Supplementary material from: Burden of Shigella among children with diarrhea in the Americas: A systematic review and meta-analysis

Introduction: Shigella infection is a leading cause of diarrhea
worldwide. While the burden of Shigella has been shown
to be highest in Africa and Asia, recent studies have also shown
considerable burden in the Americas. With several
pediatric Shigella vaccines in clinical development,
policymakers in the region will eventually consider whether
a Shigella vaccine is appropriate for their
setting.  Methods: We conducted a systematic review and
meta-analyses to summarize the burden (characterized by prevalence,
incidence, and attributable fraction estimates)
of Shigella diarrhea among children under 72 months in
the Americas, excluding the U.S., Canada, and Greenland. We searched
published and pre-print articles available in six databases from January
1, 2000 through July 23, 2024. Random effects meta-analyses were conducted
for subgroups of interest when relevant data from at least two studies
were present. Results: This review included 34 studies conducted across 14
countries in the region. Prevalence was most frequently reported, followed
by incidence, then attributable fraction. Across all prevalence studies
that used a culture detection method (n=23), the pooled prevalence
of Shigella among diarrhea cases was 3.1% (95% CI: 1.6-
5.8). The pooled prevalence among 12 studies that used PCR/qPCR detection
methods was 16.5% (95% CI: 11.1-24.0). Among culture-based results, the
pooled prevalence estimate for children <12 months was 1.0% (95%
CI: 0.1 – 7.7) compared to 4.6% (95% CI: 1.2 – 15.4) for children ≥12
months. Conclusion: Despite varying reporting practices, we
found Shigella to be an important contributor to
diarrhea in many settings in the Americas with substantial heterogeneity.
Limited geographic representation and variable reporting of age group
specific estimates were the major gaps in data. Investment
in Shigella surveillance in the Americas using a
standardized methodology can contribute to accelerating Shigella
vaccine development in consideration of regional preferences and optimal
age of introduction.