Regulators in Australia and the United States last week of August 2022 approved Omicron-specific boosters, following approval in the United Kingdom in mid-August.
In Australia, a Moderna Omicron booster has been provisionally approved for use in adults aged 18 and over. Supplies are expected to arrive in the coming weeks, however the Australian Technical Advisory Group on Immunisation (ATAGI) is yet to advise the government on how the vaccine will be used.
So what’s new about the Omicron booster? And what sorts of advances in vaccine technology might we see next?
Why do we need new vaccines?
The current COVID vaccines will go down in history as one of the greatest achievements of medical science. Developed at record pace – without omitting any of the usual steps to ensure safety and efficacy – the vaccines significantly decreased the risk of severe disease and death.
But they’re less effective at reducing infection. Frequent boosters have been required to protect against new sub-variants. This is because the spike protein, which the vaccines target, has changed. And over time, our protection has reduced due to waning immunity.
What are the Omicron-specific vaccines?
Most manufacturers of approved COVID vaccines began making boosters targeting previous variants as far back as Alpha. But until Omicron, these variant-specific boosters offered no significant advantage over vaccines targeting the original, or Wuhan, strain.
The new Omicron boosters combine two different targets in the one vaccine, known as a bivalent vaccine. This provides broader cross-protection – against the currently circulating variants but possibly against future variants too.
The first of these boosters, manufactured by Moderna, targets the BA.1 Omicron sub-variant in addition to the original or Wuhan strain. It also provides some protection against BA.4 and BA.5. This is now approved in the UK, Australia and US.
The US has also approved the Pfizer bivalent booster, which targets the spike of BA.4/BA.5 as well as the original strain.
What vaccine technology might we see next? Scientists are working to develop COVID vaccines that:
Offer longer lasting protection.
Protect against new variants and sub-variants.
Provide similar levels of protection from a single dose.
Don’t require freezing or refrigeration, and that have an extended shelf life.
Deliver a strong response from lower doses of active ingredient.
[Paul Griffin is affiliated with The University of Queensland, Nucleus network and Mater research where he has been the principal investigator on 8 COVID-19 vaccine studies and also serves on the advisory boards of AstraZeneca, MSD, Pfizer (covid therapy) and GSK and has received speaker honoraria from AstraZeneca, Seqirus, Novartis and Gilead.]