New Zealand on the Cusp of Another Measles Outbreak: Lessons from 2019

Measles cases unconnected to international travel have been confirmed in New Zealand, suggesting the highly contagious disease has likely spread through communities. This is a stark reminder of the pending danger of a larger measles outbreak. To prevent transmission, a population immunity of around 95% is necessary, evenly distributed throughout communities. New Zealand does not have this level of vaccination coverage, and the main way to prevent an outbreak now is to focus on increasing the immunity of children and closing the "immunity gap" in the population.

Key Takeaways:

• New Zealand's measles vaccination rates are not enough to prevent an outbreak, with only 82% of two-year-olds fully immunised with two doses of the MMR vaccine.
• The recent measles cases suggest the disease has likely spread through communities, with a population immunity of around 95% necessary to prevent transmission.
• Without a national immunisation register, estimates suggest only around 80% of people born in the 1980s and 1990s are protected against measles.
• Immunisation coverage has consistently remained lower among Māori and Pacific children, creating pools of susceptible individuals for measles to take hold and spread.
• Recent research has shown that people who had measles in the 2019 outbreak had more hospital admissions not related to measles and more antibiotic prescriptions in the four years following the outbreak.
• The 2019 outbreak resulted in more than 2,000 cases, with about 35% requiring hospital care, and more than 250 cases in babies, with more than half of them hospitalised.
• Young adults who are unvaccinated are vulnerable to infection and can unintentionally bring measles home to their whānau (family), including unimmunised pēpi (babies).
• In late 2019, measles imported from New Zealand resulted in 5,700 cases in Samoa, including 1,800 hospitalisations and 83 deaths from measles.

Statistics:

• 82% of two-year-olds are fully immunised with two doses of the MMR vaccine (June 2025).
• Around 80% of people born in the 1980s and 1990s are protected against measles (estimated).
• 35% of people who contracted measles in the 2019 outbreak required hospital care.
• More than 2,000 cases of measles were reported in the 2019 outbreak.
• More than 250 cases of measles were reported in babies in the 2019 outbreak.
• 1,800 hospitalisations and 83 deaths from measles occurred in Samoa due to imported measles from New Zealand in late 2019.

Sources:

• The Conversation (Au and NZ) -- By Anna Howe, Senior Lecturer in Epidemiology, University of Canterbury
• Getty Images
• Author provided, CC BY-SA (http://creativecommons.org/licenses/by-sa/4.0/)
• Author provided, CC BY-SA (http://creativecommons.org/licenses/by-sa/4.0/)
• World Health Organization
• Health New Zealand
• Immunisation Advisory Centre
• Health Research Council
• Arthritis NZ
• GSK
• Starship Foundation