New research from the University of Otago (Christchurch) shows not enough children under the age of 5 are protected against measles to stop a potential national outbreak.
Lead author Dr Nienke Hagedoorn said coverage for the first MMR vaccine had decreased from 95.1% for children born in 2017, to 88.9% for those born in 2020.
She said more than 95% immunisation coverage for measles was needed to prevent community transmission in children under 5.
"This is important, because young people who are unvaccinated are at high-risk for measles-related complications, such as hospital admissions or even death," she said.
Researchers used data from the National Immunisation Register to investigate how many children born between 2017 and 2020 in New Zealand received the first and second MMR vaccine.
Results showed children of Māori ethnicity had the lowest coverage for the first vaccine and this declined over time, from 92.8% for the 2017 birth cohort, to 78.4% for 2020.
The number of children who received the first vaccine is declining in all Te Whatu Ora locations.
Six locations — Bay of Plenty, Lakes, Northland, Tairawhiti, West Coast and Whanganui — had on average, less than 90% coverage for the first vaccine during the study period.
Overall, the coverage for the first vaccine was 92.5% for children born between 2017 and 2020.
"Since the borders in New Zealand have fully opened and the number of measles cases around the world has increased, the chances of measles being imported into New Zealand have also gone up."
Dr Hagedoorn said nationwide catch-up immunisation programmes were urgently needed to improve immunisation coverage and prevent an outbreak.
