Temporal decline in diarrhea episodes and mortality in Kiribati children two years following rotavirus vaccine introduction, despite high malnutrition rates: a retrospective review

Jana Lai,Batmunkh Nyambat,Kimberley Fox,Murat Hakan Ozturk,Fiona Russell,Cattram Nguyen,Beia Tabwaia,Nikarawa Baueri,Wendy Erasmus,Tinai Iuta,Stephanie Davis,Eretii Timeon,Agnes Nikuata,Mohammed Diaaldeen,Alice Hall,Ataur Rahman,Aaron Moore

doi:10.1186/s12879-020-4874-6

Abstract

BackgroundKiribati introduced rotavirus vaccine in 2015. To estimate the impact of rotavirus vaccine on acute gastroenteritis (AGE) and severe acute malnutrition (SAM) among children under 5 in Kiribati, a retrospective review of inpatient and outpatient AGE and hospitalized SAM was undertaken.MethodsInpatient data for admissions and hospital deaths due to AGE, SAM and all-causes were collected for children under 5 from all hospitals on the main island, Tarawa, from January 2010–December 2013 (pre-rotavirus vaccine) and January 2016–September 2017 (post-rotavirus vaccine). National outpatient diarrhea data were collected from January 2010 to August 2017 for under 5. An interrupted time-series analysis was undertaken to estimate the effect of rotavirus vaccine on the rates of inpatient and outpatient AGE, inpatient SAM; and inpatient case fatality rates for AGE and SAM, were calculated pre- and post-rotavirus vaccine introduction.ResultsThe incidence rate of AGE admissions from Tarawa and national AGE outpatient presentations significantly declined by 37 and 44%, respectively, 2 years following rotavirus vaccine introduction. There was a significant decline in the percentage of AGE contributing to all-cause under 5 admissions (12·8% vs. 7·2%, p < 0·001) and all-cause under-five mortality (15·9% vs. 5·7%, p = 0·006) pre- and post-rotavirus vaccine introduction. The estimated incidence rate of inpatient SAM decreased by 24% in under 5 s, 2 years following rotavirus vaccine introduction.ConclusionsAGE morbidity and mortality and hospitalized SAM rates have declined following rotavirus vaccine introduction in Kiribati children.

Highlights

The median percentage reduction in acute gastroenteritis (AGE) hospitalizations overall was 38% and for those rotavirus AGE hospitalizations and emergency department visits an overall reduction of 67% were observed [12], with greater vaccine coverage leading to greater reductions [13]
The percentage of AGE contributing to all-cause admissions declined by 43.7% (12.8% vs. 7.2%, p < 0.001), and by 64.2% for allcause mortality (15.9% vs. 5.7%, p = 0.006), postrotavirus vaccine introduction
We found a 64.2% reduction in allcause childhood mortality due to AGE which is much higher than the median reduction of 40% reported in the global review post-rotavirus vaccine introduction, in high child mortality settings [21]

Summary

Introduction

To estimate the impact of rotavirus vaccine on acute gastroenteritis (AGE) and severe acute malnutrition (SAM) among children under 5 in Kiribati, a retrospective review of inpatient and outpatient AGE and hospitalized SAM was undertaken. About one third to half of hospitalized cases of diarrheal illness in under 5 s are associated with rotavirus, with a peak incidence in children 6–24 months old [3, 4]. The effectiveness of rotavirus vaccine in gastroenteritis-related hospitalizations appears to be lower in low-income countries compared with high-income countries (~ 50% vs 98%) [14]. A study from Malawi found that stunted infants less than 12 months old had a non-significant lower vaccine effectiveness compared with their well-nourished counterparts [14]. Understanding the situation of malnutrition is important when assessing the impact of rotavirus vaccine in a population

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