Italy said Saturday it would restrict the AstraZeneca vaccine to the over-60s, with younger people who have already received one dose to complete the cycle with an mRNA jab.
The change follows an improvement in coronavirus infection rates in Italy, which has been devastated by the pandemic but will next week lift restrictions in much of the country following a sharp decline in cases.
The EU's medicine agency in April drew a link between rare blood clots and AstraZeneca jabs but stressed that the benefits of the vaccines outweighed the risks.
Malta is currently administering the AstraZeneca vaccine to anyone aged 18 to 70, in line with recommendations made by the European Medicines Authority.
The Italian government's Technical and Scientific Committee (CTS) said that "the changed epidemiological situation has led to a reassessment of the risk-benefit ratio for age groups less at risk of severe forms of COVID-19."
A health ministry statement Saturday updating the CTS opinion on vaccines said that AstraZeneca's vaccine should now be given "only to people aged 60 or over".
Out of a principle of "maximum caution", for the under-60s who have already received the first dose of AstraZeneca, "the cycle should be completed with a second dose of mRNA vaccine" such as Pfizer-BioNTech or Moderna, administered eight to 12 weeks later.
Italy in March blocked the AstraZeneca jab over health fears, but after the EU's medicines agency gave the green light, approved it for everyone over 18.
It recommended preferential use for people over the age of 60, but AstraZeneca has been used for younger people, including in popular "open days".
Italy has so far administered 41 million vaccines and almost 14 million people out a population of around 60 million are fully vaccinated.
From Monday, restrictions in regions home to more than 40 million people, including the areas around Milan and Rome, will be classified as the lowest risk "white" zones.
Most coronavirus restrictions will be eased except for the requirement to wear a mask and respect social distancing.
Health Minister Roberto Speranza said it was an "encouraging result that allows us to look forward with more confidence", while urging people to remain vigilant.
About 127,000 people with coronavirus have died in Italy since February 2020.