ATAGI Statement – Response to NSW COVID-19 outbreak – 24th July 2021

A statement from the Australian Technical Advisory Group on Immunisation (ATAGI) in response to the NSW COVID-19 outbreak.

Date published:
General public


All individuals aged 18 years and above in greater Sydney, including adults under 60 years of age, should strongly consider getting vaccinated with any available vaccine including COVID-19 Vaccine AstraZeneca. This is on the basis of the increasing risk of COVID-19 and ongoing constraints of Comirnaty (Pfizer) supplies. In addition, people in areas where outbreaks are occurring can receive the second dose of the AstraZeneca vaccine 4 to 8 weeks after the first dose, rather than the usual 12 weeks, to bring forward optimal protection.


ATAGI continues to closely monitor the epidemiology of COVID-19 in New South Wales, Victoria and South Australia. The outbreak in NSW continues to grow and the risk of disease, particularly in the greater Sydney area, is likely to continue to be significant over coming weeks. 

ATAGI reaffirms our previous advice that in a large outbreak, the benefits of the COVID-19 Vaccine AstraZeneca are greater than the risk of rare side effects for all age groups.

In the context of the current risk of COVID-19 in NSW and with the ongoing constraints on Comirnaty (Pfizer) vaccine supplies, all adults in greater Sydney should strongly consider the benefits of earlier protection with COVID-19 Vaccine AstraZeneca rather than waiting for alternative vaccines

Maximal protection requires two doses of vaccine, but even a single dose of either vaccine provides substantial protection (by more than 70%) against hospitalisation. A single dose of COVID-19 Vaccine AstraZeneca partially reduces transmission by around half and therefore may also benefit close contacts and the community. It should be noted that there is a delay of 2-3 weeks after receiving a first dose of vaccine and being protected from COVID-19.

A second reason for ATAGI to recommend that individuals strongly consider vaccination at this time is emerging data about severity of disease. The Delta variant may be more severe than the original SARS-CoV-2 strain. The proportion of people less than 60 years requiring hospitalisation appears to be higher than was reported in outbreaks with the original SARS-CoV-2 strain. This reinforces the benefit of protection with any available vaccine.

People considering vaccination should be informed of the benefits and risks and give informed consent. People who receive COVID-19 Vaccine AstraZeneca should be aware of the symptoms of thrombosis with thrombocytopenia syndrome (TTS), and when to seek prompt medical attention. Early detection of TTS means that people can get treatment and this can improve their outcomes.

ATAGI has previously issued advice recommending a shorter interval between the first and second doses of COVID-19 Vaccine AstraZeneca of 4-8 weeks in an outbreak (versus the routine 12 week interval) so that maximal protection against COVID-19 can be achieved earlier.

ATAGI also reinforces that the interval between the first and second doses of Comirnaty (Pfizer) is 3-6 weeks, providing flexibility in managing available supplies of vaccines, whilst also noting two doses are required for optimal protection. Spacing Comirnaty (Pfizer) to a routine interval of 6 weeks would allow limited vaccine supplies to be redirected to obtain first dose protection in outbreak areas of greatest need.

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