Epidemiological, clinical, and diagnostic characteristics of a large-scale upsurge of dengue in the rohingya refugee camps and host communities in Cox’s Bazar, Bangladesh, 2021 to 2024: A retrospective study
6 affiliations
- 1Migration Health Division (MHD), International Organization for Migration (IOM), Cox’s Bazar, Bangladesh
- 2Migration Health Research Unit, Regional Office for Asia and the Pacific, International Organization for Migration (IOM), Bangkok, Thailand
- 3World Health Organization, Cox’s Bazar, Bangladesh
- 4Civil Surgeon Office, Cox’s Bazar, Bangladesh
- 5Refugee Relief & Repatriation Commissioner Office, Cox’s Bazar, Bangladesh
- 6Cox’s Bazar Medical College, Cox’s Bazar, Bangladesh
Abstract
Background: Dengue emerged as a new public health threat in the Rohingya refugee camps in Cox’s Bazar, Bangladesh, in 2021 and expanded into large-scale upsurges in subsequent years. Evidence on dengue epidemiology and clinical presentation in protracted refugee settings remains limited, despite the need for stronger outbreak preparedness and case management in these contexts. Objectives: To describe the epidemiological, clinical, and diagnostic characteristics of the dengue upsurge among Rohingya refugees and surrounding host communities in Cox’s Bazar, Bangladesh, and to identify predictors of inpatient admission and diagnostic positivity patterns. Methods: This retrospective observational study used anonymized surveillance data from the International Organization for Migration (IOM) dengue patient database. Rapid diagnostic test (RDT)–confirmed dengue cases identified across 36 IOM-supported health facilities in Ukhiya and Teknaf between 1 October 2021 and 31 December 2024 were included. Demographic, epidemiological, clinical, and laboratory variables were summarized using descriptive statistics. Weekly case counts were aggregated by epidemiological week and calendar year, and epidemic growth and decay phases were modelled using phase-specific Poisson regression. Multivariable logistic regression was used to identify factors associated with inpatient admission, while separate models examined associations between delay in presentation and RDT positivity patterns, adjusting for age and sex. Results: A total of 35,581 RDT-confirmed dengue cases were reported, of which 90.2% occurred among Rohingya refugees. The median age was 17 years (IQR 7–30), and 46.0% of cases were among children aged 0–14 years. Annual caseload increased from 1,011 in 2021–11,752 in 2022, 10,669 in 2023 and 12,149 in 2024, with seasonal peaks during the monsoon period and progressively later peaks and longer epidemic tails over time. Poisson models showed decreasing growth rates across years (r = 0.449 in 2021 to r = 0.091 in 2024) with increasing doubling times, while decay rates remained broadly comparable (halving time ~4.4–6.0 weeks). Overall, 8.0% of cases required inpatient admission, 1.3% were referred, and four deaths were reported (case fatality <0.1%). In multivariable analysis, inpatient admission was associated with older age (≥60 vs 0–14: aOR 2.48), delayed presentation (aOR 1.06 per day), refugee status (aOR 1.43), fever ≥38°C at presentation (aOR 1.13), presence of any WHO warning sign (aOR 28.87), and chronic co-morbidity (aOR 6.63). Males had lower odds of admission than females (aOR 0.87). Conclusion: Sustained dengue preparedness is required in Cox’s Bazar, including strengthened surveillance, community-based early referral, targeted monitoring of high-risk groups, environmental vector control, and phase-appropriate use of NS1 and IgM/IgG diagnostics to reduce missed diagnoses and prevent progression to severe disease. These findings highlight the need for a policy shift from episodic outbreak response toward sustained dengue preparedness in humanitarian settings, including strengthened surveillance systems, integrated diagnostic strategies, community-based early referral, and coordinated vector control interventions. Author summary: Dengue has emerged as an important public health threat in the Rohingya refugee camps and surrounding host communities in Cox’s Bazar, Bangladesh. However, evidence describing dengue epidemiology and clinical presentation in refugee settings remains limited. We analyzed routinely collected surveillance data from 35,581 rapid diagnostic test-confirmed dengue cases attending 36 IOM-supported health facilities between October 2021 and December 2024. Dengue cases increased substantially after the initial outbreak in 2021, with seasonal peaks occurring during and after the monsoon period. Children represented a large proportion of reported cases, while older age, delayed presentation, chronic co-morbidities, and clinical warning signs were associated with inpatient admission. Diagnostic positivity also varied according to the timing of presentation, reflecting the expected transition from early NS1 antigen detection to later antibody detection. These findings demonstrate the growing operational burden of dengue in this prolonged humanitarian setting. Strengthening surveillance, early referral, diagnostic capacity, vector control, and preparedness may help humanitarian health systems identify cases earlier and respond more effectively to future dengue outbreaks.
