Polio is back in the global conversation again over concerns the disease is spreading in London and New York.
Let's get you up to speed on what's been happening — and answer your basic questions about the disease.
Viruses spreading in New York and London
In July, the US reported a polio case in suburban New York City — the country's first case in nine years.
Last week, health authorities in New York confirmed polio virus has been detected in sewage there, which they said suggested there had been local transmission of the virus.
"We urge unvaccinated New Yorkers to get vaccinated now," they said.
Last week, London health authorities confirmed the virus was spreading in the city for the first time since the 1980s. They first raised the alert on finding the virus in sewage samples in June.
The UK Health Security Agency has identified 116 detections from 19 sewage samples in London this year, but no cases have been reported.
In response, London health authorities launched a vaccine booster program for children aged below 10 years.
What is polio?
It's highly infectious viral disease that gets into the nervous system and can cause total paralysis within hours.
Its proper name is actually poliomyelitis, but it's commonly known as polio.
Up to 90 per cent of cases are asymptomatic and most people who do experience symptoms make a full recovery, the World Health Organization (WHO) says.
However, about 0.5 per cent of cases experience paralysis — most often in the legs — which is often permanent.
Of that 0.5 per cent of patients who experience paralysis, 5 per cent to 10 per cent die when the muscles that help them breathe become immobilised.
What are the symptoms of polio?
Initial symptoms include:
- fever
- fatigue
- headache
- vomiting
- stiffness in the neck
- pain in the limbs.
How does polio spread?
Typically through the faecal-oral route, but can also be spread by contaminated food and water.
The virus enters the body through the mouth, multiplies in the throat and intestines and is excreted in faeces for weeks after the initial infection.
So, it typically spreads in places with poor hygiene.
Is there a cure?
No.
However, there are treatments that focus on alleviating the symptoms.
Antispasmodic drugs, heat therapy and physical therapy can help improve mobility, but this doesn't reverse polio paralysis.
Is there a vaccine?
Yes and, if given correctly, it can protect a person from the disease for life.
While some Australians received their polio vaccine via oral drops in the past, the vaccines Australia uses today are only given via injection.
The IPOL vaccine is an injection that's just for polio.
However, there's also a handful of other combination vaccines administered in Australia that protect people against polio as well as other diseases — such as tetanus and diphtheria:
For children under 10 years of age, these are the combination vaccines:
- Hexaxim
- Infanrix hexa
- Infanrix IPV
- Quadracel.
For adults, teenagers and children over 10 years of age:
- Adacel Polio
- Boostrix-IPV.
Wasn't polio eradicated?
No, not entirely.
Most countries are free of polio thanks to vaccines, but the polio virus still exists.
The Western Pacific region, which incudes Australia, was declared polio-free in 2000.
Polio remains endemic in Afghanistan and Pakistan, according to the Polio Global Eradiation Initiative.
Why is polio spreading in the UK and US?
Under-vaccination, experts say.
Vaccine hesitancy was already an issue before COVID-19 hit, but the United Nations said the pandemic had caused the worst disruption to routine immunisation programs in a generation.
Earlier this month, the New York City Department of Health said 13.8 per cent of children aged between six months to five years old had not been vaccinated.
There's two main forms of polio virus: There's the wild-type virus, which is seen in endemic countries, then there's what's known as vaccine-derived polio — the type detected in New York and London's wastewater.
The latter stems from the use of an oral polio vaccine containing weakened live virus.
Recipients of this type of vaccine shed virus in their faeces for a few weeks and, in under-vaccinated areas, this can then spread and mutate into a harmful version of the virus.
Neither the US nor the UK uses this live vaccine any more, but other countries do and experts say this allows for global spread, particularly as post-pandemic travel picks up.
In 2020, there were 1,081 vaccine-derived polio cases, roughly triple the amount of the previous year.
So far, in 2022, there have been 177 vaccine-derived polio cases, a drop that has been attributed to efforts to get polio vaccination campaigns back on track.
How do I know if I've been vaccinated against polio?
By checking your immunisation history statement.
You can do that online through the Express Plus Medicare mobile app or through your myGov account.
You can also call the Australian Immunisation Register on 1800 653 809 and ask them to mail your immunisation history statement to you, however, it could take around two weeks to arrive in the post.
ABC/Reuters
