AFTER measles and dengue, now it’s polio. While so far only two cases of acute flaccid paralysis (AFP) have been attributed to poliovirus, the Department of Health has declared a polio outbreak, in compliance with World Health Organization (WHO) recommendations. Polio, officially eradicated in the Philippines 19 years ago, is a highly infectious disease with no known cure.
Unfortunately, “chronically sub-optimal immunization coverage with polio vaccines, sub-optimal performance of AFP surveillance, and poor sanitation and hygiene conditions” are the factors identified by WHO that have been making and continue to make the Philippines “a high risk for poliovirus transmission in case of importation or emergence and circulation of poliovirus” (Unicef-WHO Philippines Situation Report 1 on Polio Outbreak).
Last year, Papua New Guinea, like the Philippines officially polio-free since 2000, recorded 26 cases of vaccine-derived poliovirus — an early warning of what could happen here as well.
The poliovirus that has been found in environmental samples in Tondo, Manila and the Davao River in Davao City, and which has caused paralysis in a three-year-old girl in Lanao del Sur and a five-year-old boy in Laguna, is vaccine-derived. It is wild poliovirus (type 1), which continues to destroy lives of children in Afghanistan and, in particular, in Pakistan. Sixty-two cases of wild poliovirus infections have been recorded in Pakistan this year.
Another important point to make is that what has been found in the Philippines are vaccine-derived poliovirus of types 1 and 2. The vaccine-derived poliovirus, to be distinguished from the wild virus, is called such because it originated from the weakened form of the virus from the oral polio vaccine. Unicef explains that “the weakened virus replicates in the intestine for a limited period, thereby developing immunity by building up antibodies. During this time, the virus is also excreted [in the feces]. In areas where there is inadequate sanitation and hygiene, the excreted weakened virus can spread in the immediate community before eventually dying out” (Unicef, Sept. 19, 2019).
The type detected in Tondo, Manila is vaccine-derived poliovirus type 1, while it was type 2 that was found in the Davao River and which caused paralysis in the girl in Lanao del Sur. “The polio outbreak in the Philippines is confirmed to be from a circulating vaccine-derived poliovirus 2,” Unicef explains, adding that this “is of particular concern, as wild poliovirus type 2 was certified as globally eradicated in 2015.” Subsequent to the eradication, type 2 was removed from oral polio vaccine (OPV) to avoid vaccine-associated polio.
In the Philippines, routine immunization of young children includes three doses of OPV (covering poliovirus types 1 and 3) and one dose inactivated poliovirus vaccine (IPV) that is injected. IPV protects against all three poliovirus types. Coverage for IPV in particular has been very low — about 50 percent since it was introduced in 2016, and only 23 percent so far this year, according to the Unicef-WHO Philippines Situation Report 1 on the polio outbreak. Ninety-five percent coverage is needed to ensure full protection against polio.
The City Health Office (CHO) of Davao City reported local coverage rates in 2018 as 76.6 percent and 71.7 percent for OPV and IPV, respectively. A CHO worker told Sun Star Davao that a shortage of IPV resulted in a lower IPV immunization rate. Is shortage of IPV only a problem in Davao City or is it a nationwide situation? This is alarming.
The two environmental samples from the Davao River that came out positive for vaccine-derived poliovirus type 2 were taken near the Bolton Bridge, an area where high fecal coliform levels have previously been found. However, it is not known whether the poliovirus came from upstream or from a more heavily populated area downstream where many households do not have sanitary toilets (Sun Star Davao, September 20). Davao CHO head Josephine Villafuerte has advised the public to avoid swimming in the river and in public swimming pools (Mindanao Times, September 21).
The Philippines has been added to the list of now nine countries with vaccine-derived poliovirus breakouts this year — China recorded one case, Myanmar four, while the other six countries are in Africa. Afghanistan and Pakistan continue to struggle with wild poliovirus. The good news is that polio outbreaks can be managed. There have been no new cases in PNG this year after the 26 recorded cases in 2018 (www.polioeradication.org). This should be a case for hope and inspiration.
Farewell to an outstanding civic leader
Florencio “Poly” Lat, the tall, dark and handsome Filipino who has been crisscrossing the world for Kiwanis International is no more. Poly, incumbent president of the Indianapolis-based service organization, succumbed to cancer on September 18. I knew Poly as a straightforward, down-to-earth, and warm person. I am grateful for the part, however small, that I played in Poly’s rise to the top position in Kiwanis. It was a privilege to know you, Poly.