Immunization is one of the most cost-effective public health interventions to date, averting an estimated 2 to 3 million deaths every year. As a direct result of immunization, the world is closer than ever to eradicating polio, with only two remaining polio endemic countries – Afghanistan and Pakistan. Deaths from measles, a major child killer, declined by 73 per cent worldwide between 2000 and 2018 preventing an estimated 23.2 million deaths. And as of today, all but 12 countries have eliminated maternal and neonatal tetanus, a disease with a fatality rate of 70 to 100 per cent among newborns.
The percentage of children receiving the diphtheria, tetanus and pertussis vaccine (DTP) is often used as an indicator of how well countries are providing routine immunization services. In 2019, global coverage rates for the third dose of the diphtheria, tetanus and pertussis vaccine (DTP3) reached 85 per cent, up from 72 per cent in 2000 and 20 per cent in 1980. Still, progress has stalled over the decade, and 85 countries have yet to achieve the Global Vaccine Action Plan (GVAP) target of 90 per cent or greater coverage of DTP3. [1] In 2019, 19.7 million children under 1 year of age worldwide did not receive the three recommended doses of DTP, and the number of zero-dose children – defined as children in the same age group who did not benefit from any vaccination – was an estimated 13.8 million.
Multiple factors, including conflict, under-investment in national immunization programmes, vaccine stock-outs, and disease outbreaks, contribute to the disruption of health systems and prevent sustainable delivery of vaccination services. Two in five (nearly 8 million) of the un- and under-vaccinated infants live in fragile or humanitarian settings [2], including countries affected by conflict. These children are the most vulnerable to disease outbreaks. In Yemen, for example, children accounted for over 58 per cent of the more than one million people affected by a cholera outbreak or watery diarrhoea in 2017 alone.
In 2019, 6 countries had 50 per cent or less DTP3 coverage – many of which are fragile states or affected by emergencies: Central African Republic, Chad, Guinea, Papua New Guinea, Somalia, and South Sudan. Globally in 2019, half of children unvaccinated for DTP3 lived in just six countries: Brazil, Democratic Republic of the Congo, Ethiopia, India, Nigeria, and Pakistan. Note that populous developing countries contribute significantly to the number of unvaccinated children despite achieving relatively high rates of immunization coverage, as evidenced by India hosting 2.1 million of the under-vaccinated even with 91 per cent coverage of a cohort of approximately 21 million surviving infants. Efforts to raise global immunization levels will require a strong focus on the countries where the highest numbers of unvaccinated children live – while also ensuring that countries where children are most likely to miss out on immunization are not neglected.
Through UNICEF’s joint efforts with partners and countries, vaccines have become safer and more accessible than ever before. The cost of fully immunizing children in low-income countries is just US $18 per child, down from US $24.5 in 2013. An increasing number of countries have fully introduced the pneumococcal conjugate vaccine (145 countries as of 2019) and rotavirus vaccine (105 countries as of 2019) in their immunization programmes, thus offering protection against pneumonia and diarrhoea. Human papillomavirus (HPV) is the most common viral infection of the reproductive tract, and can cause cervical cancer in women. As of 2019, the HPV vaccine was fully introduced in 103 countries. Use of underutilized vaccines, such as those against yellow fever and Japanese encephalitis, has also been expanded. However, while low income countries have largely been able to close coverage gaps with assistance from Gavi, the Vaccine Alliance, vaccine introduction is lagging in middle income countries who struggle to find both national resources and external funding sources.
No child should die from a preventable cause, and all children should be able to reach their full potential in health and well-being. The cost of a vaccine, often less than US $1, is much lower than the cost of treating a sick child or fighting a disease outbreak. Each US $1 invested in childhood vaccination produces a return on investment of US $44 in low- and middle-income countries. More details on the cost and financing of vaccination can be found here.
References
- In 2019, 85 countries have not achieved and sustained DTP3 coverage of 90% for at least three years, i.e. 2017, 2018 and 2019.
- World Bank Fragile and Conflict-affected Situations (FCS), FY 2020