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BibTeX
@article{halder2026epidemiological,
title = {{Epidemiological, clinical, and diagnostic characteristics of a large-scale upsurge of dengue in the rohingya refugee camps and host communities in Cox’s Bazar, Bangladesh, 2021 to 2024: A retrospective study}},
author = {Charls Erik Halder and Md Abeed Hasan and Emmanuel Roba Soma and James Charles Okello and Md Mostafizur Rahman and Partha Pratim Das and U. Maung Prue and Dickson Wafula Barasa and Md Atiquzzaman and Md Sobuz Hosen and Saddam Hossain Shagar and Elizabeth Yie Chuen Chong and Debashish Paul and S. M. Niaz Mowla and Mohammadul Hoque and Abu Toha MHR Bhuiyan and Md Farhad Hussain},
journal = {PLOS Neglected Tropical Diseases},
year = {2026},
month = oct,
doi = {10.1371/journal.pntd.0014198},
url = {https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014198},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Epidemiological, clinical, and diagnostic characteristics of a large-scale upsurge of dengue in the rohingya refugee camps and host communities in Cox’s Bazar, Bangladesh, 2021 to 2024: A retrospective study
AU - Charls Erik Halder
AU - Md Abeed Hasan
AU - Emmanuel Roba Soma
AU - James Charles Okello
AU - Md Mostafizur Rahman
AU - Partha Pratim Das
AU - U. Maung Prue
AU - Dickson Wafula Barasa
AU - Md Atiquzzaman
AU - Md Sobuz Hosen
AU - Saddam Hossain Shagar
AU - Elizabeth Yie Chuen Chong
AU - Debashish Paul
AU - S. M. Niaz Mowla
AU - Mohammadul Hoque
AU - Abu Toha MHR Bhuiyan
AU - Md Farhad Hussain
PY - 2026
DA - 2026/10/23
JO - PLOS Neglected Tropical Diseases
DO - 10.1371/journal.pntd.0014198
UR - https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014198
AB - Background: Dengue emerged as a new public health threat in the Rohingya refugee camps in Cox’s Bazar, Bangladesh, in 2021 and expanded into large-scale upsurges in subsequent years. Evidence on dengue epidemiology and clinical presentation in protracted refugee settings remains limited, despite the need for stronger outbreak preparedness and case management in these contexts. Objectives: To describe the epidemiological, clinical, and diagnostic characteristics of the dengue upsurge among Rohingya refugees and surrounding host communities in Cox’s Bazar, Bangladesh, and to identify predictors of inpatient admission and diagnostic positivity patterns. Methods: This retrospective observational study used anonymized surveillance data from the International Organization for Migration (IOM) dengue patient database. Rapid diagnostic test (RDT)–confirmed dengue cases identified across 36 IOM-supported health facilities in Ukhiya and Teknaf between 1 October 2021 and 31 December 2024 were included. Demographic, epidemiological, clinical, and laboratory variables were summarized using descriptive statistics. Weekly case counts were aggregated by epidemiological week and calendar year, and epidemic growth and decay phases were modelled using phase-specific Poisson regression. Multivariable logistic regression was used to identify factors associated with inpatient admission, while separate models examined associations between delay in presentation and RDT positivity patterns, adjusting for age and sex. Results: A total of 35,581 RDT-confirmed dengue cases were reported, of which 90.2% occurred among Rohingya refugees. The median age was 17 years (IQR 7–30), and 46.0% of cases were among children aged 0–14 years. Annual caseload increased from 1,011 in 2021–11,752 in 2022, 10,669 in 2023 and 12,149 in 2024, with seasonal peaks during the monsoon period and progressively later peaks and longer epidemic tails over time. Poisson models showed decreasing growth rates across years (r = 0.449 in 2021 to r = 0.091 in 2024) with increasing doubling times, while decay rates remained broadly comparable (halving time ~4.4–6.0 weeks). Overall, 8.0% of cases required inpatient admission, 1.3% were referred, and four deaths were reported (case fatality <0.1%). In multivariable analysis, inpatient admission was associated with older age (≥60 vs 0–14: aOR 2.48), delayed presentation (aOR 1.06 per day), refugee status (aOR 1.43), fever ≥38°C at presentation (aOR 1.13), presence of any WHO warning sign (aOR 28.87), and chronic co-morbidity (aOR 6.63). Males had lower odds of admission than females (aOR 0.87). Conclusion: Sustained dengue preparedness is required in Cox’s Bazar, including strengthened surveillance, community-based early referral, targeted monitoring of high-risk groups, environmental vector control, and phase-appropriate use of NS1 and IgM/IgG diagnostics to reduce missed diagnoses and prevent progression to severe disease. These findings highlight the need for a policy shift from episodic outbreak response toward sustained dengue preparedness in humanitarian settings, including strengthened surveillance systems, integrated diagnostic strategies, community-based early referral, and coordinated vector control interventions. Author summary: Dengue has emerged as an important public health threat in the Rohingya refugee camps and surrounding host communities in Cox’s Bazar, Bangladesh. However, evidence describing dengue epidemiology and clinical presentation in refugee settings remains limited. We analyzed routinely collected surveillance data from 35,581 rapid diagnostic test-confirmed dengue cases attending 36 IOM-supported health facilities between October 2021 and December 2024. Dengue cases increased substantially after the initial outbreak in 2021, with seasonal peaks occurring during and after the monsoon period. Children represented a large proportion of reported cases, while older age, delayed presentation, chronic co-morbidities, and clinical warning signs were associated with inpatient admission. Diagnostic positivity also varied according to the timing of presentation, reflecting the expected transition from early NS1 antigen detection to later antibody detection. These findings demonstrate the growing operational burden of dengue in this prolonged humanitarian setting. Strengthening surveillance, early referral, diagnostic capacity, vector control, and preparedness may help humanitarian health systems identify cases earlier and respond more effectively to future dengue outbreaks.
SN - 1935-2735
SN - 1935-2727
ER -