'I'm shaking my head': Expert cautions against mixing vaccines
Key Points
- NSW reports four local cases, three linked to Berala cluster. See the full list of exposure sites here.
- Victoria has reported three local COVID-19 cases. See the full list of exposure sites here.
- England, Scotland enter an immediate full shutdown in the face of spiralling infections.
- Victoria wants international flight crews to be quarantined after eight cases in two weeks.
'I'm shaking my head': Immunologist cautions against mixing vaccines
One immunology expert has thrown cold water on the idea of mixing and matching vaccines, or delaying the second dose in order to stretch supplies.
The COVID-19 vaccines produced by Pfizer, AstraZeneca and Moderna all require two doses of vaccine given several weeks apart, a dosing regimen known as "prime-boost". The first shot primes the immune system to recognise the virus, while the second shot boosts the response to the virus.
The UK has ordered doctors to delay the second dose of its vaccines for up to three months in order to inoculate more people, despite the fact that the vaccine makers only tested the shots on a schedule of two doses given several weeks apart.
Other European countries are also considering delaying the second dose but top experts in the US have opposed the move, saying the vaccines should be given on the manufacturers' schedule.
Britain has also said that in some cases doctors could mix and match vaccines, giving people a second dose of a different vaccine.
Immunologist Professor Magdalena Plebanski from RMIT told the ABC it was possible that delaying the second dose or mixing vaccines could ultimately prove to be a better strategy for fighting COVID-19. But there was presently no data to show for it.
"It could give an even better response, we don't know - but it could be a worse response. At this point we don't have the scope to be guessing wrongly," she said. "So it's very, very important to adhere to the schedule that has been proven to give an effective immune response."
Asked for her response to the idea of mixing vaccines, she replied: "I'm shaking my head here. They're not interchangeable, the vaccines, and the doses give different immune responses. This should not be played with, not just because of efficacy but also for safety. It is possible that combinations of vaccines may work together brilliantly, you know, in a prime-boost scenario.
"But this has not been tested. The safety of those prime-boost combinations has not been tested. So it really is something that should not be done."
Latest In Federal
Fetching latest articles