The Singapore imported polio case has raised concerns about the rare but serious disease. On 26 January 2025, a five-month-old Indonesian infant was medically evacuated to Singapore and later diagnosed with vaccine-associated paralytic poliomyelitis. While polio has been largely eradicated, this case highlights the importance of continued vigilance against the virus.
Details of the Imported Case
The Ministry of Health (MOH) confirmed that the infant had received one dose of the oral polio vaccine (OPV) and one dose of the inactivated polio vaccine (IPV) in Indonesia. In December 2024, she developed symptoms including fever, acute floppiness, and paralysis of the lower limbs. At that time, poliomyelitis was not suspected. However, after her condition worsened, she was flown to Singapore for treatment and admitted to the National University Hospital (NUH). She is currently in stable condition.
Image Source: Facebook / National University Hospital – NUH
Health authorities have assessed the risk of community transmission as low. The child was transported directly to NUH, where she was isolated to prevent further spread. Three of her close contacts, including family members and caregivers, have been quarantined as a precautionary measure.
What is Polio?
Polio, or poliomyelitis, is a highly infectious viral disease that primarily affects young children. The virus spreads through contaminated food, water, or direct contact with an infected person. While many infected individuals show mild or no symptoms, severe cases can lead to paralysis or even death.
In the past, polio was one of the most feared diseases, causing widespread outbreaks and leaving many survivors with lifelong disabilities. Thanks to vaccination efforts, the disease has been nearly eradicated in most parts of the world. Singapore has not had a locally transmitted case since 1978, and the last Singapore imported polio case was in 2006.
How Does Polio Spread?
Polio spreads mainly through:
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Consuming food or water contaminated with faeces from an infected person.
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Direct contact with an infected individual.
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Poor sanitation and hygiene practices.
Once inside the body, the poliovirus multiplies in the intestines and can enter the nervous system, leading to paralysis. In severe cases, it can affect breathing muscles, causing life-threatening complications.
Recognising Polio Symptoms
Polio symptoms vary from mild to severe. Many cases go unnoticed, but when symptoms do appear, they may include:
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Fever
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Fatigue
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Headache
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Vomiting
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Stiffness in the neck
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Muscle pain or weakness
Severe cases can result in irreversible paralysis, particularly in the legs. In rare cases, polio can be fatal if it affects the muscles involved in breathing.
Types of Polio
There are two main types of polio:
Wild Poliovirus (WPV)
This is the naturally occurring form of the virus. While WPV1 still exists in Pakistan and Afghanistan, WPV2 and WPV3 have been eradicated through global vaccination campaigns.
Vaccine-Associated Poliovirus (VAPP)
This occurs when the weakened virus in OPV mutates and regains the ability to cause disease. This is what happened in the Singapore imported polio case. While extremely rare, it can occur in immunocompromised individuals, which is why many countries, including Singapore, have switched to using IPV instead of OPV.
Preventing Polio: Vaccination is Key
There is no cure for polio, but it can be effectively prevented through vaccination. There are two main types of polio vaccines:
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Inactivated Polio Vaccine (IPV): An injectable vaccine containing killed virus, eliminating the risk of mutation.
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Oral Polio Vaccine (OPV): A cheaper, easily administered vaccine containing a weakened live virus. However, it carries a small risk of causing vaccine-associated polio in rare cases.
Singapore stopped using OPV in 2021 and now exclusively uses IPV. Under the National Childhood Immunisation Schedule, children receive five doses of IPV by the age of 11. These vaccinations are free for all Singaporean children at Community Health Assist Scheme (CHAS) General Practitioner clinics and polyclinics.
Is There a Risk of Polio Spreading in Singapore?
MOH has reassured the public that the risk of local transmission remains low. Singapore has maintained its polio-free status for decades due to:
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High vaccination coverage
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Strong hygiene and sanitation standards
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A robust disease surveillance system
Despite this, the Singapore imported polio case serves as an important reminder of why vaccination remains crucial. While polio is no longer a major global threat, isolated cases can still emerge, particularly in areas with lower immunisation rates. Ensuring that children receive their full vaccination schedule is the best way to keep polio at bay.
Final Thoughts
The recent Singapore imported polio case is a rare but serious event that highlights the need for continued vaccination and vigilance. While Singapore remains polio-free, the presence of cases in other parts of the world means that polio is not entirely gone. The best defence against this disease is ensuring that everyone, especially young children, is fully vaccinated. By maintaining high immunisation rates and good hygiene practices, we can continue to keep polio under control and prevent future cases.
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