The specter of polio, a disease once on the brink of global eradication, is looming large yet again as new reports from 2025 reveal troubling spikes in Afghanistan and Pakistan, compounded by global aid disruptions and vaccine skepticism1. For Thai readers, these developments sound an urgent warning: even diseases thought to be “conquered” can return if public health vigilance lapses, offering a stark lesson relevant to Thailand’s ongoing immunization efforts and pandemic preparedness.
Despite decades of international investment and local campaigns, polio has never fully disappeared from the world map. The latest warnings from public health officials center on setbacks in Pakistan and Afghanistan—the last two countries with ongoing wild polio virus transmission2, 3. In 2024, Pakistan saw cases rise dramatically to 74, while Afghanistan reported 24 infections, reflecting both operational disruptions and the persistent barriers to comprehensive vaccination1. Although these numbers are modest compared to the tens of thousands seen in the 1990s, they represent worrying reversals. In 2025, Pakistan has already recorded six cases and Afghanistan one, signaling that the virus still finds vulnerable footholds.
Polio’s continued existence in these countries matters far beyond their borders, as health experts emphasize. Nicholas Enrich, acting assistant administrator for global health at USAID, warned in internal memos that US aid cuts could, if not reversed, trigger as many as 200,000 new cases of paralyzing polio infections each year, with “hundreds of millions of infections overall” in worst-case scenarios1. Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization, echoed these fears, noting that the “sudden cuts to U.S. funding are also affecting efforts to eradicate polio” globally.
The concern is not theoretical: environmental surveillance has already detected wild polio virus in wastewater samples far from its core strongholds, including major cities in Europe4, reflecting the constant risk of international spread in our interconnected world. Even countries such as Canada and the US, considered “polio-free” for decades, are being urged to maintain vigilant vaccination coverage to prevent the virus from resurging amidst mounting vaccine skepticism and declining immunization rates5.
For Thai readers, it is particularly significant to study the roots of this resurgence. In both Pakistan and Afghanistan, a toxic cocktail of vaccine hesitancy, misinformation, logistical hurdles, and political instability has left millions of children underimmunized. In some communities, fears that vaccines cause infertility or represent a Western plot endure, stoked by incidents like the CIA’s use of a vaccination campaign as cover in the hunt for Osama bin Laden in 20111. In others, fatigue over repeated vaccine campaigns, bans on female health workers (particularly in Afghanistan since the 2021 Taliban takeover), and ongoing violence against health staff have created dangerous immunization gaps6.
One poignant example involves Usman Ali, a two-year-old Pakistani boy from Balochistan who contracted polio after his family, fearing vaccine side effects, avoided immunization but asked health workers to falsely mark his finger, a common tactic to bypass scrutiny. His partial paralysis was a direct consequence of this missed vaccination opportunity1. Balochistan and parts of southern Pakistan suffer the lowest immunization rates, with only 84% of children receiving the recommended injectable vaccine in some areas. The oral vaccine—easier to administer but less effective at fully halting transmission—is delivered more widely, but uptake is uneven, especially in remote, transient, or conflict-affected communities.
The Afghanistan story is equally sobering. The Taliban’s August 2024 suspension of house-to-house vaccine campaigns, shifting efforts to mosques, left many families unable to access immunization, especially as travel for women is heavily restricted. This policy reversal reversed hard-won gains and left large segments of the population at risk. “Women are crucial to these campaigns,” one Afghan health official explained, “because in a conservative country like Afghanistan they would be more welcome by families with women and children… Without female workers, many children are simply missed”1.
Thailand is currently considered free from endemic polio, thanks to robust immunization coverage via the Expanded Program on Immunization (EPI), which offers repeated doses of both oral and inactivated poliovirus vaccines to all Thai children7, 8. The last confirmed case of wild polio in Thailand occurred in 1997, a testament to the country’s effective public health system and high vaccine acceptance. Routine coverage for polio vaccination among Thai children remains above 95%—well above the 80% threshold generally considered necessary for herd immunity in moderate-risk countries, though some experts argue that areas with high population density and limited sanitation, as seen in South Asia, require even higher rates1.
