Vaccination and the new COVID variants – will it work?

Seniors are near the top of the national vaccination queue but the UK, Brazilian and South African variants of the virus are raising questions about the effectiveness.

Key Points

  • Scientists are optimistic current vaccinations will be effective against variants
  • The level of effectiveness is in question
  • Best way to stop mutation is to vaccinate and stop the spread of COVID

There’s evidence the current vaccinations work against the variants but researchers caution the level of effectiveness is not fully known and will probably need ‘tweaking’ in the future.

The vaccine technology can be adapted to emerging viral variants but the Director of Infectious Diseases and Immunology at Menzies Health, Professor Nigel McMillan told ABC News that "Our best vaccine is probably always the next one."

"While this isn't going to be a virus that mutates and changes as quickly as influenza, it certainly will change. "The virus has upped its game, and so must we."

The virus variants, reported to be more contagious, were discovered in the UK, South Africa and Brazil in recent months, and while it is accepted that viruses evolve and change, researchers are surprised that variants could impact on vaccine effectiveness so soon.

Pfizer has reported its vaccine, which has been approved for use in Australia, appears to be just as effective against the UK variant as earlier versions of the virus.

Similar results were reported by Moderna, which also makes an mRNA COVID-19 vaccine.

However, it has been reported that both companies have found their vaccines appear to slightly less effective against the South Africa variant, but still produced enough antibodies to be protective.

"The virus has upped its game, and so must we."

Results from phase 3 trials of the Novavax vaccine, which the Australian Government has also committed to purchasing, found the vaccine was 90% effective against the original SARS-CoV-2 strain, 85% effective against the UK variant, but only about 50% effective against the South African one.

Even though that appears to be a big drop, anything over 50 is regarded as acceptable.

Another study of blood samples of infected people in South Africa found almost half had no detectable antibodies to the new variant. Researchers are investigating whether this means people could get reinfected.

Similarly, while there is very limited data on the variant in Brazil, it's linked to a spike of infections in a city where it was thought a majority of people had already been infected.

While the findings warrant concern (and further investigation), it's important to remember that vaccines generate much more robust immune responses than natural infection, and that neutralising antibodies are just one component of our immune defence.

Stuart Turville, an associate professor of immunovirology at the Kirby Institute said it was reassuring none of the variants had been shown to completely evade vaccine-induced antibodies, so far.

"If we were talking about a variant of concern that was completely refractory to the vaccine response, then we'd be having another conversation," he told ABC News.

"The fact we're seeing positive responses … I think it's still good news."

What if vaccines don't stop the disease?

The aim is to reduce the number of people with the virus and slow down its spread. The vaccines will do that, to what degree has yet to be seen.

However, fewer sick people spreading the disease means easing the burden on healthcare systems and contact tracing teams.

Even if vaccines only reduce severe disease, they are still expected to have a significant effect on transmission.

Professor McMillan believes we'll have to live with the coronavirus, like other viruses.

"We vaccinate people and we prevent death and we just kind of go back to normal, but the virus circulates around — people get it, but we don't think about," Professor McMillan said.

"It's kind of like the flu in a sense. You'll have a few people die from the flu, lots of people might get the flu … but people aren't dying needlessly from it."

Priority now

Epidemiologist Professor Terry Nolan said the priority was getting people vaccinated — in Australia and around the world and reduce opportunities for the virus to mutate further.

"The more virus that's circulating, the more risk there is for everyone," he said.

"So whatever we do, both in terms of public health measures and vaccines, stamping out the virus is still the best way to control the mutants."