The DOH gives recognition to provinces with zero local transmission for five consecutive years by declaring these provinces malaria free. Each candidate province is assessed based on codified criteria. These include a field visit by central level staff, a report, and assessment of the documentation by TWG. The subnational strategy for malaria elimination has been in practice since 1995 and turned into policy in 2011 with the Administrative Order No. 2011-0019. An update of the procedures is on the works to include requirements and provisions for the declaration of Highly Urbanized Cities (HUCs) and Independent Component Cities (ICCs).
The Philippine Malaria Program Mid-term review 2019 (MTR) shows the progressive shrinking of the malaria map in the Philippines since 2016. The 32 provinces that had been declared as malaria-free by 2016 have increased to 50 in 2018. The remaining 31 are in the various stages of malaria control and elimination. Out of this number, 27 had zero indigenous malaria case, and four (Palawan, Occidental Mindoro, Sultan Kudarat, Sulu) had ongoing local transmission of malaria in 2018.
98% of indigenous cases is seen in Palawan with Southern Palawan as the most endemic. In this part of Palawan, there are four highly endemic municipalities with a total population of 250,000 (2018) and a malaria caseload, which has fluctuated between 3000 and 7000 (API about 20/1000) over the last 5 years. Most of the cases are in school-age children and younger children, which indicates that there must be a large reservoir of asymptomatic infections in adults. Most of the affected persons are indigenous people, who have until a few years ago hardly had any contact with modern health services. Resurgences in these four municipalities in 2015-16 and again in 2018-19 have coincided with unusually low rainfall. The most likely explanation is that the rainfall deficit makes farming in lowland areas difficult, while it is still possible to farm or gather edible crops in the higher, more densely forested ranges, where vector density is higher. This suggests that the key to addressing the malaria problem among these people is in providing alternative sources of livelihood apart from kaingin farming.