In December 2019, Malaysia reported its first polio case in 27 years, detected in Sabah state, leading to outbreak investigation and a targeted immunization campaign to control further spread of the disease.
The case was confirmed as circulating vaccine-derived poliovirus type 1 (cVDPV1) after sequencing of an isolate by the Victorian Infectious Diseases Reference Laboratory (VIDRL), Australia. Subsequently, three more cVDPV1 cases were reported in Sabah state through acute flaccid paralysis (AFP) surveillance. What was once thought to be an eradicated disease in the country had now re-emerged.
During the early part of the outbreak, a team from the Malaysia Epidemic Intelligence Program (EIP) assisted in outbreak investigation, aiming to identify a possible source of the outbreak, as well as any missed cases of AFP. Although the source could not be identified, it was hypothesized that infection may have come from asymptomatic individuals. Findings were communicated to the State Health Department and used to develop an outbreak management plan.