How effective is the Novavax vaccine?
Novavax said on Monday that its two-shot Covid-19 vaccine was 90 per cent effective at preventing symptomatic cases and 100 per cent effective at preventing moderate and severe symptoms.
The US-based biotech firm said it was also 93 per cent effective against variants of concern such as the Alpha strain that originated in the UK.
Findings on its efficacy were based on trials involving nearly 30,000 people in the US and Mexico who were injected at random with either the Novavax vaccine or a placebo.
The study produced 77 cases of the virus. Of these, 14 people had received the vaccine and 63 the placebo.
The infections were all mild but with only one case of the highly infectious Delta strain among these 77 infections, the vaccine's efficacy against the most concerning of all variants is not assured.
How is the Novavax vaccine made?
The Novavax vaccine uses a traditional method to train the immune system to make antibodies to Covid’s spike proteins.
It differs from mRNA vaccines like Pfizer and Moderna that use genetic code to create an immune response.
Researchers began by modifying the spike gene, which was inserted into a virus called baculovirus and allowed to infect moth cells. The infected cells produced the spikes seen on the SARS-CoV-2 virus, which were then harvested and assembled into nanoparticles. These nanoparticles mimic Covid’s molecular structure but do not cause it.
Immune cells, with the assistance of helper T cells, then take on the spike proteins and tear them apart.
B cells can encounter the vaccine nanoparticles and if they are congruously shaped, will latch on to the spike protein and proliferate, producing antibodies of the same shape.
The production of these correctly shaped antibodies is what stops coronavirus from entering the body's cells.
The same method is used to make vaccines for flu and HPV.
When will the Novavax vaccine be circulated?
The company, whose headquarters are in the US state of Maryland, says it will file for regulatory approval in the third quarter of this year, a little later than planned due to some manufacturing gremlins.
It is on track to reach a manufacturing capacity of 100 million doses a month by the end of September and 150 million by the end of 2021.
Which countries have ordered the Novavax vaccine?
Six countries had ordered the Novavax vaccine as of March this year.
By far the biggest order was placed by India (100 million doses).
The US (100 million) is next, followed by the UK (60 million), Canada (52 million), Australia (51 million) and China (50 million).
High levels of supply in India will be facilitated by the country’s Serum Institute, which is one of the vaccine’s approved producers.
In the UK, production will take place at the Fujifilm plant in the north-east of England. The final stage of manufacturing will then take place at GlaxoSmithKline's plant in Barnard Castle – of Dominic Cummings fame.
Novavax has agreed to supply 1.1 billion doses to the Covax initiative, which secures vaccines for low and middle-income countries.