MOH said the girl is immunocompromised, which means her immune system is not fighting off infections well enough. She was also previously vaccinated with one dose of oral polio vaccine (OPV) and one dose of inactivated polio vaccine (IPV) in Indonesia.

She had developed fever, acute floppiness and paralysis of the lower limbs in December 2024 while in Indonesia, but was still not diagnosed with polio at the time.

On Jan 26, she was medically evacuated for treatment of her symptoms and admitted directly to the National University Hospital (NUH) upon arrival here.

The infant is currently in stable condition, and there is a low risk of community transmission, MOH said.

MOH added that the infant was taken directly to NUH upon landing in Singapore and also isolated upon admission. Proper measures were also taken to prevent further transmission after she was suspected of poliomyelitis infection.

Three close contacts of the infant - family members or caregivers - are currently quarantined as a precautionary measure.

Polio is caused by the poliovirus and can spread through food infected with faecal material.

Vaccination is the most effective protection against polio, alongside maintaining high standards of hygiene and sanitation.

Currently, there are two vaccines for polio: OPV, which contains live attenuated (weakened) poliovirus, and IPV, which does not contain any live poliovirus.

Many countries have progressively switched to IPV, and Singapore stopped using OPV in 2021, MOH said.

Vaccine-associated paralytic polio is extremely rare and occurs only when an individual develops the condition after receiving OPV. The risk is also higher for those who are immunocompromised and for whom IPV is recommended instead of OPV.

MOH noted that Singapore has not reported any locally acquired cases of polio since 1978, with the last polio case reported in 2006 being an imported one.

Under the National Childhood Immunisation Schedule (NCIS), children receive a total of five vaccine doses – three IPV doses for infants at two, four and six months, with another two booster doses of IPV at 18 months and 10 to 11 years old, ...