Greece has started to distribute Covid-19 vaccines to migrant camps after criticism that authorities were taking too long to extend the programme.
Coronavirus shots will be offered to migrants living in camps on the islands of Lesbos, Chios and Samos from Thursday.
Migrants on the mainland and other Greek islands will be offered vaccines next week.
Greek migration official Manos Logothetis said the single-shot vaccine developed by Johnson & Johnson would be used.
Mr Logothetis said medical workers would be flown to the islands from Athens two days a week to carry out the injections.
The UN High Commission for Refugees says an estimated 9,400 people are living in camps on the northern Aegean islands.
Of these, more than 6,000 live in the main refugee camp on Lesbos, which was quickly rebuilt after a fire last year.
Mr Logothetis said only 15 per cent of asylum seekers in the country had expressed an interest in receiving the vaccine but he was confident this would improve.
"Considering that an estimated 30 per cent of this population is under 18 and another 30 per cent have already been infected, the road to asylum seekers' immunity … is short and we will succeed," he told the ANA news agency.
More than 5 million first shots have been administered across Greece but authorities were criticised for failing to deliver doses to camps.
Human Rights Monitor accused Greece of a "discriminatory" vaccine drive.
"Migrants living in refugee camps are more susceptible to Covid-19 than the general Greek population because of the overcrowding, the impossibility to keep social distancing, the lack of access to water, sanitation and hygiene facilities, and the restricted access to health care,” the organisation said.
Greece was also criticised for opening up to tourists but keeping the migrant camps in lockdown.
Meanwhile, the UK High Court ruled on Thursday that Napier Barracks in Kent, south-east England, fell "below the minimum standard" while housing hundreds of asylum seekers since last September.
The court said it was inevitable that there would be a major Covid-19 outbreak at the camp, where each dormitory is shared by 12 to 14 men.
That outbreak came in January.