Outbreak, Surveillance, Investigation & Response (OSIR) Journal

The Grammar of Science: Do Clusters Really Matter?

2025-10-01T10:36:42+07:00

Turning the Tide on Measles: EOC-Led Response and School-Based Vaccination in Narathiwat Province’s Outbreak, 2024–2025

2025-10-01T10:36:51+07:00

This study aimed to describe the epidemiological characteristics of the 2024–2025 measles outbreak in Narathiwat Province, identify factors associated with severe illness, and evaluate the effectiveness of outbreak control measures. A suspected case was defined as fever with maculopapular rash plus cough, coryza, conjunctivitis, or Koplik’s spots. Confirmed cases had laboratory evidence of infection, detected either by measles-specific immunoglobulin M antibodies using enzyme-linked immunosorbent assay or viral RNA via reverse transcription polymerase chain reaction. Epidemiologically linked cases met clinical criteria without laboratory confirmation but had documented exposure to a confirmed case. Between February 2024 and January 2025, 2,710 cases were reported: 47.0% suspected, 13.4% epidemiologically linked, and 39.6% confirmed. Most cases occurred in children aged 9 months to 4 years, and 9.3% of confirmed cases were severe. Risk factors included female gender (adjusted odds ratio (OR) 1.81, 95% confidence interval (CI) 1.18–2.79), age under 9 months (adjusted OR 7.84, 95% CI 1.77–34.70), and diarrhea (AOR 2.29, 95% CI 1.47–3.60). Following Emergency Operations Center activation, school-based surveillance, ring vaccination, vitamin A supplementation, and a phased vaccination campaign were implemented. School-based clusters declined from 19 to 1 within 42 days post-intervention. Ring vaccination coverage reached 65% and reduced secondary infections from 2.0% to 1.3% (p-value <0.01). The vitamin A uptake rate rose rapidly, reaching 100% by October 2024. The measles vaccine coverage increased from 47.9% to 65.0% among children aged under 12 years. These results highlight the outbreak burden in low-coverage areas and support integrated interventions.

Drunk Driving, Sleep Deprivation, Unsafe Vehicle, and Poor Road Design: Converging Hazards in a Road Traffic Crash in Sukhothai Province, Thailand, 2025

2025-10-01T10:36:47+07:00

Road traffic injuries are a leading cause of death globally, with alcohol impairment increasing the risk of an accident.
At 7:10 AM on 10 Feb 2025, a pickup truck rear-ended a passenger vehicle carrying students in Sukhothai, Thailand. This study aimed to identify factors associated with the crash and recommend preventive measures. Data were collected through medical record reviews, site surveys, interviews with witnesses and stakeholders, and a joint agency meeting. Haddon’s Matrix guided the analysis. All 20 occupants (2 drivers, 18 students) sustained injuries, with one case requiring admission for eyelid laceration. The weather was clear, the road was dry, and both drivers were experienced. Pre-crash risks included driver intoxication (blood alcohol concentration of 133 mg/dL) and drowsiness, the use of a modified passenger vehicle with unsafe seating and no seatbelts, and an inadequate road design, specifically a sudden lane reduction and a sub-standard U-turn constructed at villagers’ request. Crash-phase risks included speeding, an abrupt lane change, and a steep roadside with a narrow (30 cm) shoulder, which caused the passenger vehicle to overturn. Post-crash issues included a lack of initial scene management, resulting in poor crowd control. This incident illustrates how alcohol impairment, an unsafe passenger vehicle, poor road design, and emergency response gaps contributed to the crash severity. The investigation led to policy actions, including U-turn closures, school transport vehicle reforms, and improved emergency medical services training. The value of field investigations in turning real-world crashes into targeted, system-level prevention strategies is underscored.

Performance of the Severe Acute Respiratory Infection (SARI) Surveillance System: A Case Study of Chey Chumneas Hospital, Kandal Province, Cambodia, 2022

