Millions of children’s lives saved by vaccinations against 10 diseases – study
By Nina Massey
From 2000 to 2030 vaccination against 10 major diseases, including measles, HPV and hepatitis B, will have prevented 69 million deaths in low-income and middle-income countries (LMICs), according to new research.
The greatest impact of vaccination was estimated to occur in children under five.
Researchers suggest mortality from the 10 diseases in this age group would be 45% higher than currently observed in the absence of vaccination.
Published in The Lancet, the study estimates vaccinations have prevented 37 million deaths from 2000 to 2019.
Most of this impact is estimated to be among children younger than five, most notably from measles vaccinations.
Dr Caroline Trotter from the University of Cambridge, and a co-author on the study, said: “There has been a much-needed investment in childhood vaccination programmes in low-income and middle-income countries (LMICs) and this has led to an increase in the number of children vaccinated.
“To inform future investment and ensure it continues we need to evaluate the impact of these programmes on public health.
“Our modelling has provided robust evidence on the effectiveness of vaccination programmes in LMICs and indicated what might be lost if current vaccination programmes are not sustained.”
The study involved 16 independent research groups modelling the impact of childhood vaccination programmes in 98 LMICs.
It assessed the impact of vaccination programmes against ten pathogens – hepatitis B (HepB), Haemophilus influenzae type b (Hib), human papillomavirus (HPV), Japanese encephalitis (JE), measles, Neisseria meningitidis serogroup A (MenA), Streptococcus pneumoniae, rotavirus, rubella virus and yellow fever virus (YF).
Multiple models were applied for each pathogen and estimates of impact were based on past and future coverage of individual vaccines, vaccine effectiveness and data on deaths caused by the diseases.
They were also based on years of healthy life lost due to premature death and disability from the diseases (DALYs).
To estimate the impact on deaths and on DALYs, researchers compared a scenario with no vaccination programmes in place to scenarios when vaccinations programmes had been implemented.
The study used two methods to assess impact to provide both a cross-sectional (yearly) and longer-term (lifetime) view of impact.
The first method assessed the difference in the number of deaths between the vaccination and no vaccination scenarios for each year and then totalled these annual results.
The second method assessed the long-term impact of vaccination by summarising impact over the lifetime for groups of people who were born in the same year between 2000 and 2030 and then calculated the difference between vaccination and no vaccination scenarios.
According to the results, between 2000 and 2019 there was an increase in the average number of vaccines received per child, both for existing vaccines such as measles, and for new vaccines such as rotavirus.
Corresponding author, Professor Neil Ferguson from Imperial College London, said: “Our study signifies the huge public health benefits that can be achieved from vaccination programmes in low-income and middle-income countries.
“By projecting up until 2030 in these 98 countries we have provided insight on where investments in vaccine coverage should be directed to achieve further gains, for example increasing HPV coverage in girls and pneumococcal conjugate vaccines (PCV) coverage in children under five will have the most impact according to our modelling.”