MANILA — The World Health Organization has raised concerns with the declaration of a polio outbreak in the Philippines. The country has been wild poliovirus-free for nearly two decades.
“We are very concerned that polioviruses are now circulating in Manila, Davao, and Lanao del Sur,” said Rabindra Abeyasinghe, WHO representative in the Philippines.
The U.N. agency is working closely with the Philippines’ Department of Health and UNICEF on surveillance and responding to the outbreak, according to a news release.
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The announcement came after the Department of Health confirmed that a 3-year-old girl from Lanao Del Sur, a province in Mindanao, had tested positive for the virus. The virus was also found from samples taken in Manila’s sewage system, and waterways in Davao.
The outbreak was confirmed to come from circulating vaccine-derived poliovirus type 2, which can cause paralysis. Type 2 was declared eradicated globally in 2015.
While the oral polio vaccine has been deemed safe and effective, it contains a weakened form of the virus to help build a child’s immune response. But even this low dose of the virus can spread in a community with poor sanitation and hygiene, and circulate in populations with poor and low immunization rates. WHO says that the longer the virus circulates, the more changes it undergoes, which, in “rare” instances, could lead to vaccine-derived poliovirus.
The outbreak comes as the country is battling a measles and dengue outbreak.
Early this year, DOH identified vaccine hesitancy as one of the reasons for the measles outbreak in some regions. Data collected at that time — from Jan. 1 to Feb. 9 — showed that of the reported 4,302 cases, 66% had no history of measles vaccination. Of the 70 who died, 79% had no history of vaccination.
One of the contributors to the public’s mistrust in vaccines was the controversy around the vaccine, Dengvaxia. In 2017, DOH suspended dengue vaccination programs in the country after Sanofi Pasteur, the vaccines division of global pharmaceutical company Sanofi, reported that children who received the vaccine, but did not have any previous dengue infection, could be at potential risk of acquiring the disease.
Soon after, news reports started linking the deaths of children to the vaccine. This created hysteria in the country, leaving parents wary of vaccinating their children despite no confirmation of deaths linked to the vaccine to date.
Vaccine hesitancy is one of the contributing factors to the current polio outbreak, WHO’s Abeyasinghe told Devex.
“The Philippines has been at high risk for poliovirus transmission for several years due to a number of factors, one of which is vaccine hesitancy,” he said.
In 2017, Abeyasinghe said coverage for three doses of oral polio vaccine for children below 1-year-old was at 71%, but dropped to 66% in 2018, the lowest in the past five years — one in every three children is not completing the required three doses.
WHO Philippine representative Abeyasinghe said to stop the spread of diseases, at least 95% of children need to be vaccinated in the country.
Other potential contributing factors include weak surveillance system for acute flaccid paralysis, a rare but serious condition affecting the nervous system, which is key to detecting polio; poor sanitation and lack of access to safe water. Gaps in the health system could also have contributed to the situation.
“Lack of human resources, challenges for certain groups to access health services, and vaccine stock outs continue to challenge the immunization programme,” Abeyasinghe said.
All children under 5-years-old should receive the vaccine, “even if they have had it before,” he said.
“Everyone, whether covered by the mass vaccination campaign or not, should ensure that children have received three doses of OPV and one dose of IPV as part of routine childhood immunization,” he added.
Papua New Guinea also experienced a resurgence in polio cases in 2018, after 18 years of being polio-free.
Amelia Christie, CEO of RESULTS Australia, told Devex the polio resurgence in the region shows just how important it is for the health community to remain vigilant and continue to invest in polio eradication efforts.
“We need to really make sure that people are getting the vaccinations they need for polio, but also for other diseases as well that are preventable. And it also shows that we still really need to invest in the … Global Polio Eradication Initiative,” she said.
GPEI is supporting the Philippine government’s response to the outbreak, according to the joint WHO and UNICEF news release.
Lisa Cornish contributed reporting to this story.