However, the current resurgence in Pakistan and Afghanistan has clear implications for Thailand. First, imported cases are always a possibility due to international travel, labor migration, and cross-border population flows. In 2022, Africa experienced new outbreaks of vaccine-derived polio linked to gaps in immunization amidst COVID-19 disruptions—reminding even “safe” countries that vigilance cannot lapse2, 3. Second, Thailand’s own experience with vaccine hesitancy—rising during the COVID-19 vaccine rollout—shows how quickly public trust can erode in the face of rumors or misinformation9.
Thailand’s diverse population includes migrant workers from neighboring countries, some of which have lower vaccination coverage and experience occasional outbreaks of vaccine-derived polio. In recent years, Thai health authorities have instituted catch-up campaigns targeting these vulnerable groups, including free vaccinations for children of migrants and stateless persons. Maintaining these initiatives is crucial, as gaps can quickly undermine Thailand’s disease-free status.
In the broader context, the polio resurgence also highlights the interconnectedness of public health. As Dr. Hamid Jafari of the WHO polio program explained, “Polio is an epidemic-prone disease. That means that if you don’t interrupt transmission, it resurges after every few years.” Unlike diseases such as smallpox, where eradication has been achieved and maintained, polio’s capacity for silent transmission via asymptomatic carriers and its resilience in low-sanitation environments create perpetual risk1.
Health specialists stress that rumblings of polio’s return coincide with other worrying global vaccination trends. Measles outbreaks have surged in Europe and the Americas as parents skip vital shots, and there is mounting concern that smallpox, once thought vanquished, could theoretically reappear if immunization rates for related diseases plunge5, 10. “This is a wake-up call for Europe,” wrote The Irish Times in response to new polio virus detections in city sewage, noting that “any gaps in vaccination coverage could see a resurgence of the disease”4.
Thailand can draw on its own public health strengths to avoid a similar fate. Comprehensive, sustained education is essential—community engagement must be prioritized, particularly among underserved and marginalized populations. As seen in the aforementioned outbreaks, addressing vaccine fatigue, combating misinformation via trusted local voices (including religious leaders and respected elders), and ensuring that health workers reach the most isolated communities all play vital roles.
The links between global funding and polio control, as highlighted by USAID’s abrupt aid cuts, underscore the need for Thai policymakers to ensure strong, independent public health financing rather than relying exclusively on international partners. Thailand’s history of successful mass immunization depends on political commitment—just as Thai proverb says, “กันไว้ดีกว่าแก้” (Prevention is better than cure).
Looking to the future, vigilance is key. Surveillance for acute flaccid paralysis—an early warning sign of polio—should be maintained and improved. Sewage monitoring, which detected the virus in Europe before clinical cases appeared, could be expanded in high-risk urban Thai areas. Special focus should remain on border regions, migrant worker populations, and areas with historically lower vaccine uptake.
Finally, Thai parents and guardians play the most critical role: ensuring that all children, whether Thai or non-Thai, receive the full course of polio immunizations and periodic boosters as recommended by the Ministry of Public Health7. For adults travelling to at-risk countries, checking one’s own vaccine status and obtaining booster shots for polio is a prudent precaution.
In summary, the world’s unfinished struggle with polio is a lesson in the necessity of public health vigilance—one with direct relevance for Thailand. As Dr. Jafari put it, “This is like sitting on the top of a volcano. This can erupt anytime.” The practical recommendation for Thai readers: double-check your children’s vaccination records, stay informed about emerging health risks, and never take collective immunity for granted. หากวางใจเกินไป อาจต้องย้อนกลับไปยุคที่โรคร้ายแรงเช่นโปลิโอทำให้เกิดความเจ็บปวดอย่างกว้างขวาง—อย่าปล่อยให้ประวัติศาสตร์ซ้ำรอย.
Sources:
- NPR: Could polio be poised for a comeback?
- GPEI: Polio this week
- WHO: Polio Emergency Committee statement April 2025
- Irish Times: Polio virus in European wastewater
- MSN/Global News: Will vaccine skepticism bring polio back?
- PubMed: Polio outbreak in Pakistan
- WHO Thailand: Routine Immunization Schedule
- PMC: Thailand polio eradication strategies
- Bangkok Post: Vaccine hesitancy in Thailand still rage
- OregonLive: Smallpox and declining vaccine rates