health & science
Uptake of free life-saving vaccine ‘dismal’
The uptake rate of a free whooping cough vaccine that can save babies' lives is being described as dismal
When Anna Jackson gave birth to her first child in 2011 she didn’t give whooping cough much thought. She knew New Zealand had been vaccinating against it for years and thought it was practically eradicated.
Her son was due to get his first vaccination at six weeks of age, the normal age for the first of four whooping cough shots that are part of New Zealand’s immunisation schedule.
By the time he was five weeks old, he already had whooping cough and was fighting for his life.
Despite years of consistent immunisation, the number of whooping cough cases in New Zealand remains stubbornly high, with an outbreak occurring every three to five years. Each year, whooping cough hovers between ranking second or third as our most common notifiable disease.
For adults, whooping cough - also known as pertussis or the 100-day cough - can be so severe, coughing fits can crack ribs.
For babies the disease is worse. Around 50 percent of children younger than a year old will be hospitalised. Of those hospitalised, one to two children in every 100 will die. Others will suffer brain damage, blindness, deafness or paralysis.
The outbreak, which started in 2011, infected around 11,000 people and killed three children. Two of the babies who died were too young to be immunised.
Jackson said her son’s illness started as coughing fits, which caused him to vomit milk. Increasingly concerned, she made visits to her doctor as well as an after-hours clinic. She was told it was probably a passing virus.
It was a Plunket nurse who spotted how serious his condition was. She recommended an ambulance.
“That night I stayed in the hospital with him and they were resuscitating him all night long,” said Jackson.
After five days of not keeping milk down, her son was starved, dehydrated and frequently stopped breathing. Jackson watched as two specialists performed chest compressions and gave him oxygen.
“He was just giving up breathing. He didn’t have any energy left.”
The decision was made to airlift him from Wellington to Starship Hospital in Auckland. Jackson was told if she was religious, now would be a good time to seek spiritual guidance.
“I was sent home to pack. I remember looking at the baby monitor in the kitchen, thinking to myself, jeez, I hope we need this when we come home - that we would still have him.”
He spent a week in intensive care in an induced coma with tubes helping him breathe. When he was finally able to go home several weeks later he was “just skin and bones”. However, as far as she’s concerned, their family dodged a bullet.
She wants people to understand whooping cough is more than a bad cough - and to get vaccinated. She’s not sure who her son caught the disease from.
“I wish I could have taken the person and shown them him struggling to breath with tubes coming out of everywhere.”
There’s a chance whoever passed the airborne disease on to Jackson’s son might have been immunised at some point in the past.
Neither getting vaccinated, nor catching whooping cough, guarantees life-long immunity, according University of Auckland vaccinologist Helen Petousis-Harris.
“That’s the first problem, there’s no permanent protection against the disease.”
Petousis-Harris estimates vaccine protection lasts for around five to 10 years. This is why adults who were vaccinated as children sometimes get the disease.
“The other problem is that the current vaccine does little to prevent carriage and transmission. You can be perfectly well and not have a cough yourself, but you could carry and transmit it to others.”
The pregnancy booster
As well as people ensuring their vaccinations are up-to-date there’s another way Jackson’s son might have been protected.
A whooping cough booster shot given during pregnancy allows antibodies the mother creates cross the placenta. This provides protection until the baby is old enough to be vaccinated. It's safe and 90 percent effective.
The vaccine has been available free in New Zealand since 2013, too late for Jackson’s first son who caught whooping cough, but she did take it during her second pregnancy.
She’s one of the estimated 13 percent of pregnant women who took it in the first two years of its availability.
Petousis-Harris describes this level of uptake as dismal.
“We were one of the first countries in the world to introduce it free for pregnant women but we’ve done very poorly in actually delivering that.”
Petousis-Harris said the vaccine was funded, an announcement was made, and “that was pretty much that”.
“There’s been very little health promotion, information provided and communication about it.”
One Canterbury survey showed for women who did not receive the vaccine during pregnancy, 73 percent said they were not aware it was available.
Another analysis of Auckland’s infant whooping cough cases in 2015 to 2016 showed similar results. Over 80 percent of mothers did not receive a booster during pregnancy. Most were not offered it, or did not get it because of a “recall systems failure”.
A study looking at maternal vaccination rates in Rotorua and Taupō/Tūrangi in 2017 showed the importance of a recall to the GP. While women routinely visit a GP at the start of their pregnancy, they don’t tend to go in the third trimester when the vaccine was given.
In Taupō/Tūrangi, all mothers were called back in the third trimester. The area’s vaccination rate was 76 percent. For Rotorua, where call-backs weren’t done, the vaccination rate was 45 percent.
From July 2019, the eligibility for the pregnancy booster shot was widened to include second trimester as well as third trimester.
To lift rates across the country, Petousis-Harris thinks communication to parents, as well as systems and resources to ensure the vaccine is accessible, are needed.
The latest outbreak of whooping cough - which began at the end of 2017 - appears to have ended around May this year. Another outbreak is likely within three to five years.