Poliomyelitis is caused by the highly-infectious poliovirus that replicates in the intestines and attacks the nervous system, where it can cause paralysis in hours. It strikes mainly children under age 5, and in the past left millions in calipers or wheelchairs with withered limbs, and killed many by paralyzing their lungs.
Then in 1955, a vaccine was discovered, and in 1988 the World Health Organisation (WHO) launched a campaign to eradicate the disease. It was highly successful, and by 2006 South Africa had joined the vast majority of countries declared polio-free. But in 2017, WHO quietly withdrew South Africa’s certification – putting us among seven African countries not certified polio-free.
The reasons WHO gave were concerns about our surveillance systems and our immunisation rates. The surveillance systems problem centres on health professionals, mainly in high volume hospitals, not properly investigating all patients presenting with “acute flaccid paralysis”, the main sign of polio, reports Dr Melinda Suchard, head of the Centre for Vaccines and Immunology at the National Institute for Communicable Diseases (NICD), and a lecturer at the University of the Witwatersrand. “Not enough cases with neurological weakness were being identified, notified and investigated, with stool samples sent to the NICD.”
The immunisation rate problem centres on the WHO and UN Children’s Fund estimated that just 75% of children in South Africa are vaccinated.
In response to the immunisation problem, in March this year, the Department of Health launched a national immunisation coverage survey to reach about 9 000 households in all 52 health districts in the country, targeting children aged 1 and 2. The results are due out in September, but research has already suggested that the Eastern Cape and North West are falling short in polio vaccination coverage.
In response to the surveillance problem, the Department of Health has set a target for South Africa to find four cases of acute flaccid paralysis per 100 000 children and investigate them for polio. The Minister of Health has also put polio on the agenda of the National Health Council and spoken about it during hospital visits.
Who is at risk?
Children under age 5 are most at risk, especially among groups who refuse to vaccinate, migrants, refugees, and those living either in remote areas with poor transport, or in inner-city slums and informal settlements.
Although Shelina Moonsamy, medical technologist for the Centre for Vaccines and Immunology at the NICD, reports that the last confirmed case of polio in South Africa was in 1989, the risk is high. This is because of continued transmission in other African countries and the high degree of movement and migration of people to South Africa, along with our ‘sub-optimal’ immunization coverage, notes the NICD.
How do you get poliovirus?
Poliovirus multiplies in the infected child’s intestine and is spread mainly through their faeces, which can enter the water supply when there’s poor sanitation, and contaminates food and utensils.
Signs of infection are non-specific at first – fever, tiredness, headache, sore throat, vomiting – but can progress to severe muscle pain, stiffness of the neck and back, and pain in the limbs. The NICD notes that worldwide, one in 200 infections lead to irreversible flaccid paralysis, most often of the legs, when the virus enters the central nervous system and replicates. Around 5-10% of those paralyzed die when their breathing muscles are immobilised.
How is polio treated?
Polio is diagnosed by stool samples of cases that present with acute flaccid paralysis, says Moonsamy. There’s still no cure, but physical therapy can help give the most function possible after paralysis, and prevent other deformities from developing.
The key is prevention, which centres on vaccination. In South Africa, under the revised Expanded Programme on Immunisation schedule from December 2015, the vaccine is given at birth and at six, 10 and 14 weeks of age, and a booster at 18 months.
It’s vital to see that your child has his or her shots. If you’ve missed out on any, it’s important to contact your health provider or clinic.
For more information, visit www.nicd.ac.zaunder the “Diseases A-Z” tab.
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