We know that vaccines have been a miracle for public health. Now, new research led by the World Health Organization (WHO) has found that vaccines for 14 different diseases have saved an estimated 154 million lives over the past 50 years. Most have been in children under 5 years old and regarding two-thirds in children under 1 year old.
In 1974, the World Health Assembly launched the Expanded Program on Immunization with the goal of vaccinating all children once morest diphtheria, tetanus, pertussis (whooping cough), measles, polio, tuberculosis and smallpox by 1990.
The program was later expanded to include other diseases.
The modelling, which marks 50 years since this programme was established, shows that a child under the age of 10 is almost 40% more likely to reach their next birthday compared to what would happen if we did not have vaccines.
And these positive effects can be seen well into adulthood.
A person over 50 years old is 16% more likely to celebrate their next birthday thanks to vaccines.
What the study showed
The researchers developed mathematical and statistical models into which they entered data from the Vaccine coverage and population figures for 194 countries from 1974 to 2024Not all diseases were included (for example, smallpox, which was eradicated in 1980, was excluded).
The analysis includes vaccines for 14 diseases, 11 of which were included in the Expanded Program on Immunization.
For some countries, additional vaccines such as those for Japanese encephalitis, meningitis A and yellow fever were included, as these diseases contribute to a serious burden of disorders in certain settings.
The models were used to simulate the spread of diseases from 1974 until now.as vaccines were introduced, for each country and age group, incorporating data with increasing vaccine coverage over time.
Children are the greatest beneficiaries of vaccines.
Since 1974, infant mortality rates before their first birthday have been reduced by more than half. Researchers calculated that Almost 40% of this reduction is due to vaccines.
The effects have been greatest in children born in the 1980s because of intensive efforts globally to reduce the burden of diseases such as measles, polio and whooping cough.
60% of the 154 million lives saved would have been lost to measlesThis is probably due to the disease’s ability to spread rapidly. A person with measles can infect 12 to 18 people.
The study also found some variations in different parts of the world.
For example, vaccination programmes have had a greater impact on life prospects in low- and middle-income countries and in settings with weaker health systems such as in the Eastern Mediterranean and African regions.
These results highlight The important role that vaccines play in health equity.
The success of vaccines is not guaranteed
Low or declining vaccination coverage can result in epidemics that can devastate communities and overwhelm health systems.
The Covid pandemic, in particular, saw an overall reduction in measles vaccination coverage: from 86% of children who had received their first dose in 2019 to 83% in 2022.
This is worrying because high levels of vaccination coverage (more than 95%) are needed to achieve the herd immunity once morest measles.
In Australia, childhood vaccination coverage, including once morest measles, mumps and rubella, has declined compared to pre-pandemic figures.
This study is a reminder of why we need to continue vaccinating, not just once morest measles, but once morest all diseases for which we have safe and effective vaccines.
The results of this research do not tell us the whole story of the impact of vaccines.
For example, the authors did not include data on some vaccines such as those for COVID or HPV (human papillomavirus).
Furthermore, as in all modeling studies, There are some uncertaintiessince data is not available for all periods and countries.
However, the results show the global success of vaccination programs over time.
If we want to continue to see lives saved, we need to continue investing in vaccinations at local, regional and global levels.
*Meru Sheel is an Adjunct Professor and Epidemiologist in the Infectious Diseases, Immunisation and Emergencies Group at the School of Public Health at the University of Sydney; Alexandra Hogan is a mathematical epidemiologist at the University of New South Wales, Sydney.
His article was published in The Conversation, which we reproduce under the Creative Commons license and whose original version in English you can find read here.
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