Secondary school children rolled up their sleeves on Friday to receive the MMR jab in one of the areas worst affected by the measles outbreak.
Around 70 children, more than 10% of the pupils at All Saints School in Ingleby Barwick, Teesside, received the jab in the dinner hall after their parents consented.
Professor Peter Kelly, chairman of the Tees Outbreak Control Team, said there were 186 confirmed cases on Teesside since the new year, with a similar number suspected.
"It's quite a serious problem on Teesside," he said. "We have been aware of it since it started in mid-January and we have been working with our GP colleagues.
"We wrote to parents six or seven weeks ago to advise them to take their children, if they weren't vaccinated, to the GPs.
"We felt the extra step of coming to schools would give us that really comprehensive coverage of children we need to catch.
"There is a myth that it is just a childhood illness. People can be very poorly with measles and there can be some very serious complications."
Lucy Butler, 15, from Ingleby Barwick, had the jab.
"I sat down and they wiped my arm to make sure it was clean," she said. "They injected me and it was just a small scratch, I didn't really feel anything.
"I was scared at the start but it was fine.
"I was quite worried about the outbreak, that's why I got the vaccination.
"I wouldn't want to be ill during my exams."
Headteacher Kevin Mann said: "We are coming up to important GCSE exams time and the last thing we need is for a student who's going to get good results put out of action by measles.
"It's important for their future."
He said parents should think of the consequences of not having their children vaccinated.
"I think measles getting loose in the population where there is a significant proportion of children who aren't vaccinated potentially carries a risk for a much wider community.
"The children here have friends at other local schools and if measles was abroad in our school it would very quickly pass on to the wider community."