health & science
Polio: lingering effects and the last mile
With just 29 cases of wild-caught polio reported last year, the polio virus is on the verge of being eliminated. In the second article in a series on vaccine-preventable diseases Farah Hancock reports on the 'last mile' of eradication and talks to a New Zealander still affected by the virus.
Nelson’s Brian Robinson is learning how to walk for the third time.
He was 17 months old and just gaining confidence on his feet when he contracted polio in 1949.
The virus paralysed his left leg and he spent six months in hospital recuperating, and then another six months in hospital learning how to walk again. Much of his childhood was spent wearing a calliper.
Spread by faeces, the polio virus multiplies in the throat and gastrointestinal tract. It moves through the bloodstream to the central nervous system where it starts to destroy motor neurons. These are responsible for things we take for granted: swallowing, breathing and moving arms and legs. Anybody could catch the virus, but children are the most susceptible.
The outbreak in the late 1940s which infected Robinson caused widespread panic in New Zealand. Swimming pools were closed, beaches were considered dangerous to swim at, schools were shut. Hamilton's Christmas parade was allowed to proceed on the proviso children stand at least six feet apart.
Many who caught the virus would experience a mild illness, with a fever, headache and sore throat. Others would develop paralytic polio and their limbs would become floppy and unresponsive. Some lost the ability to breathe unaided and needed the help of an iron lung.
The virus killed between 2 and 10 percent of the people it infected. In New Zealand, 821 people died between 1908 and 1961. It paralysed countless others before the effects of the vaccination programme which started in 1956 took effect.
The virus caused limbs to wither as unused muscles wasted away. Leg callipers on children taking hesitant, lurching steps were a tell-tale sign of a polio survivor.
Since Robinson caught the virus, his left leg has had no strength and is only useful as a prop.
“I could run - do the hoppity-skip run. I played friendly softball.”
In school lunchtime games of soccer, he sometimes played goalie.
‘Oh it’s our choice you know,’ someone will say. Yeah, sure. But do you want to go through what I went through? Do you want your kids to go through what I went through?
He said he’s tried to live life to the fullest. He’s hunted and fished and has volunteered for St John Ambulance.
“I was in the volunteer fire brigade, at Tapawera for a while until the Fire Service decided that everybody needed to have a full medical and they kicked me out.”
He maintains he's not let the effects of the childhood disease slow him down, and for much of his life he hasn't. Unfortunately for Robinson though, polio hasn’t finished with him.
Eighteen years ago he realised he was having more difficulty moving and was getting tired easily. Robinson, and at least 100 other New Zealanders who had polio as children, are now experiencing the second wave of the disease: post-polio syndrome.
The exact cause of post-polio syndrome is unknown. One theory is that undamaged motor neurons are doing extra work to make up for the ones the virus destroyed. As those who had polio get older, the remaining motor neurons are wearing out.
Robinson counts himself lucky to not to be experiencing breathing difficulties or pain that other people with post-polio syndrome experience.
There’s no treatment for post-polio syndrome and no cure. Even getting a correct diagnosis is an issue, with many doctors unaware of its existence.
Robinson has new leg braces to help him cope with the deterioration in movement. The dynamic braces will help him walk better but take some getting used to. Unlike traditional braces, these don’t bend at the ankle.
“After 70 odd years of walking one way I’ve got to change that now and convince the brain that I’ve got to do it differently.”
The World Health Organisation recently listed vaccine hesitancy as one of 2019's top 10 global threats to health.
It’s not just his brain that’s going to need to adapt. Little things like trousers have become a dilemma. He can’t wear trousers under the braces because they are too bulky, trousers over the top don’t work because the braces makes them too tight. He’s considering getting custom-made trousers with zips on the side. People have suggested a kilt. Laughing, he said he worries winter might be a bit cold.
Robinson now works with Polio NZ to help others with post-polio syndrome.
He said he gets “toey” with people who don’t believe in vaccination. There’s no cure for polio; vaccination is the only hope of preventing it.
“I get real angry when people won't vaccinate their kids. ‘Oh it’s our choice you know,’ someone will say. Yeah, sure. But do you want to go through what I went through? Do you want your kids to go through what I went through? Do you want to go through what my parents went through when I had polio?”
