World Immunization Week: Strengthening Routine Immunization Coverage in Polio-Endemic Afghanistan and Pakistan

Wrishmeen Sabawoon, MD, PhD, Senior Advisor, General Incorporated Association Liaison

Each year, April 24-30 is celebrated as World Immunization Week. Started in 2012, this initiative began as an opportunity to call for increased recognition and action around the power of vaccines and immunization. At Liaison, we celebrate the tireless efforts of frontline health workers striving to protect our next generation from vaccine-preventable diseases, such as polio.  

Strengthening routine immunization (RI) coverage in polio-endemic settings such as Afghanistan and Pakistan remains a cornerstone of efforts to interrupt transmission of wild poliovirus (Type1) and prevent the emergence and spread of variant poliovirus. From a technical standpoint, achieving and maintaining high population immunity requires the systematic delivery of multiple doses of Oral Polio Vaccine and at least one dose of Inactivated Polio Vaccine through routine services, ensuring both mucosal and humoral immunity.

However, routine immunization coverage in both countries remains below the ≥90% threshold required to achieve herd immunity, according to data from the World Health Organization (see figure). Suboptimal coverage creates immunity gaps, particularly among zero-dose and under-immunized children, enabling sustained fecal–oral transmission in high-density populations with limited access to safe water and sanitation. Robust RI systems are essential to building cohort immunity beyond the episodic gains achieved through supplementary immunization activities. Strengthening core health system components such as cold chain infrastructure, microplanning, surveillance-informed targeting, and integration with primary health care, enhances vaccine delivery, improves equity, and ensures that missed children are consistently reached, especially in hard-to-reach and conflict-affected areas. Without uniformly high RI coverage at the district level, even small pockets of susceptibility can sustain transmission, trigger outbreaks, and facilitate cross-border spread.

Over the past 50 years, vaccines have saved more than 154 million lives globally, with polio vaccines alone preventing an estimated 1.6 million deaths—equivalent to saving more than four lives every hour. This World Immunization Week, we call on donors and national governments to sustain and increase investments in routine immunization systems, particularly in polio-endemic and high-risk countries where cVDPV outbreaks continue to occur. Strengthening RI is not only a technical necessity but a global health imperative.

Now more than ever, reaching every child with life-saving vaccines is essential to prevent a resurgence of polio. Failure to close immunity gaps risks reversing decades of progress and could result in renewed global spread, leading to paralysis among thousands of children. Sustained commitment to immunization is key to securing a polio-free world.

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