PORT MORESBY - After a long morning of organised chaos inside a crowded government compound in Papua New Guinea's capital Port Moresby, hundreds of health workers and volunteers are finally wrangled into teams, issued with instructions, and piled into a fleet of hard-worn four-wheel drives.
As the first of four mass vaccination waves scheduled over October and November begins to push out across the Pacific nation, emergency teams are rolled out in the capital.
The vehicles are loaded up with loud hailers and ice boxes full of oral polio vaccine. Before they head into the surrounding settlements, posters are hastily taped to the windows and doors: ‘Stop Polio in PNG’.
An outbreak of vaccine-derived polio has been playing out across Papua New Guinea since June. It has been something of an embarrassment to the country's leaders, who have put millions of PNG kina into preparing the capital to host world leaders for the Asia-Pacific Economic Cooperation (APEC) summit.
After 30 years of international effort, the ambition of global polio eradication seemed tantalisingly close when it reached a record low of 118 cases last year. But cases are tracking higher than in 2017, with PNG now accounting for 21 of 109 cases reported so far this year.
This outbreak can be blamed on “the steady breakdown of the health system”, Anup Gurung, WHO's acting officer in charge of the polio response, said at a press conference in September.
Circulating vaccine-derived outbreaks of polio occur when a population is seriously under-immunised and the live attenuated virus that replicates inside vaccinated children mutates and escapes into the environment.
There have been 82 such cases recorded globally to date this year compared with 27 cases of wild poliovirus, which is endemic in only three countries—Pakistan, Afghanistan, and Nigeria.
Given the erosion of routine vaccination coverage in PNG, falling as low as 30% in some parts of the country over recent years, this was a situation that experts had long warned was inevitable, Gurung acknowledged.
Just half of PNG's more than eight million people have access to clean water and less than one-fifth to a toilet that disposes of waste in a way that it does not pose a disease risk.
Genetic analysis of stool samples taken from the victims reveals the virus has been circulating undetected for more than two years, Gurung said. “If you have one case, there would be 200, maybe 500,000 people circulating the virus.”