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Australia; VIC; QLD
Media release
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Expert Reaction
These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.
Dr Roger Lord is a senior lecturer (Medical Sciences) with the Faculty of Health Sciences at The Australian Catholic University and Visiting Research Fellow with The Prince Charles Hospital (Brisbane)
The risk of serious illness and hospitalisation following the Sydney outbreak of the Delta variant of COVID-19 is significant.
Vaccination with the Pfizer COVID-19 vaccine is preferred for individuals under the age of 60 years.
Where this is not available, careful consideration in consultation with a general practitioner should be given to having the AstraZeneca (AZ) COVID-19 vaccine.
The risk of contracting the Delta strain of COVID-19 and suffering serious illness in an outbreak situation is far greater than the risk associated with a possible adverse effect from the AZ vaccine.
Receiving the first vaccination of AZ will provide some protection in 7-10 days against the virus and is better than no vaccination at all.
The AZ vaccine is more effective if the second dose is given and after a longer period of time from the initial vaccination.
AZ was found to be 55 per cent effective in those who received their second dose less than six weeks after their first vaccination compared to 81 per cent if the second dose is given more than 12 weeks after the initial vaccination (M. Voysey et al. Lancet https://doi.org/fwk7; 2021).
Reducing the time for the second vaccination will therefore reduce overall effectiveness but still be important in the reduction of serious illness caused by the Delta strain of the virus.
This is of particular importance to those living in Sydney where a significant outbreak has occurred.
Subsequent booster vaccinations can be given at a later time to increase effectiveness lost by having the second AZ vaccination earlier.
Prof Bruce Thompson is the Head of the Melbourne School of Health Sciences at The University of Melbourne
The overarching message is that the AstraZeneca vaccine is a safe vaccine, that has been approved by the TGA [Therapeutic Goods Administration] for the purposes of vaccinating against the SARS-COV2 virus. The concept of recommendation for certain populations is quite a different concept, and these recommendations can change as we have seen. It doesn’t mean that the vaccine is not safe, or is what we call a contraindication.
What will the shorter turnaround on the second shot of AZ do to its effectiveness?
There is a window in which the second shot can be given and still be effective. The time frame they are suggesting is within that window.
How should young people interpret the direction to ‘re-assess’ taking AZ?
As there are more and more cases of COVID-19 appearing in the Sydney area, the risk of contracting the virus is therefore higher. We know in the current outbreak that 10 per cent of active cases are now in hospital with an escalating pneumonia-like illness. Approximately three per cent are in the ICU, of which one is a teenager. This is a series medical condition, and as the risk of contracting the virus has increased, it is time to rethink early vaccination.
How useful is it to change vaccine behaviours in response to an outbreak rather than pre-emptively?
Ultimately the main thing is get everyone vaccinated a quickly as possible.
Should people outside Sydney be considering following this new advice right now?
Yes I would!
