London School of Hygiene & Tropical Medicine

Vaccinations given in low- and middle-income countries in the last 20 years could prevent 50 million deaths from infectious diseases, according to new research published in eLife.

The study is the largest assessment of the impact of vaccination activities against 10 infectious diseases across 112 countries before the start of the COVID-19 pandemic.

It was carried out by the Vaccine Impact Modelling Consortium (VIMC) – a multinational collaboration of 16 research groups, led by Imperial College and including experts from the London School of Hygiene & Tropical Medicine (LSHTM). It was funded by Gavi, the Vaccine Alliance, and the Bill & Melinda Gates Foundation.

The team say that success is expected to continue, with a further 47 million deaths predicted to be prevented by vaccination given between 2021 and 2030, if progress is sustained. This would mean 97 million deaths in LMICs would be prevented by vaccination occurring between 2000 and 2030. The majority (52 million) of deaths averted would be children under the age of five.

However, the researchers warn that COVID-19 has disrupted vaccine activities and could lead to a decline in coverage.

While the impact caused by the COVID-19 is difficult, the researchers say delays to vaccine activities are likely as health services are disrupted.

The diseases included in this study included measles, hepatitis B, human papillomavirus (HPV), yellow fever, Haemophilus influenzae type b, Streptococcus pneumoniae, rubella, rotavirus, Neisseria meningitidis serogroup A, and Japanese encephalitis.

If vaccination efforts continue as planned until 2030, the team estimate that 47 million deaths from measles would be averted. The next highest was hepatitis B with 29 million deaths averted and HPV was third with 6.6 million deaths averted.

The study builds on previous work and the team have used new and updated models to better understand the uncertainty ranges for many of the pathogens.

The result of this is that future impact has reduced for measles and hepatitis B and impact in general has reduced for yellow fever. In terms of HPV, the impact has increased when the researchers examined impact by birth cohort as the coverage scenario used by the consortium for this publication is more optimistic than its predecessor.

Kaja Abbas, Assistant Professor of Disease Modelling at LSHTM and one of the paper’s author, said: “Vaccines save millions of lives each year especially among children, while also being a cost-effective intervention and improving health equity globally. This research illuminates the value of vaccination in low- and middle-income countries and the urgent need to sustain immunisation programmes, despite the COVID-19 pandemic related disruptions to immunisation services, for saving millions of lives each year.”

Professor Neil Ferguson, from Imperial College London, said: “Vaccine programmes are making an extraordinary impact in low- and middle-income countries around the world. Millions of lives have been saved already, with the majority being children under the age of five. This research shows that we have the opportunity to protect many more people over the next decade from deadly diseases. This should encourage global efforts to support immunisation programmes and not leave populations vulnerable to infectious diseases in the wake of the Covid-19 pandemic.”

Dr. Katy Gaythorpe, Research Lead of the VIMC, said: “Our study demonstrates the staggering effect of immunisation before the pandemic and the long-term benefits of vaccination activities. We also show what the benefits could have been in a world without SARS-CoV-2. It is critical that we continue vaccine efforts against infectious diseases whilst tackling the ongoing threat of COVID-19.”

Publication

Jaspreet Toor et al. Lives saved with vaccination for 10 pathogens across 112 countries in a pre-COVID-19 world. eLife. DOI: 10.7554/eLife.67635