Rome, Sep 21 : Italy has started administering the third dose of a Covid-19 vaccine, after the booster shots received the official green light from the country's Medicines Agency (AIFA). As the Health Ministry announced earlier this month, third doses of either Pfizer-BioNTech or Moderna vaccines will be offered to people with fragile immune systems, reports Xinhua news agency. This includes not only immuno-compromised people, but also elderly people and residents in care homes. Based on guidelines issued by AIFA, healthcare workers will also receive the booster shot. The third dose will be offered as an option, since vaccination against coronavirus is strongly recommended but not mandatory in Italy. AIFA has recommended that the third shot should be available at least 28 days after the previous dose for immuno-compromised people. For those over 80, people living in care homes, and healthcare professionals, the third dose would be considered as a "booster to maintain an effective immune response", and should be administered at least 6 months after their last dose. Overall, AIFA and the Health Ministry have stressed that the national priority should remain to ensure that a majority of the population is vaccinated. Till date, some 76 per cent of the target population (those aged over 12) has been fully immunised, while 82 per cent have received at least one dose, according to data from the Health Ministry. Since the pandemic broke out in Italy in February 2020, the country has registered 4,638,516 confirmed coronavirus cases, with 130,354 fatalities and 4.4 million recoveries. /IANS