Vaccines are the most effective way of preventing infectious disease and saving lives.

The Expanded Programme on Immunization (EPI), launched by the World Health Organization in 1974 in response to high rates of vaccine-preventable disease worldwide, was a significant milestone in public health. By reaching communities around the world with life-saving vaccines, the programme has contributed to an enormous reduction in preventable diseases.

The EPI helped eliminate smallpox, fight polio and massively reduce child mortality. After 50 years of its existence, an analysis published in The Lancet today show just how far-reaching the impact of the programme has been. This framework estimates deaths averted, years of life saved and years of full health gained for 14 pathogens within the EPI portfolio.

The majority of lives saved are in children younger than five years old. More than 9 billion years of life have been saved since 1974.

The analysis builds upon infectious disease modelling estimates produced by the Vaccine Impact Modelling Consortium (VIMC) and the Global Burden of Disease study (GBD).

Here are five key achievements.

1. Vaccination has saved 154 million lives since 1974

Between 1974 and 2024, 40% of the global reduction in infant mortality is attributable to vaccination (this benefit goes up to 52% in Africa). Improvements in water, sanitation and hygiene, better nutrition and other factors have improved health and reduced the spread of disease since the 1970s, but vaccination has made the biggest single contribution to the prevention of deadly infections.

Where vaccines have been able to stop transmission, vaccination of a critical number of people has protected unvaccinated people too – which is referred to as herd immunity.

2. Vaccination against measles has saved the most lives

Measles is highly contagious – one infected person can spread the virus to 18 other people. Not only can it be fatal, but it can cause lifelong disability in the form of blindness, deafness or intellectual disability.

Over 50 years, vaccines have prevented nearly 94 million deaths from measles and saved 5.7 billion years of life. However there remain challenges in getting measles vaccines out to all those who need them – according to WHO, 22 million children missed their routine first dose of measles vaccine in 2022, compared to 19 million in 2019.

3. In 2024, a child younger than ten years old is 40% more likely to survive to their next birthday compared with a child born 50 years ago.

The majority of lives saved are in children younger than five years old. More than 9 billion years of life have been saved since 1974.

Young children are the most vulnerable to many of the diseases that can be prevented by vaccines. Many of the diseases prevented by the EPI, such as rubella, polio, pertussis, pneumococcal disease and rotavirus, disproportionately affect young children.

4. The protective benefits continue past the age of 50

The benefits to older adults are greatest in African and Eastern Mediterranean regions, however people worldwide are still seeing the benefits of vaccination even at age 50.

5. 10.2 billion years of health have been gained

Vaccination doesn't just save lives, it also prevents the long-term consequences associated with severe disease, especially polio.

For every life saved, 66 years of full health were gained on average, translating to 10.2 billion years of full health gained. This takes into account years of disability caused by disease.

This article is republished from VaccinesWork under a Creative Commons license. Read the original article. VaccinesWork is an award-winning digital platform hosted by Gavi, the Vaccine Alliance covering news, features and explainers from every corner of global health and immunisation.