New Zealand has been praised for eliminating cases of measles or rubella originating within the country over a three-year period.
Although the country's vaccination rates drew praise from the World Health Organisation, officials warned people not to be complacent.
Measles cases are still being brought into the country, prompting fears that people who are not immunised could be at risk of catching it.
New Zealand is one of just seven countries to have officially wiped out home-grown cases of measles and rubella, according to the World Health Organisation.
However, the Health Ministry's director of public health, Caroline McElnay, warned the country wasn't out of the woods just yet.
"It does meant that we can get cases that come into the country from overseas but we've got sufficient immunisation coverage that the disease won't take hold and become sustained."
For immunisation from measles, rubella and mumps two doses of the vaccine called MMR are needed.
Dr McElnay said among New Zealand's children and infants, 95 percent had had the first dose and 90 percent the full vaccine.
There had been 14 cases of measles this year coming into the country.
Dr Caroline McElnay said the disease had not been able to spread from those cases because New Zealand's immunisation coverage was high enough to stop it.
There was one group that was vulnerable, however.
"Teenagers and young adults. So that's the group that would have received measles vaccine before our national immunisation register was started.
"Since that was started we know that we've got really good immunisation rates. So that's a group that we've got less information about. We believe that the rates were lower then.
"What we want to do is increase immunisation in that age group."
The Ministry of Health held a symposium today discussing how to boost immunisation levels among teenagers and young adults.
Robert Hall is an official at the World Health Organisation and was there to talk to some of New Zealand's medical professionals.
"New Zealand has just gone through a process. They've applied for recognition by the World Health Organisation that the country is measles free and that process has gone through.
"The independent verification commission has determined that New Zealand has essentially eliminated indigenous measles from the country."
Dr Hall had a message for those who didn't believe in the need for vaccinations.
As a young doctor, he treated a child who wasn't vaccinated and contracted measles that led to a rare and chronic disorder of the central nervous system.
"And I can tell you, you don't want any child to go through that. That was a result of not being vaccinated, getting the disease and then getting one of the, admittedly rare, complications of disease.
"Measles is a serious disease. Even in developed countries now, one in five thousand children who gets measles will die."
Worldwide, measles kills almost 400 children every day while over 100 thousand babies are born every year with serious disabilities after being exposed to rubella in the womb.