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In 1974, at the request of member states, the World Health Organization (WHO) launched the Expanded Program on Immunization (EPI) to make life-saving vaccines universally accessible. 

Marking 50 years of the EPI, an analysis using advanced modeling — published in The Lancet — estimated that the program has prevented 154 million deaths since 1974, including 146 million in children under 5 years of age and 101 million in their first year of life. According to the authors, every region of the world has seen substantial improvements in child survival, with EPI making the largest contribution to these improvements over the past 50 years.

Disease Impact

Using mathematical and statistical models, researchers evaluated the global and regional impact of vaccination against diphtheria, Hemophilus influenzae type B, hepatitis B, Japanese encephalitis, measles, meningococcal A, pertussis, pneumococcal disease, polio, rotavirus, rubella, tetanus, tuberculosis, and yellow fever across 194 countries from 1974 to 2024.

This study compared real-world immunization coverage with the results of a hypothetical scenario without vaccines by integrating cohort models, literature reviews, and estimates of the Global Burden of Disease. This approach evaluated both the direct effectiveness on vaccinated subjects and the indirect benefits to the community and the impact on different demographic groups.

Measles vaccines alone have saved 94 million lives, accounting for over 60% of the total. Tetanus and pertussis vaccines have prevented an estimated 28 million and 13 million deaths, respectively. On average, each life saved added 66 years of healthy living. Vaccination drove 40% of the global decline in childhood mortality and up to 52% in Africa. In 2024, a child under 10 years of age has a 40% greater chance of surviving until their next birthday than in a world without historic immunization. An increased probability of survival was also observed in the older age groups.

Program Evolution

After eradicating smallpox in 1980, the WHO launched a global initiative in 1990 with the initial goal of vaccinating all children against tuberculosis, diphtheria, tetanus, pertussis, polio, and measles. 

The EPI has expanded to include more diseases, adapt to country-specific needs, and cover all age groups. The global coverage of the third diphtheria, tetanus, and pertussis dose, a key performance indicator, rose from less than 5% in 1974 to 86% in 2019 (pre-pandemic), and is currently at 84%.

EpiCentro reported that by 24 months of age, vaccine coverage in Italy reached 94.76% for polio, diphtheria, tetanus, and pertussis; 95.1% for H influenzae type B; 94.64% for measles and rubella; 94.61% for mumps; and 93.76% for varicella.

Physicians’ Role

Physicians are key to promoting vaccination, countering vaccine hesitancy, and ensuring timely booster doses. Adequate coverage provides strong individual protection and herd immunity, helping to reduce or stop the spread of pathogens. Many vaccines offer lasting protection, leading to lower rates of severe illness, hospitalizations, and deaths, while easing the burden on health systems.

“In the context of strengthening primary health care, our results show that equitable universal access to immunization remains crucial to sustain health gains and continue to save future lives from preventable infectious mortality,” the authors concluded. 

This story was translated from Univadis Italy.