Global Polio Eradication and Pakistan's Place in It

When the World Health Assembly launched the Global Polio Eradication Initiative in 1988, wild poliovirus was paralysing an estimated 350,000 children a year across 125 countries. Today it circulates in two: Pakistan and Afghanistan. That is a reduction of more than 99.9 per cent, and it makes polio the second human disease in history to come within reach of deliberate extinction, after smallpox.

Pakistan therefore occupies an unusual position. The country is not a bystander to the global campaign — it is one of the two places where the campaign will be decided.

What the global initiative actually is

The Global Polio Eradication Initiative (GPEI) is a partnership rather than a single organisation. It is led by national governments together with the World Health Organization, Rotary International, the United States Centers for Disease Control and Prevention, UNICEF, the Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance. In Pakistan this partnership works through government structures — the National Emergency Operations Centre and its provincial counterparts — rather than alongside them. You can see how that machinery is organised on the core team and partners and donors pages.

Three poliovirus types, two already gone

There are three wild poliovirus serotypes. Type 2 was declared eradicated in 2015 and type 3 in 2019. Only wild poliovirus type 1 (WPV1) remains, which is why every case announcement from Pakistan refers specifically to WPV1.

That progress changed how the world vaccinates. Trivalent oral polio vaccine was withdrawn globally in 2016 and replaced with bivalent OPV covering types 1 and 3, with inactivated polio vaccine (IPV) added to routine immunisation to maintain type 2 immunity. Where type 2 variant virus emerges, programmes respond with novel OPV type 2. The polio FAQs explain what each of these vaccines does.

Why the last mile is the hardest

Eradication is unforgiving in a way that control is not. A disease that is 99 per cent gone is still not gone: poliovirus spreads silently, and roughly one infection in two hundred causes paralysis, so a single visible case signals a much larger pool of unseen transmission. Stopping the virus means reaching the children who are hardest to reach — not the easy majority.

In Pakistan those children are concentrated in a small number of places and circumstances: mobile and displaced families, districts in southern Khyber Pakhtunkhwa where insecurity interrupts campaigns, dense low-income neighbourhoods in Karachi and Quetta, and households where a parent has refused the vaccine. The high-risk area page sets out how the programme classifies and prioritises these districts.

Pakistan and Afghanistan as one epidemiological block

The two remaining endemic countries are treated as a single epidemiological block, because the virus does not recognise the border. Families move constantly between Pak-Afghan crossings for work, trade, family and seasonal migration, and genetic sequencing regularly shows virus strains travelling in both directions. The two national programmes therefore synchronise campaign dates and share surveillance data, and Pakistan vaccinates travelling children at around 500 permanent transit points on borders, highways, bus terminals and railway stations.

What it would mean to finish

Certification of a polio-free world would end the need for routine polio vaccination everywhere and remove a permanent threat of re-importation. Modelling by the eradication partnership has consistently found that finishing the job costs far less than living with the disease indefinitely. It would also be the clearest possible demonstration that a coordinated, decades-long public health effort can succeed under genuinely difficult conditions.

For a longer view of how the disease was understood and finally countered, see the history of polio. For where the Pakistani programme stands right now, see polio in Pakistan and the district-wise case tracker.