Figure 1

Figure 1. Surveillance, reporting, and laboratory specimen pathways during large measles outbreak, Bangladesh, 2026. AHI, assistant health inspector; DGHS, Directorate General of Health Services; DHIS2, district health information software 2; EPI, Expanded...

In response to the outbreak, the Ministry of Health and Family Welfare followed its established data flow, reporting, and laboratory interoperability plan for measles surveillance (Figure 1). The surveillance system covers facility- to national-level operations for case detection and notification, data and sample collection, reporting, and laboratory testing.

Epidemic Trajectory

Figure 2

Figure 2. Daily epidemic curve showing the distribution of suspected and confirmed cases during large measles outbreak, Bangladesh, 2026. A) Overall confirmed and suspected cases during April 2–May 27, 2026, overlaid with...

Figure 3

Figure 3. Geographic distribution during large measles outbreak, Bangladesh, 2026. Map shows cases/100,000 population for each division during March 15–May 27, 2026; the outbreak is ongoing. Data were sourced from Bangladesh Directorate...

The daily epidemic curve from April 2–May 27, 2026, showed a peak of 1,829 cases reported in a single day on April 9, 2026 (Figure 2) (9). Reported cases reflected early explosive spread before initiation of the nationwide vaccination response on April 5, 2026. Using case counts from the DGHS and 2022 Bangladesh census population data (10), we calculated incidence rates for each division. Dhaka division reported the highest incidence (82.80 cases/100,000 population), followed by Barishal (65.63/100,000) and Rajshahi divisions (35.22/100,000); Rangpur reported the lowest incidence (7.63/100,000) (Figure 3).

Bangladesh is experiencing its largest measles outbreak on record, and a total of 75,913 cases and 560 deaths were recorded in 56 days (8). The ongoing outbreak shows no sign of slowing, and the highest cumulative weekly death toll came during May 21–27, 2026, the last week recorded before this report. This soaring disease burden signifies several observations.

First, the highest weekly case count (10,427 cases with 62 deaths) was recorded May 7–13 (https://doi.org/10.17605/OSF.IO/RHQUS), when vaccination coverage exceeded 100% of the administrative target (Figure 2). That pattern demonstrates a large preexisting susceptible population. The impact of emergency mass vaccination typically becomes evident within 2–4 weeks as vaccinated children acquire protection and the susceptible pool diminishes. The practical lesson is that herd protection thresholds must be maintained continuously through routine and catch-up vaccination, not reactive campaigns.

Second, the large gap between suspected and laboratory-confirmed cases (≈7:1) partly reflected the usual surveillance practice, since not every suspected case required laboratory confirmation. However, that gap might also reflect limited testing capacity because only 1 laboratory facility serves the country. Moreover, a case-level linkage between tested specimens and surveillance records was not available, so the positive predictive value could not be calculated. The reported CFR in Bangladesh during this outbreak was 0.88% for suspected cases and 0.99% for confirmed cases, which should be interpreted cautiously given that limitation. Those rates were higher than rates reported in the United States and Europe (0.13% each) but within the 1.5%–5.35% range reported in some low- and lower middle–income settings (14–16). However, the observed CFR of Bangladesh reflected cases reaching healthcare facilities rather than the true population-level rate. Consequently, limited community-based reporting of mild illness likely biased the CFR upward.

Third, the high (70%) hospitalization rate among reported cases should be discussed cautiously; measles cases reported through the surveillance systems typically represent a fraction of the true number of cases because many children are not assessed by clinicians (17). In addition, when medical care is sought, measles might be misdiagnosed or cases might not be reported to authorities (17).

Fourth, measles cases were reported across all 8 divisions from the beginning of the outbreak, indicating widespread transmission amid nationwide immunity gaps. Contributing factors include the 2024–2025 MR vaccine stockout, gaps in routine immunization, and the absence of nationwide MR campaigns since 2020 (6), a pattern also seen in other low- and middle-income countries after immunization disruptions (18,19). Part of that gap might be further underestimated by reporting discrepancies: Bangladesh’s administrative coverage, the reported number of vaccine doses administered divided by the estimated target population, still calculated on the basis of 2011 census denominators, has exceeded 100% in places, pointing to denominator underestimation and overreporting that likely mask the true extent of population immunity gaps (20).

In line with WHO guidance (21), we recommended several measures to control the outbreak. Those measures included continuing the MR campaign in periurban and other low-coverage areas to reach underimmunized populations; strengthening community engagement and caregiver education to increase vaccine demand and address misinformation; ensuring routine Expanded Programme on Immunization service delivery with adequate supply, with special attention to low-coverage districts; and strengthening real-time sentinel measles surveillance to detect future outbreaks early.