Philippines

UNICEF-WHO Philippines: Polio Outbreak Situation Report #4 (17 October 2019)

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Highlights

  • Synchronized polio vaccination campaigns were kicked off on Monday 14 October in National Capital Region (NCR), Davao City, Davao del Sur, and Lanao del Sur including Marawi City in response to a polio outbreak declared by the Philippines Department of Health (DOH) on 19 September 2019.

  • Current campaign in NCR to vaccinate almost 1.3 million children under 5 and over 400,000 in Mindanao on 14-27 October.

  • No further cases have been confirmed

  • Current polio outbreak based on 9 confirmed environmental samples and 2 human cases, resulting from persistently low routine immunization coverage, and poor sanitation and hygiene.

  • Circulating vaccine-derived poliovirus (cVDPV) is considered a public health emergency of international concern (PHEIC).

  • To protect against both cVDPV type 1 and 2, a dose of inactivated poliovirus vaccine (IPV) as recommended by the Emergency Committee under the International Health Regulations (2005) (IHR).

  • The Philippines administers IPV as part of the routine immunization program to children aged 3.5 months. Stocks are currently insufficient for the broader population.

Current Situation

Synchronized polio vaccination campaigns were kicked off on Monday 14 October in NCR, Davao City, Davao del Sur, and Lanao del Sur including Marawi City in response to a polio outbreak declared by the Philippines Department of Health (DOH) on 19 September 2019.

In NCR, 7 environmental samples from Tondo tested positive for cVDPV1. A 1 st round of vaccination was conducted in Manila City on 19 to 31 August with bivalent oral polio vaccine (bOPV), which protects against poliovirus type 1 and 3. Only 53.8% of the targeted children up to 5 years old were vaccinated.
The 2 nd and 3 rd round of the campaign aim to vaccinate almost 1.3 million children up to 5 years of age.

Two environmental samples from Manila and Davao tested positive for cVDPV2, followed by 1 positive human case from Lanao del Sur. A second human case from Laguna tested positive for immunodeficiency-related VDPV (iVDPV2). The currently ongoing vaccination campaign is targeting over 400,000 children up to 5 years of age in Davao City, Davao del Sur, and Lanao del Sur with monovalent OPV (mOPV), which only protects against poliovirus type 2. The 2 nd and 3 rd round will target over 3.1 million children in all 6 regions of Mindanao.

All samples were tested by the National Polio Laboratory at the Research Institute for Tropical Medicine (RITM), whereas sequencing and genetic analysis were done at the Global Specialized Laboratory National

Institute of Infectious Diseases (NIID) in Japan and additional genetic characterization provided by the United States Centers for Disease Control and Prevention (CDC).

The NIID and CDC confirmed all VDPV1 samples were genetically linked but did not find a genetic linkage with any other known VDPV1 detected globally, indicating new emergence.

Comparison done at NIID and CDC in poliovirus databases showed the Laguna case is not genetically linked with any other known type 2 poliovirus, indicating new emergence. All other VDPV2 samples are genetically linked.