Auckland's health services are struggling with an outbreak of measles, which is a highly contagious disease.
Immunization policies in foreign countries are not enough to prevent measles outbreaks and vaccines must be made mandatory for children when they start school, new research shows.
Information has been published on BMC treatment and focuses on Australia, Ireland, Italy, Singapore, South Korea, the United Kingdom and the US.
That happened when Auckland was in the midst of a measles outbreak, with 54 confirmed cases.
To achieve and maintain measles elimination in the countries studied, which have the same policies as New Zealand, further immunization efforts may be needed, said the study.
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A research team at the Bruno Kessler Foundation and Bocconi University in Italy used a computer model to simulate measles evolution between 2018 and 2015 in seven countries.
They focused their analysis on countries with routine two-dose measles vaccination programs and with high levels of primary school involvement.
The researchers found that if the current vaccination policy remained the same until 2050, the proportion of the population likely to get measles would only remain under 7.5 percent in Singapore and South Korea.
One of the study authors, Dr Stefano Merler, said the countries studied would "greatly benefit" by introducing mandatory vaccines at school – in addition to the current immunization program.
"In particular, we find that this strategy will enable Britain, Ireland and the US to achieve stable herd immunity levels in the coming decades, which means that a high proportion of individuals are immune to disease to avoid future outbreaks.
"To be effective, mandatory vaccination when entering school needs to cover more than 40 percent of the population."
Auckland is currently experiencing a measles outbreak, a highly contagious and potentially life-threatening viral disease.
Auckland Regional Public Health Services have contacted more than 2,700 Auckland residents who may have been exposed to the disease so far this year.
About one in 10 people who suffer from measles need to be hospitalized, and around 30 percent of cases experience complications.
Complications include ear infections, which can cause permanent hearing loss, diarrhea, pneumonia, seizures and in rare cases, brain swelling.
Measles symptoms include high fever, runny nose, coughing and aches, red eyes. A few days later the rash appears on the face and neck before spreading throughout the body.
For more information or advice on measles, contact Healthline at 0800 611 116 or visit the ARPHS website or the Department of Health.