Polio in Sabah, Malaysia

According to the Ministry of Health, a polio case has recently been reported in Malaysia. The case was confirmed to be infected with the vaccine-derived poliovirus type 1 (VDPV1). This is the first case after the country has been Polio-free for 27 years.

The patient is a 3-month old baby boy from Tuaran, Sabah. The patient is in a stable condition and is undergoing treatment in an isolation ward.

Advice

These patients are not infected with the wild polio virus. A potential, but rare, adverse effect of the oral polio vaccine (OPV) is the ability to recombine to a form that may cause neurological infection and paralysis. This is believed to be a rare event, but outbreaks of vaccine-associated paralytic poliomyelitis, caused by a circulating vaccine-derived poliovirus (VDPV), have been reported. Circulating VDPVs occur when routine or supplementary immunization activities are poorly conducted and a population is left susceptible to poliovirus, whether from vaccine-derived or wild poliovirus. Hence, the problem is not with the vaccine itself, but low vaccination coverage. Outbreaks of paralysis due to the vaccine derived strain tend to occur in areas where polio vaccination levels have not been maintained in the general population.

Travellers to any country that reports cases of polio (whether wild or vaccine-derived type) can reduce their risk of exposure to poliovirus by ensuring that their childhood vaccinations, including polio, are up-to-date prior to travelling. For added protection, travellers who are visiting countries where transmission of the polio virus is continuing should receive an additional dose of oral polio vaccine or inactivated polio vaccine within 4 weeks to 12 months before travelling.