US-based biotechnology company Novavax's COVID-19 vaccine prepared using the spike protein of SARS-CoV-2, exhibited a 90.4 per cent efficacy against the virus. This result was observed among over 29,960 participants across 119 sites in the US and Mexico. Its efficacy has also been tested in UK and South Africa.
This vaccine uses the genes encoded in the spike protein of SARS-CoV-2, transfers it to a moth cell, and then inserts the non-SARS-CoV-2 containing spike protein expressed by the moth cell into nanoparticles. These nanoparticles are then injected in the body to elicit antibodies.
Novavax has chosen Serum Institute of India to manufacture close to two billion doses of the vaccine for India as well as other low- and middle-income countries. The Indian vaccine manufacturer has already completed the technology transfer and has initiated bridging trials to understand the effectiveness of the vaccine in India.
In its earlier trials held in UK, the NVX-CoV2373 vaccine was tested against the variants of the original virus. While the vaccine showed 96 per cent effectiveness against the original virus, its efficacy dropped to 86.3% against the B.1.1.7 (Alpha) variant and was 89.7% overall. Against the B.1.351 strain predominant in South Africa, the vaccine's efficacy was only 48.6 per cent.
How Does This Vaccine Work?
This NVX-CoV2373 uses a different technology to prepare the vaccine which has been used earlier in the HPV vaccine against hepatitis. None of the currently in use COVID-19 vaccines, use the recombinant nanoparticle- protein technology used by Novavax. Novavax mixes the genes of the spike protein with its specially created nanoparticles in the vaccine. This nanoparticle studded with spike proteins do not contain the virus and do not replicate or cause COVID-19.
The already approved vaccines either use m-RNA technology (Moderna, Pfizer), use other viruses as vector viruses (Oxford-AstraZeneca, Sputnik V, Johnson and Johnson), or use the inactivated original strain (Covaxin).
Efficacy Results In The US
There were no cases of severe adverse events among participants who received the Novavax vaccine. From the 29,960, only seventy-seven people were infected with COVID-19. Sixty-three of these cases were observed in the placebo group while fourteen were in the ones who received the vaccine.
They even sequenced 54 of the 77 samples to find the efficacy of the vaccine against the variants of concern and variants of interest. Thirty-five of these 54 sequences were found to be one of the four variants of concern.
The biotechnological company has recruited close to 2,284 children between the ages of 12-18 to test the vaccine in the group.
Storage and Dosage
The vaccine is easy to store as it requires to be stored at 2-8ºC and thus it can be stored in the refrigerator at normal cooling temperatures. It is packaged in a ready-to-use liquid formulation in ten-dose vials.
The vaccine is to be given in two doses within a duration of 21 days as decided by the researchers.
Novavax is still to test the duration for which the vaccination provides immunity against SARS-CoV-2 and its variants.
