On September 19, 2019, the Department of Health (DOH) announced a polio outbreak in the country, reporting a confirmed case of vaccine-derived poliovirus type 2 (VDPV2) in a 3-year-old girl in the southern island of Mindanao, as well as environmental samples in Manila and Davao — two of the country’s largest cities — testing positive for poliovirus. A day later, another VDPV2 case was announced, this time in a 5-year old boy in the northern island of Luzon.
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The announcements mark the first official confirmation of polio’s presence in a country declared by the World Health Organization as polio-free in 2000. Coming after recent measles and (a still-ongoing) dengue epidemics, the news of polio’s reemergence adds to the public health challenges in the country.
The possibility that polio could return, however, has been long foreshadowed by persistently low rates of polio immunization, which, as the parallel case of Papua New Guinea demonstrates, can lead to the emergence of mutated vaccine-derived polioviruses. From 2007 to 2017, the coverage rate for the third dose of oral polio (OPV3) ranged from 91% to 72%, and in the wake of the dengue vaccine scandal in 2017, the rate reached an all-time low of 66%. While it is easy to blame the likes of Persida Acosta — who rightfully deserves to be held accountable for her fear-mongering — public health officials need to reflect on what went wrong from a deeper and broader perspective. .
The DOH vows to intensify ‘mass immunization’ and ‘zero defecation’ campaigns — and deserves all the support they need for these initiatives — especially since eliminating polio could be more difficult this time around. As mentioned above, the country is grappling with low rates of immunization coverage. Rapid urbanization and rural neglect have given rise to more communities with poor sanitation and limited access to water, rendering more individuals at risk of acquiring infectious diseases, especially polio which is transmitted via the fecal-oral route. Moreover, the country’s significant overseas population makes polio control in the Philippines especially imbricated in the global flows of infectious diseases (consider that the recent measles outbreaks in the US and Japan were associated with cases from the Philippines).
Globally, the polio outbreak reanimates questions as to whether trivalent OPV (containing strains 1,2, and 3) — which most countries shifted from in 2015-16 in favor of a bivalent vaccine (containing strains 1 and 3) — needs to be restored and whether any global recommendations need to be changed.
As for the Philippines, beyond the immediate concern of guaranteeing vaccine supplies (including monovalent OPV for Type 2 strains and IPV) for vulnerable populations and treating affected individuals, there is a need to reform and strengthen the decades-old ‘Expanded Program of Immunization’ which has been beset with supply chain issues and human resource shortages both at the national and local levels. In a country where health governance is decentralized, the establishment of a National Immunization Technical Advisory Group (NITAG) is essential to set strategic directions, coordinate inter-agency responses, and insulate immunization programs from political quandaries like the one that happened with the dengue vaccine.
Moreover, there is a need to pursue concerted communications efforts to inform the public about vaccines, prevent undue panic (which we already observe to be already happening with adults asking to be vaccinated) and address the sources of vaccine mistrust. Utmost transparency must be shown in the licensing and procurement of vaccines, as well as possible side effects. Without restoring trust in the government (a goal that entails holding officials accountable for both politicized anti-vaccination claims and anomalous vaccine-related actions), the country's immunization program will come short of the 95% coverage required for herd immunity.
Lastly, there is a need to strengthen the country’s health information systems, including the Philippine Integrated Disease Surveillance and Response (PIDSR). Although the new cases definitively indicate polio, the magnitude of the outbreak will only be clear with high rates of reporting from public and private health facilities, as well as greater inter-agency coordination. New pieces of legislation, like the Universal Health Care Law and the Notifiable Disease Law, acknowledge the importance of these imperatives, but their relevant provisions must be properly and urgently implemented.
All of the above will require political commitment, leadership, and accountability — all of which must be fulfilled if we are to finally and definitively eradicate polio in the Philippines and around the world.
John Andrew Camposano is a pediatric infectious disease specialist based in West Visayas State University, Iloilo City. Gideon Lasco (@gideonlasco) is a physician and medical anthropologist.