Drop-in MMR clinics are being held at four hospitals in Swansea and Neath Port Talbot, as the death of man linked to the measles outbreak is investigated.
Gareth Williams, 25, died at his home in Swansea on Thursday.
Tests by Public Health Wales have confirmed that he had measles at the time of his death.
The number of reported measles cases in Wales now stands at 808.
It is the third weekend in a row that vaccination clinics have been held, in a bid to stem the epidemic.
Pupils at five schools have also been offered MMR jabs, with a further 10 schools being visited by vaccination teams in the coming week.
The appeal by PHW for parents to make sure their children are vaccinated against measles has taken an increasingly urgent tone, following the death of Mr Williams at his home in Port Tennant Road in Swansea.
Tests on Friday confirmed that Mr Williams did have the disease when he died, though further investigations are under way to establish if the illness is linked to the death.
“Whatever the cause of death in this case we should not be surprised if, as the outbreak grows, we start to see deaths in Wales,” said Dr Marion Lyons, PHW’s director of health protection.
‘At-risk’ age groups
“Those not fully vaccinated with two doses of MMR are highly likely to catch measles, which is highly contagious.
“We know that there are unprotected people in all age groups but we have particular concerns about the 10 to 18 age group.
“We are therefore urging all parents of children who have missed doses of MMR to arrange vaccination for them as a matter of urgency.”
Since the outbreak began in November, 77 people have needed hospital treatment for the illness.
New vaccination clinics are being held on Saturday at Morriston and Singleton Hospitals in Swansea, the Princess of Wales Hospital in Bridgend and Neath Port Talbot Hospital.
Last weekend around 2,500 people received the MMR vaccination at special clinics in south Wales.
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