Minding the Gap in Global Immunization Coverage

New data released from the World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) show notable declines in key indicators of immunization coverage worldwide over the first year of the Covid-19 pandemic. The coverage decreases reflected in the WHO-UNICEF Estimates of National Immunization Coverage (WUENIC) are significant because even before the pandemic, immunization coverage numbers had plateaued or even declined in some places due to large annual birth cohorts as well as the challenge of reaching children living in informal urban settlements or communities isolated due to natural disasters or conflict.

The expanding gap between the vaccinated and unvaccinated worldwide means that more children than before are vulnerable to deadly and debilitating diseases, such as diphtheria, tetanus, pertussis, and measles, which can lead to costly outbreaks. While some recent analysis suggests that the losses in immunization coverage were most significant during the pandemic’s early months, with many countries able to recover some losses in the second half of 2020, countries that were already struggling in the pre-pandemic period will need resources and technical assistance to “catch up.” The WUENIC data underscore the importance of sustaining attention on routine immunization services globally while ensuring countries are ready to deliver Covid-19 vaccines once they are available.

Q1: What do the new WUENIC data show?

A1: Every year, in the middle of July, the WHO and UNICEF release updated estimates of national immunization coverage, based on information reported from member countries. The new data show that in 2020 at least 23 million children worldwide missed receiving at least one of three recommended doses of combined diphtheria-tetanus-pertussis (DTP) vaccines, generally administered in a child’s first year. Because the schedule requires families to bring infants to health clinics for the three doses, the coverage rates serve as a likely indicator of access to other vaccines and as a more general proxy for very young children’s access to the health system. In this context, it is particularly concerning that an estimated 17 million children missed the first—and presumably all—recommended DTP doses last year. Even before the pandemic, reaching these “zero-dose” children had been a cornerstone of the 2021–2025 strategy of Gavi, the Vaccine Alliance, a public-private partnership that supports lower-income countries’ efforts to extend immunization services, including new vaccines, to their populations. Reaching even more unvaccinated children with their first shots while ensuring others have the complete set of vaccines means mobilizing greater financing, technical assistance, and program support, a challenge in a disruptive global pandemic.

Q2: Where are the challenges most significant?

A2: The new WUENIC data show that countries in all regions experienced decreases in the number of children accessing DTP vaccines in 2020. However, 60 percent of the children who missed the first dose were in just 10 countries, with the greatest decreases in coverage from 2019 to 2020 reported in India, Pakistan, and Indonesia. The Americas, where the pandemic has had an especially negative impact, also saw regional coverage of all three DTP doses fall to 82 percent, with large increases in the number of children missing the first DTP dose in Mexico, Argentina, and Venezuela. Mozambique, Angola, Tanzania, and Mali in sub-Saharan Africa were also among the 10 countries with the largest increases in zero-dose children. During the pandemic, the closure of health facilities during lockdowns, the diversion of health workers and resources to outbreak response, and parents’ unwillingness to bring children to clinics out of fear of their being exposed to infection with SARS-CoV-2, the virus that causes Covid-19, have all limited children’s access to immunizations. At the same time, the circulation of misinformation about vaccines undermines some families’ confidence in the products and leads parents to delay or skip their children’s recommended doses.

Q3: Why should the United States be concerned about middle-income countries?

A3: Although 90 percent of all countries reported stagnation or lower DTP coverage than in 2019, populous middle-income countries are among those reporting the greatest decreases in 2020. Unlike lower-income countries, which are eligible for access to reduced vaccine prices and funding for immunization and health systems strengthening from Gavi, countries classified as middle-income have annual gross national incomes per capita that exceed the Gavi eligibility threshold and face challenges purchasing and distributing vaccines. In the Americas, where most countries are classified as middle income, the Pan American Health Organization (PAHO), the regional arm of the WHO, does negotiate low prices for vaccines for member states by pooling demand and procurement through its Revolving Fund. However, the decreases in immunization coverage in several countries in the region, where the numbers had already been declining in recent years, suggest that for middle-income countries struggling to maintain coverage, product pricing and supply is just one factor; the availability of trained health workers, adequate vaccine storage capacity, efficient delivery systems, and the population’s confidence in vaccines are important elements as well. Even before the pandemic, Gavi had begun exploring ways to support middle-income countries with technical assistance, and the new WUENIC data add to the argument for sustaining multilateral and bilateral efforts to strengthen middle-income countries’ immunization programs. 

Q4: What do the WUENIC data mean for Covid-19 vaccine introductions?

A4: To a great extent, the strength and resilience of countries’ routine immunization programs will help determine their preparedness to deliver the Covid-19 vaccines once they are widely available. At the same time, it is important to remember that programs that deliver routine immunizations are focused on reaching infants and children, whereas the Covid-19 vaccines are intended for older populations and will require engaging a different set of health workers as well as the use of adult-focused health facilities for delivery. The WUENIC data also underscore the importance of sustaining support for routine and child-centered programs to prevent further expansion of the coverage gaps while supporting country preparedness to introduce Covid-19 vaccines. As Covid-19 vaccines become more widely available worldwide, reaching adults with the products will offer opportunities for health workers to deliver messages about the importance of immunizations and health services for all ages.

Q5: How can the United States support routine immunization efforts globally?

A5: Supporting countries’ routine immunization efforts is already an important element of U.S. global health security and development strategies. The United States has long been a supporter of Gavi, the Vaccine Alliance, and provides bilateral support for immunization programs through the U.S. Agency for International Development (USAID) and the U.S. Centers for Disease Control and Prevention (CDC). It is also supporting COVAX, the vaccine pillar of the global Access to Covid-19 Tools Accelerator (ACT-A), through the commitment of $4 billion to Gavi for the procurement and delivery of Covid-19 vaccines to the 92 low-income countries that are participating in the COVAX Advance Market Commitment (AMC),  which facilitates access to financing for Covid-19 vaccine purchases. The United States has endorsed the new global Immunization Agenda 2030 (IA2030) and committed to the key elements of that ambitious plan to ensure equitable access to vaccines across the life course. The CDC’s Global Immunization Strategic Framework 2021–2030 outlines five key goals to support countries’ immunization efforts over the next 10 years.

Looking ahead, the United States can ensure coordination and alignment on routine immunization activities among the diverse agencies involved in supporting global efforts; pursue opportunities to support middle-income countries’ routine immunization efforts; and ensure that planning, funding, and assistance for global Covid-19 vaccine efforts complement and build on existing immunization programs to strengthen the delivery of vaccines to infants and children and advance global health security.

Katherine E. Bliss is a senior fellow with the Global Health Policy Center at the Center for Strategic and International Studies in Washington, D.C.

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Katherine E. Bliss
Senior Fellow and Director, Immunizations and Health Systems Resilience, Global Health Policy Center