The Philippine Department of Health (DOH) reported its first case of polio on Sep 19, 19 years after the nation was declared free of the childhood disease. 19 years ago,
Officials announcing the outbreak said that the disease was “re-emerging,” dealing a blow to the campaign launched back in 1998, to eradicate it after a case was confirmed in a 3-year-old girl from Lanao del Sur, on the southern island of Mindanao, and another suspected case is awaiting confirmation.
UNICEF defined it as “deeply disconcerting” as it was unexpected. The Philippines was not on a list of at-risk countries compiled by the Polio Global Eradication Initiative.
World Health Organization (WHO) Representative in the Philippines, Dr. Rabindra Abeyasinghe said, “We are very concerned that polioviruses are now circulating in Manila, Davao, and Lanao del Sur. WHO and UNICEF are working closely with the Department of Health to strengthen surveillance and swiftly respond to this outbreak. We urge all parents and caregivers of children under 5 years of age to have them vaccinated so that they are protected against polio for life.”
According to WHO, reported cases due to the wild poliovirus had decreased by more than 99% from an estimated 350,000 cases in 1998 to just 33 reported cases in 2018.
Unfortunately, the disease persists in Pakistan and Afghanistan and the rise of new, vaccine-derived strains of polio have mired efforts to rid the world of the disease. In the Philippines, the last known case of wild poliovirus was back in 1993 and the nation was declared wild polio-free in 2000 together with the rest of WHO’s Western Pacific Region.
Before declaring the outbreak, the Department of Health and its partners launched a polio immunization drive in the City of Manila. The department said as part of the regular environmental surveillance, samples were taken from sewage in the capital, Manila, and in waterways in Davao, Mindanao, the country’s third-largest city, and were found to contain poliovirus. The samples were also verified by the US Centers for Disease Control and Prevention and the Japan National Institute for Infectious Diseases. Additional mass polio immunization rounds will be rolled out from October 2019.
The government also said it was formulating a rapid response to the outbreak in coordination with WHO and UNICEF, with a mass polio immunization drive for all children under 5 starting in October.
Philippines Health Secretary Francisco Duque III said in a statement, “We strongly urge parents, health workers, and local governments to fully participate in the synchronized polio vaccination. It is the only way to stop the polio outbreak and to protect your child against this paralyzing disease.”
WHO said that polio is an infectious disease which spreads swiftly. It can cause paralysis and can even be fatal. There is yet no cure for polio so it can only be prevented with multiple doses of polio vaccines.
Duque added, “Aside from immunization, we remind the public to practice good personal hygiene, wash their hands regularly, use toilets, drink safe water, and cook food thoroughly”.
The 3-year-old girl was found to have a vaccine-derived strain of poliovirus type 2, which according to WHO is of particular concern because the wild strain of this virus was eliminated in 2015.
Vaccine-derived polio occurs when live strains of poliovirus that are used in the oral poliovirus vaccine i.e. OPV mutate, spread and, in some rare cases, trigger an outbreak. Mostly the weakened virus dies off but sometimes it can spread in a region with low vaccination coverage.
WHO said, “If a population is not sufficiently immunized, the weakened virus can continue to circulate. The longer it is allowed to survive, the more changes it undergoes. In rare instances, the virus can change to a vaccine-derived poliovirus (VDPV), a form that has regained the ability to cause paralysis. Poorly conducted immunization activities, when too few children have received the required three doses of polio vaccine, leave them susceptible to poliovirus, either from vaccine-derived or wild polioviruses. Full immunization protects them from both forms of the virus”.