PESHAWAR: Despite a resurgence of polio cases in 2024, Pakistan has achieved significant progress in reversing the epidemiological trends of the crippling virus by reducing its genetic diversity.
“The number of circulating poliovirus variants have been successfully reduced from 12 in 2020 to just two, marking a major milestone in the country’s fight against polio”.
Zia-ur-Rehman, Spokesperson for the Pakistan Polio Eradication Programme, told the Associated Press of Pakistan (APP).
He stated that “In 2020, we had 12 genetic clusters of the poliovirus. Through relentless efforts, we have eradicated ten of them, leaving only two variants in circulation.”
The two remaining variants, YB3A4A and YB3A4B, belonging to the Wild Poliovirus Type 1 (WPV1) strain are the only two surfacing in environmental samples across the country.
Pakistan and Afghanistan have remained the only two countries where WPV1 is endemic, sharing a long, porous border and highly mobile populations, making them a single epidemiological block. In a recent development in 2023, YB3C, an indigenous poliovirus of the region has been eradicated from the country.
Zia confirmed that this variant had not been detected in environmental samples collected from 88 districts over the past 15 months.
Among the six WPV1-infected cases and 126 WPV1-positive Environmental Sampling reported in 2023, nine belonged to groups of viruses derived from the YB3C cluster which has now been eradicated.
“This is a commendable success in our ongoing battle against polio, indicating that the disease is on its last legs,” Zia remarked.
Achieving complete eradication will require comprehensive vaccination coverage and continued public cooperation, he observed.
The progress has received acknowledgment by the Technical Advisory Group (TAG) during its recent meeting held in Islamabad on January 26, 2025.
The meeting, convened by Dr Hanan Balkhy, WHO Regional Director for the Eastern Mediterranean, highlighted the reduction in genetic clusters as a testament to Pakistan’s strengthened vaccination efforts and enhanced virus surveillance network.
The reduction in genetic clusters of poliovirus is attributed to extensive vaccination in the country and increasing virus surveillance network.
The Environmental Surveillance Network has been enhanced from 63 Sewage Collection sites to 127 set up in 88 districts covering almost all the polio endemic areas of the country, Zia added.
“Out of the 155 districts of Pakistan, environmental sampling is being carried out in around 88 districts, covering about 71 percent of the population”, he added.
The quality and coverage of vaccination campaigns have improved, contributing to higher immunity levels among children. In many areas, the virus is detected in sewage samples but does not result in reported infections, underscoring the effectiveness of vaccination efforts.
“To interrupt WPV1 virus transmission, sustained political commitment to polio eradication, including increased accountability at all levels, would be vital for the polio program”, he opined.
Efforts to systematically track and vaccinate children who are missed during polio vaccination activities should be enhanced by better addressing operational issues and the underlying reasons for community resistance to vaccination and vaccine hesitancy.
In the Technical Advisory Group meeting, it was also suggested to improve the vaccination campaign to reach the children who continue to be missed.
Other recommendations included improving the morale and motivation of frontline workers, expanding routine immunization coverage through the EPI, and leveraging the Big Catch-Up campaigns to address gaps in immunization.
Zia said that the country had a frontline vaccinator team of around 400,000 members who administer polio drops to more than 45.4 million children up to the age of five years.
“While polio infections have surged in 2024, the reduction in the virus’s genetic diversity is a positive sign that eradication is within reach,” he added.