Every year UNICEF and the World Health Organization (WHO) produce a new round of immunization coverage estimates for 195 countries, enabling a critical assessment of how well we are doing in reaching every child with life-saving vaccines. Such data help spotlight where progress is lacking, including where reversals in immunization coverage are happening, and where there are areas of success. Both pieces of information are instrumental to monitoring progress towards global frameworks such as the Global Vaccine Action Plan, the Sustainable Development Goals, and the next Immunization Agenda 2030 (IA2030), and for triggering investigations into why immunization coverage is increasing or decreasing in different countries. Further research in countries where immunization coverage has stagnated or regressed makes it possible for partners to work together to address identified bottlenecks to universal coverage. In addition, examination of the factors contributing to observed increases in coverage in specific contexts can provide lessons for other countries as they scale up and improve their immunization programmes.
On 13 March 2020, the novel coronavirus disease COVID-19 was declared a global pandemic, triggering the declaration of national emergencies in many countries as they mounted their responses to the public health threat. By May, data collected by WHO, UNICEF, the U.S. Centers for Disease Control and Prevention (CDC), Gavi and the Sabin Boost Initiative showed that country lockdown measures had substantially hindered the delivery of immunization services in at least 68 countries, putting approximately 80 million children under the age of 1 living in these countries at increased risk of contracting vaccine-preventable diseases.
Understanding the severity and potential deleterious consequences of immunization service disruptions due to COVID-19, including the possible resurgence of measles outbreaks, requires taking stock of trends in immunization coverage prior to the pandemic. This stocktaking includes examining global trends, regional patterns, and variations across countries. Such baseline information provides the needed backdrop for tackling the risk that COVID-19 will turn back the clock on the success of immunization programmes around the world.