The World Health Organisation (WHO) recently listed vaccine hesitancy as one of 2019's top 10 global threats to health.
Polio vaccination is still given as part of New Zealand’s childhood free schedule of vaccinations. Children receive four doses of the vaccine between the ages of six weeks and four years old. The last case of wild-caught polio in New Zealand was reported in 1977.
“You talk to people, ‘Oh, polio, that's not around anymore. There’s no such thing. You know, it's all gone. It's been eradicated’. Well, yeah, In New Zealand it has, but in overseas countries it's still there,” said Robinson.
The last mile is the hardest
The adage that the virus is an aeroplane journey away is very true. Polio still exists in the wild in Pakistan, Afghanistan and Nigeria.
Led by WHO, a concerted eradication effort through vaccination is being made and the number of wild-caught polio cases has reduced from 350,000 in 1988 to 29 in 2018. To date, smallpox is the only human virus to be eradicated. Achieving the same result for polio is tantalisingly close.
“I liken vaccination to a fire. People live right up close to the bush and forest and have all this dry grass around. If you don’t protect your property, you’re going to lose it. Vaccination is the same."
With the easily recognisable symptoms of smallpox, "ring vaccination" could be used to vaccinate every person in contact with an infected person. With polio, sometimes people have no easily recognisable symptoms. By the time one case of paralysis is found, it's likely hundreds of people have, and are spreading, the virus. The best way to eradicate the virus is to vaccinate the entire population.
Eradication is only official when a country has had no polio cases for three consecutive years.
Getting the vaccines to remote areas, conflict zones and battling distrust has hindered the effort to fully vaccinate every child.
In Pakistan, the 2011 killing of Osama bin Laden led to a distrust of vaccinations. A doctor involved in a hepatitis B vaccination programme, possibly unwittingly, led US agents to bin Laden’s compound. This is said to have sparked suspicion polio vaccinations were part of a western plot to sterilise the population. Several health workers administering vaccines were murdered. By 2014, the number of polio cases in Pakistan reached 306, the highest number since 2000.
It has since dropped. In 2018, just 12 cases were reported and only two polio vaccinators were killed. There’s an effort to promote the work of public health workers delivering vaccines. A video and photo of a worker pushing his way through waist-deep snow to take vaccines to a village was shared widely online. The worker was invited to meet Pakistan's Prime Minister Imran Khan who described him as a hero.
Another issue to contend with is vaccine-derived polio. There are two types of polio vaccine. The type administered by injection uses inactive virus. It’s based on the vaccine Jonas Salk created and is the version New Zealand and many other developed countries now use.
The other version, created by Albert Sabin and taken orally, uses weakened live virus. It gives longer-lasting immunity than the injected version and is less susceptible to temperature, making it easy to store and transport. It is also easier to administer.
There is a risk though. Faeces from children vaccinated with the oral version can carry live virus while their body builds up antibodies. Circulating in the wild, the excreted virus can mutate and go on to infect others. In areas with poor sanitation and low vaccination rates, this can be a problem.
Less than 10 hours' flight from New Zealand, Papua New Guinea has recently experienced an outbreak of vaccine-derived polio. Declared free of polio in 2000, vaccination rates have more recently dropped from 80 percent to 30 percent. In September 2018, 12 cases of polio were found and one person died. Since September, vaccination efforts have increased to attempt to halt the spread.
Similar vaccine-derived outbreaks have occurred in Syria, Somalia, Nigeria and the Democratic Republic of Congo. US researchers announced in November a freeze-dried version of the injectable vaccine had been tested and found to work in mice. However, even if it is developed and storage and transport becomes easier, it would still require people trained in giving injections to administer it.
The Ministry of Health website suggests anyone who is travelling to countries where polio is present get a vaccination booster shot if they were vaccinated more than 10 years ago.
Polio survivor and former fire service volunteer Robinson compares polio prevention to the recent fires in Nelson.
“I liken vaccination to a fire. People live right up close to the bush and forest and have all this dry grass around. If you don’t protect your property, you’re going to lose it. Vaccination is the same. If you don’t put a barrier there to prevent things, then you’re going to lose it.”
Read more: Smallpox: A disease in deep-freeze