health & science
NZ ‘could have protected’ Samoa from measles
Officials were warned for years a vaccination catch-up campaign was needed but failed to act. In July the Ministry of Health was told New Zealand poses a measles threat to Pacific nations.
A measles outbreak in Samoa suspected to be responsible for the death of a one-year-old was “inevitable”, according to an expert who thinks New Zealand could have done more to prevent it.
This week, Samoa declared a measles epidemic with seven confirmed cases. It's thought the disease was spread from an infected Aucklander who visited in August.
In July, the Ministry of Health was told by a national vaccine committee the current situation in New Zealand posed a threat to Pacific nations.
University of Auckland vaccinologist Dr Helen Petousis-Harris said she was hugely concerned for Samoa.
“Potentially there’s quite a lot of measles in their community now.”
The situation is exacerbated by a recent drop in immunisation rates in Samoa after a vaccine botch-up caused the deaths of two babies. Anaesthetic was mistakenly mixed in a multi-dose vial of vaccine by medical staff.
At one point Samoa’s vaccination rate was 80 percent for the first of two MMR vaccine doses. Petousis-Harris said after the deaths in 2018, this dropped to 31 percent.
She thinks New Zealand could have taken steps to reduce the likelihood of exporting the highly-contagious and deadly disease.
“We could have protected them by not having a problem ourselves.”
The gaps in MMR vaccine coverage of Pacific Islanders living in New Zealand have been known for decades. A 1991 vaccine coverage survey showed only 42 percent of Pasifika two-year olds were vaccinated.
In 2018, New Zealand contributed to almost half of all Samoa's visitor numbers with over 81,000 visits originating from New Zealand. Visiting friends and family was the top-listed reason for travel.
History of inaction
Experts say there have been repeated calls for New Zealand to conduct a national catch-up campaign to plug immunisation gaps in New Zealand.
The National Verification Committee for Measles and Rubella Elimination, which reports New Zealand’s measles status to the World Health Organisation, flagged in July that steps should have been taken to address vaccine coverage gaps.
It said targeted catch-up campaigns were required, particularly in Auckland.
The risk a New Zealand outbreak posed to other countries was also raised:
“Steps should be taken to prevent measles spreading to Pacific Island nations from New Zealand, via communications to Pacific Island governments on vaccination requirements.”
At the time, the Ministry of Health’s director of public health, Dr Caroline McElnay, said she welcomed the recommendations. The focus, however, appeared to remain on business-as-usual rather than a national campaign to plug current gaps.
“The Ministry’s immediate priority is to ensure that our national immunisation schedule remains on track. This will prevent immunity gaps developing in the future.”
Calls and recommendations for a catch-up campaign stretch back several years.
A detailed document produced in 2017 by the Ministry of Health looked at 12 options suggested by the National Verification Committee for Measles and Rubella Elimination to target 12 to 32-year-olds. A SWOT (strengths, weaknesses, opportunities and threats) analysis was completed for each option.
The options include ways of trying to work out who needs to be vaccinated as well as ways to reach them. A common listed threat to the many options was that the "opportunity cost" of various options would need to be weighed up against other primary care priorities.
Research published in 2017 shows outbreaks come at a huge cost, estimating the first 183 cases of measles during the 2014 outbreak cost over $1 million. This was due to earnings lost, case management and hospitalisation costs.
The research found the benefit-cost ratio to vaccinate older children, teens and adults who may have missed out on vaccinations "economically efficient" as long as the cost per person remained below $100. So far, 590 people are listed as being hospitalised during the current outbreak.
Another option suggested was to seek funding for a pilot programme at a DHB level. It was thought this could improve immunisation rates in some DHBs. A listed weakness of this was:
"Pilot may imply that current systems are not optimal and improvements could be made, resulting in loss of public confidence.”
There have been 1840 confirmed cases of measles in New Zealand this year and two second trimester foetal deaths, as well as the seven confirmed cases and death of the baby in Samoa suspected to be linked to New Zealand's outbreak.
The school holidays may result in further spread as Aucklanders with the virus travelled to other areas.
Twelve hundred people who attended a church camp in Rotorua have been told a child at the camp had the virus. In Wellington, two cases were confirmed and people who attended a comedy show have been warned to watch for symptoms.