Estimating the health impact of vaccination against 10 pathogens in 98 low and middle income countries from 2000 to 2030
Authors: Li Xiang , Mukandavire Christinah , Cucunubá Zulma M , Abbas Kaja , Clapham Hannah E , Jit Mark , Johnson Hope L , Papadopoulos Timos , Vynnycky Emilia , Brisson Marc , Carter Emily D , Clark Andrew , de Villiers Margaret J , Eilertson Kirsten , Ferrari Matthew J , Gamkrelidze Ivane , Gaythorpe Katy , Grassly Nicholas C , Hallett Timothy B , Jackson Michael L , Jean Kévin , Karachaliou Andromachi , Klepac Petra , Lessler Justin , Li Xi , Moore Sean M , Nayagam Shevanthi , Nguyen Duy Manh , Razavi Homie , Razavi-Shearer Devin , Resch Stephen , Sanderson Colin , Sweet Steven , Sy Stephen , Tam Yvonne , Tanvir Hira , Tran Quan Minh , Trotter Caroline L , Truelove Shaun , van Zandvoort Kevin , Verguet Stéphane , Walker Neff , Winter Amy , Ferguson Neil M ,   Tini Garske (Vaccine Impact Modelling Consortium)
Published: August 2019

Background

The last two decades have seen substantial expansion of childhood vaccination programmes in low and middle income countries (LMICs). Here we quantify the health impact of these programmes by estimating the deaths and disability-adjusted life years (DALYs) averted by vaccination with ten antigens in 98 LMICs between 2000 and 2030.

Methods

Independent research groups provided model-based disease burden estimates under a range of vaccination coverage scenarios for 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, yellow fever. Using standardized demographic data and vaccine coverage estimates for routine and supplementary immunization activities, the impact of vaccination programmes on deaths and DALYs was determined by comparing model estimates from the no vaccination counterfactual scenario with those from a default coverage scenario. We present results in two forms: deaths/DALYs averted in a particular calendar year, and in a particular annual birth cohort.

Findings

We estimate that vaccination will have averted 69 (2.5-97.5% quantile range 52-88) million deaths between 2000 and 2030 across the 98 countries and ten pathogens considered, 35 (29-45) million of these between 2000-2018. From 2000-2018, this represents a 44% (36-57%) reduction in deaths due to the ten pathogens relative to the no vaccination counterfactual. Most (96% (93-97%)) of this impact is in under-five age mortality, notably from measles. Over the lifetime of birth cohorts born between 2000 and 2030, we predict that 122 (96-147) million deaths will be averted by vaccination, of which 58 (39-75) and 38 (26-52) million are due to measles and Hepatitis B vaccination, respectively. We estimate that recent increases in vaccine coverage and introductions of additional vaccines will result in a 72% (61-79%) reduction in lifetime mortality caused by these 10 pathogens in the 2018 birth cohort.

Interpretation

Increases in vaccine coverage and the introduction of new vaccines into LMICs over the last two decades have had a major impact in reducing mortality. These public health gains are predicted to increase in coming decades if progress in increasing coverage is sustained.