Worldwide, the introduction of WHO-recommended vaccines into national immunization schedules has increased overall since 2016; however, the rate of new vaccine introductions slowed during the COVID-19 pandemic. More than two thirds of the 194 WHO member countries have now individually introduced Hib vaccine (99%), MCV2 (94%), RCV (89%), PCV (78%), and DTPCV4 (72%). In low-income countries, DTPCV4, HepB-BD, and HPV vaccine are the most underutilized vaccines, whereas in high-income countries, RV vaccine is the most underutilized vaccine. Enhanced efforts are needed to revitalize national vaccine introductions and prioritize equitable access to all vaccines, including those provided beyond infancy, through adolescence, and across the life-course.
A reliable supply of affordable vaccines is required to facilitate new vaccine introductions and achieve high vaccination coverage to achieve the goals outlined in the IA2030, which include achieving at least 500 cumulative vaccine introductions in low- and middle-income countries by 2030; as of 2021, 167 cumulative vaccine introductions had been achieved. During the last 5 years, availability of RV and HPV vaccines has suffered from supply constraints, which have affected vaccine introductions; these constraints have been exacerbated by the COVID-19 pandemic.[4,6] Global partners including Gavi, the Vaccine Alliance, have been working to address challenges around supply and affordability so that the growing portfolio of newly licensed vaccines can be introduced worldwide more rapidly.
In 2016, Gavi began providing support for the national scale-up of HPV vaccine introductions in low- and middle-income countries after small-scale subnational demonstration projects during 2011–2015 determined that introduction was feasible. Despite vaccine supply challenges, the percentage of countries that had introduced HPV vaccine into national programs during 2016–2021 increased by 65%, which is more than the global increase in introductions for any other vaccine. Fifty-seven low- and middle-income countries qualified for Gavi support during 2016–2021, but this support was limited to low- and lower-middle-income countries. Among middle-income countries, which can be further subdivided into lower-middle-income and upper-middle-income, no upper-middle-income countries qualified for Gavi support during 2016–2021. As a result of the COVID-19 pandemic, Gavi paused its investment in certain vaccines (such as DTPCV4 and HepB-BD), which hindered progress for those vaccines introductions.[7,8]
The vaccine access challenges in middle-income countries and the need for increased action have been subjects of increasing focus. Middle-income countries still report that the cost of vaccines is a major obstacle to their introduction, in part because of a lack of procurement capacity and suboptimal in-country regulatory processes. In December 2020, Gavi approved a new approach to engaging with middle-income countries that were formerly Gavi-eligible and selected countries that have never been Gavi-eligible to drive the sustainable introduction of important vaccines that have not yet been introduced, including HPV and RV vaccines. In addition, in 2022, WHO recommended that HPV vaccination may optionally be delivered as a single dose vaccine, which will likely increase programmatic feasibility and flexibility and reduce cost. These efforts to improve targeted donor funding and timely evidence-based updates to global vaccination policy are critical to ensuring continued progress in successful new vaccine introductions worldwide.
The delayed introduction of RV vaccine in high-income countries suggests that challenges beyond vaccine cost or interrupted supply, such as the lack of awareness among policymakers about the benefits of RV vaccine against the impact of rotavirus-related disease, and the lasting negative impact of safety concerns are affecting introductions. Given the evidence that the benefits of RV vaccine far exceed the risks in low-, middle-, and high-income countries, high-level advocacy is needed globally to encourage the prioritization of RV vaccine and other underutilized vaccines. Additions to the evidence base supporting safety and effectiveness of these vaccines in specific contexts can further drive demand and support for these vaccine introductions into country routine immunization schedules. To accelerate global access to DTPCV4 and HepB-BD, targeted funding to support introductions, innovative strategies to address country awareness, and logistical support (e.g., trained staff members and cold chain management) to ensure timely access to vaccination, are needed.[9,10]
The findings in this report are subject to at least three limitations. First, routine immunization schedule data reported by countries to WHO and UNICEF might not reflect national availability of vaccine. Second, incomplete data reported for some vaccines (e.g., DTPCV4 for years 2012, 2013, 2015, and 2016) limited the accuracy of the annual number of vaccine introductions for these years. Finally, World Bank income classification was not available for all countries, so alternative data sources or alternative years were used in calculations.
Implications for Public Health Practice
It is encouraging that, despite the disruptions to essential health services during the COVID-19 pandemic, many countries continued to introduce vaccines into their national schedules during 2020–2021. However, the COVID-19 pandemic slowed progress, and urgent recovery actions are needed. The COVID-19 vaccination response during the pandemic has highlighted the importance of building strong vaccination delivery platforms through childhood and across the life-course. To achieve IA2030 targets, increased efforts to accelerate introductions of new and underutilized vaccines are urgently needed to facilitate equitable access, including access to vaccines delivered beyond the first year of life.
Morbidity and Mortality Weekly Report. 2023;72(27):746-750. © 2023 Centers for Disease Control and Prevention (CDC)