Singapore Reports Imported Case of Vaccine-Associated Polio; Low Community Transmission Risk
A recent case of vaccine-associated paralytic poliomyelitis in Singapore has stirred concern. The Ministry of Health (MOH) confirmed this occurrence, revealing that a five-month-old female Indonesian infant, who arrived in Singapore on January 26 for medical treatment, is the patient in question. This infant had been immunocompromised and previously vaccinated with one dose of oral polio vaccine (OPV) and one dose of inactivated polio vaccine (IPV) in Indonesia. The gravity of the situation escalated in December 2024 when she exhibited symptoms of fever, acute floppiness, and paralysis of the lower limbs while in Indonesia. Shockingly, poliomyelitis was not initially suspected by her attending physician. This narrative took a dramatic turn on January 26 when she was medically evacuated for treatment of these symptoms, promptly admitted to the National University Hospital (NUH) upon arrival in Singapore, where she currently remains in stable condition. This case has raised concerns about community transmission risk, although MOH has assured that the likelihood is low.
Polio, more formally known as poliomyelitis, is a highly contagious disease that targets muscles and nerves, sometimes leading to permanent limb paralysis in severe cases. The HealthHub portal explains that most individuals infected with polio either remain asymptomatic or exhibit minor symptoms that eventually subside. The transmission of polio typically occurs through contact with infected persons, often via oral exposure to bodily fluids or fecal matter. Initial symptoms may include fever, fatigue, headache, vomiting, neck stiffness, and limb pain. The disease manifests in various forms, with nonparalytic polio inducing flu-like symptoms but not resulting in paralysis, as per Mayo Clinic. On the other hand, paralytic polio is the most severe manifestation, characterized by intense pain, tingling sensations, muscle spasms, and progressive muscle weakness leading to eventual paralysis. In severe cases, patients may experience respiratory muscle paralysis and swallowing difficulties, making it a life-threatening situation.
### The Importance of Vaccination
Vaccination emerges as the primary shield against poliomyelitis, alongside strict adherence to sanitation and hygiene practices, according to the health ministry. Two types of vaccines are available for polio prevention – OPV, containing live attenuated poliovirus, and IPV, devoid of live poliovirus. In a bid to combat this menace, many countries have transitioned to IPV, with Singapore ceasing the use of OPV in 2021. Vaccine-associated paralytic poliomyelitis, a rare adverse event, arises when individuals experience paralytic polio post-OPV administration. Immunocompromised individuals face a heightened risk, prompting the recommendation of IPV over OPV for this demographic. Despite the rarity of this condition, Singapore has remained vigilant, maintaining a polio-free status since 1978. The last reported polio case in 2006 was imported, emphasizing the nation’s commitment to high vaccination coverage, rigorous environmental hygiene, sanitation standards, and robust surveillance systems.
Under the National Childhood Immunization Schedule (NCIS), children receive five vaccine doses, including three IPV doses for infants at two, four, and six months, with additional IPV booster shots at 18 months and 10 to 11 years. By eliminating live virus content, IPV poses no risk of vaccine-associated paralytic poliomyelitis. The NCIS ensures that all Singaporean children have access to free vaccinations at Community Health Assist Scheme General Practitioner clinics and polyclinics, underscoring the government’s unwavering dedication to public health.
In these critical times, vaccination remains the cornerstone of disease prevention, safeguarding our communities against the threat of infectious diseases. The recent case of vaccine-associated polio in Singapore serves as a poignant reminder of the importance of vaccination, underlining the need for stringent surveillance, timely intervention, and public health awareness campaigns. Through collective action and a steadfast commitment to vaccination initiatives, we stand a chance at curbing the spread of infectious diseases and safeguarding our most vulnerable populations. Let this incident not only be a wake-up call but a rallying cry for us to prioritize health, safety, and well-being in our communities.
