health & science
Flawed forecasting? Why MMR vaccine ran out
In the face of a 2018 spike in global cases of measles and predictions the virus would reach New Zealand, Pharmac barely increased its forecast of vaccine demand
Pharmac’s forecast for how many doses of MMR vaccine would be needed for 2019 was around 150,000. To date, somewhere around 350,000 doses have been distributed, with rationing still in place.
Pharmac’s original forecast for 2019 was just 3384 doses above the amount forecast for 2018.
This was despite global cases of measles almost doubling in 2018, well-known vaccination gaps in New Zealand and predictions a measles outbreak was a plane ride away.
Pharmac say changes in global risk - such as the huge increase in global measles in 2018 - isn’t factored into its forecast.
“Changes in global risk is not explicitly factored in as it is not possible to predict with any certainty whether any additional vaccine would be required in a given year.”
When the virus arrived, first in Christchurch in March and then in Auckland in June, a call was initially made for all people who hadn’t had two doses of the vaccine to get immunised.
Almost immediately vaccine supplies ran low. A priority system was put in place with young children most at risk of hospitalisation getting high priority. Others were turned away and told to wait.
The outcome of New Zealand’s outbreak has been devastating. Two second trimester foetal deaths are thought to be a result of measles and 752 people of the 2154 people who contracted the virus have been hospitalised.
It’s also been a deadly export. At the time of writing, Samoa’s measles epidemic, sparked by a visiting infected Aucklander, has claimed 72 lives. Most are children younger than four.
Pharmac orders vaccine to cover routine vaccination that is part of the immunisation schedule, as well as extra doses to account for people catching up on missed doses.
For 2017, Pharmac forecast that 12,838 doses of MMR vaccine would be used each month. At that time, global measles cases were dropping from a 2014 peak. For 2018 its predictions were lower - just 12,115 doses per month.
During 2018, global measles cases increased from 155,000 to more than 333,000, yet Pharmac’s forecast for 2019 barely increased.
Pharmac’s forecast for monthly doses needed in 2019 was 12,557. Just 442 doses per month more than the previous year and 282 fewer than 2017’s forecast.
Newsroom’s back-of-the-envelope calculations of the number of under or unvaccinated New Zealanders show it's up to 1.3 million. Three Auckland DHBs estimate 152,000 to 182,000 doses would be needed just to vaccinate those in their areas.
Why so low?
In an Official Information Act response to Newsroom, Pharmac explained its vaccine ordering:
“Pharmac monitors vaccine usage and stock levels at the National and Regional Vaccines Stores and works to ensure a suitable safety buffer of stock is maintained to ensure continuity of supply. Relevant factors include supply lead times of at least six to nine months, storage capacity, risk of product expiry, risk of outbreaks, changes in vaccination take-up, demographic changes and seasonal factors.”
Newsroom asked for details about how any difference between 2018 and 2019 forecasts were calculated.
“While estimates are not recorded or held, a minor change in usage trends was taken into account.”
This did not include the global spike in measles cases.
On the front lines
Dr Jacqueline Allan’s practice is in the South Auckland suburb of Papakura. The shortage of vaccines meant patients were turned away.
“We had to turn away at least 100 people. That’s in a small practice of two GPS.”
Some of these were children just one month out from the target age range at the time.
“They were 14 months, not 15, and they were telling us we weren’t allowed to vaccinate anyone who was under 15.”
People in the 15 to 29 age group were also turned away, as were people in high-risk occupations such as early childhood care.
Rules around who was and wasn’t eligible to have the restricted vaccine supplies was confusing, Allan said.
“We had conflicting information and they kept expanding it, expanding it and changing it and changing it. It was a communication disaster.”
Allan thinks the ball was well and truly dropped.
“They’re meant to have plans in place for these sorts of things, and if they had a plan it didn’t work … we didn’t know what was going on.”
Earlier this year Newsroom spoke with Victoria University of Wellington’s faculty of health dean Professor Gregor Coster. He’s a former deputy chair of Pharmac.
He called the situation avoidable and predicted an increase in global cases of measles during 2018 should have been a sign an outbreak was likely.
“We should, at that stage, act fairly quickly to ensure we have sufficient measles vaccinations available.”
Coster said it wasn’t feasible for New Zealand to hold large stocks of vaccine in case of an outbreak, but did think a national catch-up campaign should be undertaken. Repeated requests over a number of years have been made to the Ministry of Health for this, but to date there’s no official announcement one will occur.
The Ministry of Health
Newsroom asked the Ministry of Health if it provided any guidance to Pharmac around vaccine-ordering and if it was satisfied with the number of necessary vaccines Pharmac forecast in 2019.
A spokesperson answered the first question.
“Pharmac is the agency responsible for monitoring demand and supply of vaccines and works closely with the Ministry on unexpected issues that may affect stock levels.”
A weekly teleconference is held to discuss vaccine level and the Ministry noted Pharmac did procure additional vaccine doses during a time when global measles cases increased by 300 percent.
The second question about whether the Ministry was satisfied with the forecast for 2019 went unanswered.
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