A. Situation analysis
Description of the disaster
On 19 September 2019, the Department of Health (DOH) confirmed the re-emergence of polio in the Philippines and declared a national polio outbreak1 . This follows a confirmed Vaccine Derived Poliovirus Type 2 (VDPV2) case in a three-year old child in Lanao de Sur (Mindanao). Subsequently, another case of polio (strain to be confirmed) was reported on 20 September and this time in a five-year-old boy from Laguna, bringing the total number of people afflicted with the disease to two. The re-emergence of the disease comes almost 20 years since the Philippines was declared polio-free in 2000. The last known case of wild poliovirus recorded in the Philippines was in 1993.
Between 1 July and 27 August 2019, four environmental samples tested positive for VPDV1 from Tondo (Manila) with no genetic linkage found with any known VDPV1, indicating new emergence. Between 13 and 22 August 2019, two environmental samples tested positive for VDPV2 from Tondo (Manila) and Davao City. Both Type-2 samples were found to be genetically linked. As a result, VDPV2 was classified as circulating (cVDPV2).
According to the WHO, VDPVs are rare strains of poliovirus that have genetically mutated from the strain contained in oral polio vaccines (OPV). VDPVs occur on rare occasions in areas with inadequate sanitation: in seriously underimmunized populations an excreted vaccine virus can mutate and cause acute flaccid paralysis (AFP). VDPVs, therefore, pose a risk of reintroduction of poliovirus after polio eradication.
The re-emergence of polio in the Philippines comes as DOH and other partners continue to respond to the ongoing dengue fever and measles outbreaks. According to the latest reports until end of August 2019, there have been 271,480 dengue cases and 1,107 deaths, and 41,024 measles cases and 552 deaths2 .There has also been increasing numbers of diphtheria being reported, with DOH reporting 167 cases and 40 deaths in 2019 compared to 122 cases and 30 deaths in 2018 .