UNIVERSITY PARK, Pa. — Vaccine programs in low- and middle-income countries have prevented 37 million deaths in the last 20 years – 36 million of which have been in children under age five.
These are the findings, published Jan. 28 in The Lancet, of the most comprehensive study of the impact of vaccination programs ever undertaken.
“At a time when the whole world is captivated by the development of COVID-19 vaccines, this work is a powerful reminder of the enormous impact that vaccines have had on improving human health,” said Matthew Ferrari, an associate professor of biology at Penn State and a co-author on the paper. “Further, it highlights how much more can be achieved by improving access to vaccines around the world.”
The research, led by an international consortium, suggests the success will continue, with a further 32 million deaths (of which 28 million are deaths prevented in children under age 5) predicted to be prevented by vaccination programs by 2030, if the programs are sustained.
“Vaccines have been one of the most effective public health tools in preventing disease and death,” said Ferrari. “This work quantifies the magnitude of that impact over the last 20 years, and ahead for the next 10.”
According to the researchers, infectious diseases are a major cause of disease and deaths, especially in low- and middle-income countries. Vaccination is one of the most cost-effective health interventions available. Childhood vaccination programs have increased over the last two decades globally, substantially reducing illness and deaths from diseases such as measles, meningitis and hepatitis. This study offers the most reliable estimates of the impact of childhood vaccinations on mortality yet undertaken.
The Vaccine Impact Modelling Consortium, a multinational collaboration of 16 research groups, generated estimates from at least two independent models, for each of 10 diseases: hepatitis B, Haemophilus influenzae type b (Hib), human papillomavirus (HPV), Japanese encephalitis, measles, meningitis A (Neisseria meningitidis serogroup A), pneumococcal disease (Streptococcus pneumoniae), rotavirus, rubella and yellow fever. The team’s estimates focused on deaths averted by vaccination against these diseases in 98 low-and middle-income countries, comprising more than two-thirds of the world’s population, during the period 2000-30.
Ferrari led the development of one of the models of the impact of measles vaccination and conducted projections using that model. He and his colleagues found that the measles vaccination had the largest estimated overall impact, with 33 million estimated deaths prevented in the period 2000-19, equating to more than 1.6 million deaths averted per year. The researchers anticipate this will increase to more than 2.1 million deaths averted per year in future years (2020-30).
The largest potential additional gains will be seen by increasing human papillomavirus (HPV) vaccination coverage in girls. This is predicted to avert more deaths per person vaccinated than any other immunization activity. Increasing pneumococcal conjugate vaccine coverage will give the largest reductions in mortality among children under age 5.
In addition, the findings have implications for the COVID-19 pandemic.
“Highlighting the prior successes of vaccines is an important motivator for our efforts to encourage full vaccination with the COVID-19 vaccines,” said Ferrari. “And recognizing the challenges in achieving full vaccination in other diseases is important to understanding and tackling the challenges that may lie ahead for COVID-19.”
The Vaccine Impact Modelling Consortium is funded by Gavi, the Vaccine Alliance, and the Bill & Melinda Gates Foundation. The views expressed are those of the authors and not necessarily those of the consortium or its funders. The final decision on the content of the publication was taken by the authors. We acknowledge funding the MRC Centre for Global Infectious Disease Analysis (reference MR/R015600/1), jointly funded by the U.K. Medical Research Council (MRC) and the U.K. Foreign, Commonwealth & Development Office (FCDO), under the MRC/FCDO Concordat agreement and also is part of the EDCTP2 program supported by the European Union.