a new world record of more than 6,000 daily Covid-19 deaths. Part of the toll stems from the Delta/B.1.617 variant of the virus, which appears to be more transmissible. Health officials warn that other countries with limited resources and low vaccination rates remain vulnerable to their own outbreaks. And as long as the virus continues to spread, it risks mutating in dangerous ways that can reverberate to places like the US.
Leaders at the G7 summit last week committed to sharing 1 billion doses of Covid-19 vaccines with other countries, with half coming from the US. For its part, Novavax is partnering with manufacturers in other countries like India and South Korea to scale up its production. The company had pledged at least 1.1. billion doses of its vaccine through Gavi, an international vaccination consortium.
Novavax may still have a future role in the US. The company is investigating how its vaccine could work as a booster, bolstering protection from other vaccines as immunity wanes over time. A study last month showed that even mixing shots of different vaccine platforms led to robust immune protection. But it’s not clear yet how long the shielding provided by other Covid-19 vaccines will last.
At the same time, the virus itself is continuing to change. Novavax’s results on Monday showed that its vaccine had 86.3 percent efficacy at preventing disease caused by the Alpha/B.1.1.7 variant of the virus, which first appeared in the United Kingdom. It shows that protection was high, but not as high as immunity to earlier strains of the virus.
Early phase 2b results from South Africa, however, showed the vaccine yielded 48.6 percent efficacy against the Beta/B.1.351 variant in HIV-negative participants. The company is now investigating a retooled version of its vaccine aimed specifically at the Beta variant.
The ongoing evolution and spread of Covid-19 shows that the pandemic is not over, and it’s too early to become complacent. A new way to immunize against Covid-19 is a welcome development — particularly if it can reach the most vulnerable, and quickly.
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