Epidemiology and Health

Original Articles

Childhood mortality from acute diarrheal disease in Paraguay and vaccination impact: a 31-year ecological study: María Eugenia Galeano, Magaly Martínez, Anibal Francisco Espínola, Eliana Andrea Alvarenga, Margarita Samudio; Epidemiol Health. 2026;48:e2026010. Published online February 20, 2026; DOI: https://doi.org/10.4178/epih.e2026010

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
Acute diarrheal disease (ADD) remains a leading cause of morbidity and mortality in children under 5 worldwide. In Paraguay, the introduction of the rotavirus vaccine in 2010 aimed to reduce the burden of ADD in infants and young children. This study analyzed 31 years of public data on ADD morbidity and mortality in Paraguayan children under 5 and evaluated the impact of rotavirus vaccination.
METHODS
Annual ADD incidence, total deaths, and mortality rates from 1993 to 2023 were obtained from public databases. Proportionate mortality due to ADD, cause-specific mortality rates, absolute risk reduction (ARR) and relative risk reduction (RRR), and joinpoint regression were calculated using EPIDAT 4.2 and Joinpoint 5.3.0 software, with data stratified by age group and vaccination period.
RESULTS
Between 1993 and 2021, pediatric mortality in Paraguay declined steadily across all age groups. Following the introduction of Rotarix in 2010, infant mortality dropped from 2.36 to 0.19 deaths per 1,000 live births (ARR, 0.83; RRR, 81.4%). Joinpoint analysis showed a decline in under-5 mortality between 2009 and 2012 (annual percentage change=−35.2%, p<0.05), followed by stabilization. ADD incidence increased until 2019 and then declined, while vaccine coverage exceeded 70%.
CONCLUSIONS
Paraguay has sustained declines in infant and childhood mortality over 3 decades through improvements in healthcare and immunization, with the 2010 introduction of Rotarix reducing the mortality rate by 43 deaths per 100,000 infants under 12 months. These results underscore the impact of vaccination and health system strengthening, while highlighting the need to monitor emerging threats.; Summary

Key Message
Despite the introduction of rotavirus vaccination in Paraguay, long-term trends in acute diarrheal disease remained understudied. This 31-year analysis reveals a substantial decline in ADD-specific mortality following vaccine implementation, especially in children aged 1-4. However, ADD incidence resurged after 2013, highlighting gaps in disease control beyond vaccination. These findings underscore the vaccine’s impact while exposing the need for integrated surveillance and broader public health strategies to sustain progress and address residual disease burden.

Bacillus of Calmette and Guérin (BCG) and the risk of leprosy in Ciudad del Este, Paraguay, 2016-2017: Nancy Carolina Cuevas, Victor M. Cardenas; Epidemiol Health. 2021;43:e2021060. Published online September 8, 2021; DOI: https://doi.org/10.4178/epih.e2021060

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4 Crossref

Abstract

OBJECTIVES
Paraguay has experienced a 35% reduction in the detected incidence of leprosy during the last ten years, as the vaccination coverage against tuberculosis (Bacillus of Calmette and Guérin [BCG] vaccine) reached ≥95% among infants. The objective of this case-control study was to evaluate the protective effect of BCG on the risk of leprosy.

METHODS

We used a population-based case-control study of 20 leprosy confirmed cases reported among residents of Ciudad del Este, Paraguay, diagnosed in 2016-2017. Three controls were selected from a random sample of households from the city. We assessed vaccine effectiveness using 1- odds ratio [OR], and confounding for age, gender, education, occupation, and marital status using stratified and exact logistic regression, and explored if there was effect modification calculating the synergy factor (SF) and relative excess risk due to interaction (RERI).

RESULTS

After controlling for age, gender, education, occupation and marital status, the OR of BCG scar on the risk of leprosy was 0.10 (95% confidence interval [CI], 0.02 to 0.45), for an estimate of vaccine effectiveness of 89.5% reduced risk of leprosy (95% CI, 55.2 to 98.1). There was evidence of heterogeneity by which the effectiveness of BCG seemed stronger among younger persons (Breslow-Day and Z-test of the SF had a p<0.05), and both the RERI and SF indicated a less then multiplicative and additive interaction of BCG and younger age.

CONCLUSIONS

BCG vaccination was associated with a decreased risk of leprosy in the study population, particularly in persons born after 1980.

Summary

Key Message
Paraguay had the second highest reported incidence in the Americas, but no previous study had investigated the topic of BCG for leprosy in Paraguay. We confirmed that BCG protected from leprosy, hence it may have contributed to the observed decline of leprosy.

Citations

Citations to this article as recorded by

Autoantibodies and vitamin D in leprosy patients in the Brazilian Amazon
Glaucielen Gomes da Silva, Tinara Leila de Souza Aarão, Lucas Corrêa Modesto, Luis Arthur Moreira Ferreira, Pablo Rodrigues Nunes de Souza, Rafael Malcher Meira Rocha, Luiz Fábio Magno Falcão, Juarez Antônio Simões Quaresma
BMC Infectious Diseases.2026;[Epub] CrossRef
An update of the diagnosis, treatment, and prevention of leprosy: A narrative review
Chien-Yuan Huang, Shih-Bin Su, Kow-Tong Chen
Medicine.2024; 103(34): e39006. CrossRef
Comparison of Antiphenolic Glycolipid-1 Antibody Levels in Seropositive Contacts of Leprosy after 2 Years of Single-dose Rifampicin as Postexposure Prophylaxis
Odelia Jovita Jusuf Fantoni, Rusmawardiana, Yulia Farida Yahya, Erial Bahar, Theresia Lumban Toruan, Muhammad Izazi Hari Purwoko
The International Journal of Mycobacteriology.2023; 12(4): 399. CrossRef
BCG and SARS-CoV-2—What Have We Learned?
Jakub Kulesza, Ewelina Kulesza, Piotr Koziński, Wojciech Karpik, Marlena Broncel, Marek Fol
Vaccines.2022; 10(10): 1641. CrossRef

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