Adults under the age of 60 who cannot access the Pfizer Covid-19 vaccine should be able to receive the AstraZeneca jab instead if they are in a Delta variant outbreak zone, health authorities say.
The Australian Technical Advisory Group on Immunisation said in a statement on Tuesday that its recommendations for non-outbreak settings were unchanged.
“In the context of a Covid-19 outbreak where the supply of Comirnaty (Pfizer) is constrained, adults younger than 60 years old, who do not have immediate access to Comirnaty (Pfizer), should reassess the benefits to them and their contacts from being vaccinated with Covid-19 vaccine AstraZeneca, versus the rare risk of a serious side effect,” ATAGI said.
While the recommended interval between the two doses of AstraZeneca was between four and 12 weeks, during outbreaks it should be between four and eight weeks, the group added.
“Therefore, people in an outbreak situation who received their first dose of Covid-19 vaccine AstraZeneca more than four weeks ago should contact their vaccine provider to arrange their second dose as soon as possible,” they said.
In non-outbreak situations, the preferred interval between doses of the AstraZeneca vaccine remains at 12 weeks.
Recommendations about the use of the Pfizer vaccine remain unchanged in all settings.
ATAGI said in outbreaks, such as the one in Sydney, the benefits of vaccination were greater.
The experts said the current cumulative risk of the virus for Sydney residents to July 11 was about 10 per 100,000 and was increasing by two more cases per 100,000 every day.
“Although overall this is comparable to the Australian first wave (cumulative incidence 29 per 100,000), the ongoing risk would be considerably greater in some parts of Sydney and for specific populations,” ATAGI said.
For example, it said the in Fairfield local government area, the cumulative risk was greater than 100 per 100,000 and had increased by more than 10 cases per 100,000 each day in the past week.
ATAGI reiterated that the benefits of the AstraZeneca vaccine strongly outweighed the risks of adverse effects in people over the age of 60.
The group said all people who received the AstraZeneca jab should be provided with information about common and rare, but serious, side effects including thrombocytopenia syndrome.
“They should be advised that if they experience any signs or symptoms consistent with TTS, they should seek immediate medical attention,” ATAGI said.
Additional unallocated supplies of the Pfizer and AstraZeneca vaccines should be prioritised to populations and areas of greatest risk, the experts added.