Pfizer’s bivalent COVID vaccine has been approved for use as the next big boost to Australian immunity.
Federal Minister for Health and Aged Care, Mr Mark Butler, announced on 15 November 2022 that the Australian Government has accepted a recommendation from ATAGI on the use of the Pfizer Comirnaty Bivalent Original/Omicron BA.1 vaccine (tozinameran and riltozinameran) as a third and fourth dose in people aged 18 years and older.
ATAGI found the next generation vaccine triggered a modest improvement in the immune response against both strains, and that both this vaccine and the original version provided significant protection from severe disease against Omicron subvariant infections.
“The Australian Government has added this next generation Pfizer vaccine to our armour against COVID,” Minister Butler said.
“This is a reminder to all Australian to make sure you are up to date with your COVID vaccinations, now is the time to get your booster.”
Following the Government’s announcement, ATAGI has updated its existing recommendations regarding the use of bivalent Original/Omicron BA.1 vaccines to include:
- The Pfizer bivalent vaccine can be used as an alternative vaccine to any of the available mRNA COVID-19 vaccines (Pfizer original vaccine, Moderna bivalent vaccine or Moderna original vaccine) for any booster dose in people aged 18 years or older who are currently recommended to receive a COVID-19 booster.
- In those who are eligible for a booster dose, ATAGI does not have a preference for bivalent mRNA vaccines over original mRNA vaccines.
- Booster doses of COVID-19 vaccine should be given at least 3 months after the most recent COVID-19 vaccine dose or confirmed SARS-CoV-2 infection.
- As with other mRNA COVID-19 vaccines, the Pfizer bivalent vaccine can be co-administered with other non-COVID-19 vaccines.
- The Pfizer bivalent vaccine is not recommended for the primary course of vaccination (the first two doses in most people or first three doses in severely immunocompromised people).
- ATAGI does not currently recommend use of the Pfizer bivalent vaccine as a booster in anyone aged under 18 years as it is not registered for use in this age group.
The first doses have already arrived in the country and are undergoing continued batch testing by the Therapeutic Goods Administration (TGA), with the rollout of the bivalent vaccine set to commence from 12 December 2022.
Even though clinical studies assessing the activity of this vaccine against the BA.4/5 subvariants are ongoing, initial results demonstrate that the vaccine produces neutralising antibodies against BA.4/5, though to a lesser extent than BA.1, and the TGA provisionally approved the bivalent vaccine for use as a booster dose in adults 18 years and over on 27 October 2022.
In making this regulatory decision, the TGA said that it carefully considered data from an ongoing clinical study, which showed that using the bivalent vaccine as a booster dose elicited a superior neutralising antibody response against Omicron BA.1 strain – and a similar response against the ancestral strain – when compared to the original COMIRNATY vaccine.
This is the second bivalent vaccine approved for use in Australia, with Moderna’s Spikevax Bivalent Original/Omicron BA.1 vaccine available to people aged 18 years or older since 14 October 2022.
A separate recommendation from ATAGI to make the paediatric Pfizer COVID vaccine available for certain at-risk children aged 6 months to under 5 years has also been accepted, and this vaccine will also become available for eligible children from mid-January 2023.
However, this paediatric vaccine is being restricted to children who are severely immunocompromised or who have other specific conditions that put them at increased risk of severe illness.