Pfizer, AstraZeneca, Moderna. Britons have become so accustomed to the three Covid vaccines available in the UK that most have forgotten about another jab, Novavax – even though the government has ordered 60m doses and hundreds of British jobs depend on it.
“`Late last month the US company, with a factory on Teesside primed to manufacture doses, submitted final data to UK regulators and a positive decision is anticipated within days or weeks. It will bring to an end what feels like a long wait compared with the speedy development and approval of the other jabs, including for those who took part in trials.
So what difference would this additional weapon make to the UK’s vaccination armoury? Novavax’s offering is a protein-based jab – similar to those used to protect against flu, and for routine childhood vaccination against pertussis (whooping cough) or meningococcal infection.
Other protein-based Covid vaccines are also in late-stage clinical trials, including one being developed by Sanofi and GSK, again with 60m orders from the UK. Final data from its phase 3 trial is expected any day now, paving the way for the companies to seek regulatory approval.
Whereas existing UK Covid-19 jabs instruct our cells to manufacture the coronavirus spike protein, protein-based vaccines deliver pre-made fragments of it alongside an immune-stimulating adjuvant.
Clinical trials suggest that two doses of the Novavax jab have an efficacy of about 90% against symptomatic Covid – similar to the other approved UK vaccines. It is also undergoing “mix and match” testing with the Oxford/AstraZeneca or Pfizer/BioNTech jabs and preliminary data suggest it generates a robust immune response when given as the second dose.
But it is the emerging signs of reduced side-effects that could make Novavax particularly attractive.
Trial data appear to show the potential for lower “reactogenicity” compared with existing jabs, meaning side-effects such as injection-site swelling, fatigue, headaches and muscle pain occur less frequently. No direct head-to-head comparisons have yet been done, however, and further studies are needed.
“Lower reactogenicity becomes particularly important in groups such as children, where the balance between vaccination and not vaccination becomes a little less clear, simply because, for example, in young children the likelihood of them having severe Covid-19 is so small,” said Prof Paul Heath, the director of the Vaccine Institute at St George’s, University of London, and chief investigator of Novavax’s UK trial.
However, a caveat with any new vaccine is that rarer side-effects may not become apparent until a vaccine is used widely, said Azeem Majeed, professor of primary care and public health at Imperial College London. “Post-marketing surveillance would be needed to identify any previously unknown side-effects,” he said.“`