Question 1

What is poliomyelitis?

Accepted Answer

Poliomyelitis (polio) is an acute infectious disease caused by poliovirus — an enterovirus transmitted faecal-orally through contaminated water, food or contact. Most infections (95%) are asymptomatic or cause minor illness. Approximately 1 in 200 infections causes irreversible flaccid paralysis — most often of the legs — and a small proportion of paralytic cases die from respiratory failure. There is no cure; polio can only be prevented through vaccination.

Question 2

Is polio really almost eradicated?

Accepted Answer

Yes — wild poliovirus cases have fallen from 350,000 per year in 1988 to fewer than 10 in 2023 — a 99.9% reduction. Wild poliovirus type 2 was certified eradicated in 2015; type 3 in 2019. Only type 1 remains, in Pakistan and Afghanistan. However, vaccine-derived poliovirus (VDPV) — which can emerge from OPV in under-immunised populations — is detected in dozens of countries annually, meaning surveillance and vaccination must continue globally.

Question 3

Why is the "final mile" so difficult?

Accepted Answer

Eliminating wild poliovirus from Pakistan and Afghanistan faces extraordinary challenges: conflict, insecurity preventing vaccinators from reaching remote areas; a small but influential anti-vaccination movement fuelled by conspiracy theories; large mobile populations crossing porous borders; and remote communities with persistently low vaccination coverage. Vaccinators have been killed in the field. The GPEI works with military escorts, religious leaders and local influencers to reach every child.

Question 4

What is vaccine-derived poliovirus?

Accepted Answer

Vaccine-derived poliovirus (VDPV) emerges when the attenuated OPV vaccine virus circulates in under-immunised populations, accumulates mutations and reverts to neurovirulence. Circulating VDPV (cVDPV) outbreaks now occur more commonly than wild poliovirus — particularly in Africa. They are controlled with novel OPV2 (nOPV2) — a genetically modified vaccine with improved genetic stability that is less likely to revert.

Question 5

What are the two types of polio vaccine?

Accepted Answer

OPV (oral polio vaccine) is a live attenuated vaccine given as drops — easy to administer, provides intestinal immunity blocking transmission, and is used in mass campaigns. It can rarely cause vaccine-associated paralytic polio (VAPP) and VDPV. IPV (inactivated polio vaccine) is injectable — cannot cause VAPP or VDPV, provides excellent blood immunity, but does not block intestinal transmission as well. WHO recommends at least one IPV dose in all national routine schedules alongside OPV campaigns.

Question 6

How is polio diagnosed?

Accepted Answer

Poliovirus infection is diagnosed by isolating virus from stool samples (the most sensitive method) or cerebrospinal fluid. All children under 15 with acute flaccid paralysis (AFP) are investigated as potential polio cases — with two stool samples collected within 14 days of paralysis onset. Environmental surveillance (testing sewage) detects poliovirus circulation before paralytic cases occur.

Question 7

What is the GPEI?

Accepted Answer

The Global Polio Eradication Initiative (GPEI), launched in 1988, is the largest and most complex public health programme in history — coordinating WHO, UNICEF, Rotary International, US CDC and the Bill and Melinda Gates Foundation. It has: immunised over 2.5 billion children; trained 20 million volunteers; and reduced wild poliovirus cases by 99.9%. GPEI's investment in surveillance, cold chain, laboratory networks and community engagement has built durable public health infrastructure across LMICs.

Question 8

What happens after polio eradication?

Accepted Answer

After certification of global wild poliovirus eradication, OPV use would be phased out (since it carries a small VAPP risk). IPV would continue for a transition period. Existing stocks of live virus would be contained. The infrastructure built by GPEI — cold chains, surveillance networks, outbreak response capacity — would be repurposed for other priorities (measles, COVID-19, routine immunisation strengthening). Certification requires 3 years without wild poliovirus cases globally.

Question 9

Has the US had polio recently?

Accepted Answer

Yes — in 2022, an unvaccinated adult in Rockland County, New York was paralysed by vaccine-derived poliovirus type 2. Environmental surveillance detected VDPV2 in New York sewage in multiple counties, indicating community circulation. This demonstrated that VDPV can emerge in under-immunised communities in high-income countries, highlighting the importance of maintaining high vaccination coverage everywhere.

Question 10

What is "wild poliovirus type 2 eradication"?

Accepted Answer

Wild poliovirus type 2 was certified globally eradicated in September 2015 — the first poliovirus serotype to be eradicated. All three wild serotypes (1, 2, 3) were initially circulating in 1988. Type 3 was certified eradicated in October 2019. Only type 1 remains. These are historic achievements of public health — second only to smallpox eradication (1980).

Question 11

How does GMJ News cover poliomyelitis?

Accepted Answer

GMJ News tracks GPEI milestones, wild poliovirus and VDPV outbreak reports, novel OPV2 roll-out and vaccination coverage data. Georgia has maintained polio-free status through strong routine immunisation — directly relevant to PHIG's immunisation advocacy and the Georgian Medical Journal's public health reporting.

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