2025-10-01T10:37:01+07:00

Cambodia’s Severe Acute Respiratory Infection (SARI) surveillance system was established in 2012. The system monitors SARI cases, detects outbreaks, and identifies influenza trends. However, the system has not undergone evaluation since its inception. This evaluation aimed to assess surveillance attributes at Chey Chumneas Hospital, Kandal Province. A mixed-methods approach was utilized, following US-CDC guidelines. Medical records in 2022 were reviewed to assess sensitivity and positive predictive value (PPV). Case reporting forms were reviewed to determine completeness. The timeliness of weekly reports in the system and the release of laboratory results were evaluated. Semi-structured interviews with key stakeholders were used to assess qualitative attributes. Between 2018 and 2022, 576 SARI cases were reported. The sensitivity in detecting true SARI cases among admitted patients was 33%, and the PPV was 73%. In 2022, 54% (28/52 weeks) of weekly reports were submitted on time, and 59% (52/88) of SARI cases had laboratory results released within 24 hours. Of 88 case reporting forms, 91% of socio-demographic and date of onset variables were complete, and three SARI symptom variables had a completion of 95%. The system was positive in terms of usefulness, simplicity, acceptability, and flexibility, but stability was relatively weak due to dependence on external funding. The system was useful in estimating morbidity and mortality and monitoring influenza trends. Although its performance was good, gaps in sensitivity, timeliness, and stability remained. Targeted training, supervision for the hospital SARI focal point, and sustained financial support are needed to improve the surveillance system’s performance.

High Sensitivity with Suboptimal Predictive Value and Delayed Reporting: Identifying Gaps in Congenital Zika Syndrome Surveillance at Saraburi Hospital, Thailand, 2022–2023

2025-10-01T10:36:49+07:00

Zika virus is an arboviral infection primarily transmitted by Aedes mosquitoes, with severe complications in children, notably congenital Zika syndrome (CZS). This study evaluates the surveillance system of CZS based on the R506 reporting system, the nationwide reporting platform of the Department of Disease Control, at Saraburi Hospital, Thailand, during 2022–2023. We employed both quantitative and qualitative methods. A cross-sectional quantitative study was conducted through a review of hospital records and R506 surveillance data. Attributes such as sensitivity and positive predictive value (PPV) were calculated. For the qualitative study, attributes such as acceptability, simplicity, flexibility, and stability were assessed mainly through semi-structured interviews, and a framework analysis was conducted. The surveillance system demonstrated a sensitivity of 100.0% and a PPV of 44.4%. Completeness was high for demographic variables; however, timeliness was suboptimal, with 11.1% of reports submitted within a one-week window. The system was deemed useful and stable; however, challenges in interoperability between R506 and the hospital database were noted. Notably, the in-house hospital laboratory lacked the capacity to perform Zika polymerase chain reaction (PCR) tests, necessitating external processing and likely contributing to reporting delays. While the surveillance system could detect cases effectively, improvements in timeliness, coding consistency, and data integration are needed. Revising the case definition could increase the PPV. Enhancing the hospital's laboratory capacity, particularly for PCR testing, may reduce reporting time. Strengthening reporting practices and stakeholder collaboration could further improve system efficiency.

Modeling the Potential Spread of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and Evaluating Strategic Preparedness Measures in Thailand

2025-10-01T10:36:44+07:00

Middle East respiratory syndrome (MERS) remains a public health threat due to its severity and potential for nosocomial and international transmission. Thailand remains at risk of a MERS outbreak due to ongoing travel, pilgrimage, and trade with the Middle East, despite having no confirmed case since 2016. This study aimed to assess the potential spread of MERS-CoV and evaluate national preparedness for MERS outbreaks by using a mixed-methods study. A quantitative study employed Susceptible-Exposed-Infectious-Recovered models to simulate the dynamics of MERS outbreaks under various scenarios in Yala, Pattani, and Narathiwat provinces. The qualitative component included documentary reviews and in-depth interviews with 21 key policymakers, experts, and relevant officers from provincial, sub-national, national, and international levels. The modeling revealed a low likelihood of widespread outbreaks, and combined interventions and early detection resulted in decreased peak and cumulative outcomes across various basic reproductive number values. Documentary reviews revealed that in Thailand, MERS surveillance was integrated into the national communicable disease surveillance, and its priority has diminished since 2016. In-depth interviews showed strengths in strategic plans, human resources, and cross-sector coordination, although gaps were identified in MERS-specific surveillance systems, laboratory surge capacity, insufficient community-level preparedness, and fragmented data systems. The results showed that Thailand has foundational capacity for MERS, supported by enhanced public health infrastructure following the COVID-19 pandemic. Recommendations include strengthening combined intervention and early detection measures, MERS-specific surveillance protocols, laboratory capacities, health literacy among high-risk groups such as pilgrims and caregivers, preparing sufficient resources, and enhancing digital health systems.