CANBERRA, Australia — Australia’s prime minister says he’s urging the government’s adviser on vaccines to change its advice against adults under age 60 taking the AstraZeneca shot.

More than half the nation is locked down because of growing COVID-19 clusters.

The Australian Technical Advisory Group on Immunization last month lifted the minimum recommended age for taking AstraZeneca from 50 to 60 because of the greater risk of rare blood clots associated with the vaccine in younger people.

The change followed the death in Australia of a 52-year-old. Prime Minister Scott Morrison said he was appealing to ATAGI to change its age advice due to the escalating risk from the more contagious delta variant. The only alternative to AstraZeneca in Australia is Pfizer which is in short supply.