At the headquarters of biotechnology company Novavax, scientists are developing what they hope could soon be another Covid-19 vaccine for the United States.
Data from the company’s large-scale Phase 3 clinical trial of the vaccine i n the US and Mexico are expected this month, but the timeline depends on how quickly it accumulates data on the prevalence of disease in trial areas. The company’s vaccine against Covid-19 has been a year in the making, Dr. Gregory Glenn, president of research and development for Novavax, told CNN. The work began even before the world realized it faced a pandemic. In January of last year, Glenn and his colleagues were closely watching an unusual cluster of pneumonia reported in China. They wondered whether that outbreak could be due to another version or recurrence of the coronavirus that causes severe acute respiratory syndrome or SARS. « It occurred to us that this just might be ‘SARS 2,’ » Glenn said. « The sequence was published on the Internet, the genetic sequence for the virus — and we could see it was a coronavirus. Then we kicked into action. » How Novavax’s vaccine works — using moth cells When the sequence published online, scientists around the world quickly identified the SARS-CoV-2 virus, which causes Covid-19, as a coronavirus because it has what are called « spike proteins » on its surface. These spikes form large protrusions, giving coronaviruses the appearance of wearing crowns. Corona is the Latin word for « crown. » These knob-shaped structures are what the virus uses to connect to human cells, causing infection. Getting the immune system to recognize and « remember » those spike proteins is key in how a vaccine helps protect against Covid-19. Yet the way various coronavirus vaccines do that can vary. Novavax’s coronavirus vaccine, called NVX-CoV2373, differs from the three vaccines already being distributed in the United States. The vaccine relies on what is called recombinant nanoparticle technology and Novavax’s adjuvant, called Matrix-M, to stimulate an immune response and stimulate high levels of neutralizing antibodies. When the genetic sequence for the coronavirus was published, Novavax scientists identified the gene for the spike protein and created a modified version of that gene. The researchers cloned the genes into a baculovirus that infects insects. They then infected moth cells — specifically, cells from the fall armyworm insect — with that virus, prompting them to produce the coronavirus spike protein. These virus-like nanoparticles were harvested to make Novavax’s vaccine. « The whole idea of the vaccine is to show the immune system something that looks, tastes and acts like a virus, with the exception that it doesn’t make you sick. So we made the spike protein. We put it in a particle — basically, like a soap bubble — and it’s the size of the virus, » Glenn said. « It’s not infectious. We never touch the coronavirus itself, » he added. « Then that is given to people, and they make an immune response that’s very much focused just on the spike — and I would say, the hallmark of our vaccine is it gives a very strong immune response with very few side effects, and the dose is very small and the vaccine can be stored with normal refrigerated temperatures.
