Between 1 January and 7 August 2023, a total of 69 483 dengue cases including 327 related deaths (case fatality rate = 0.47%) were reported by the Ministry of Health and Family Welfare (MOHFW). As of 30 June 2023, a total of 7978 cases and 47 deaths were reported, however, the cases started surging rapidly from late June and in the month of July alone 63% of cases (n=43 854) and 62% of deaths (n= 204) were reported. 

The number of cases and deaths are higher compared to similar periods in the past five years (Figure 1). Dengue cases started to rise in May 2023 and have been continuing since then, and the peak is unlikely to have been reached. The reported number of dengue cases this year is the highest compared to the same periods recorded since 2000.

The cases are reported from all 64 districts in the country.  Cases in Dhaka division started to increase in epidemic week 17 (23-29 April 2023) and in all eight divisions since epidemic week 26 (25 June to 1 July 2023).  The most affected area in the Dhaka division is Dhaka city corporation, accounting for 52.8% of cases and 78.9% of deaths. Other affected divisions include Chattogram division (13.2% of cases and 9.2% of deaths), Dhaka division excluding Dhaka city (11.6% of cases and 2.8% of deaths), and Barisal division (10.5% of cases and 4.3% of deaths). The Sylhet division has the lowest number of cases (560) and no deaths reported so far.

As of 7 August 2023, the reported CFR is 0.47%, which is higher compared to previous years (table 1). On further analysis, the overall CFR is higher in females than in males (0.72% v 0.32%) with females having four times higher CFR than males among those aged 21-40 years (0.71% vs 0.18%). The older age group recorded a higher CFR compared to the younger age group (1.87% in the age group over 60 years compared to 0.74% in the age group between 41 to 60 years and 0.34% in those aged 40 years and below).

DENV2 was the predominant circulating serotype in Bangladesh until 2018, when it was replaced by DENV3 as the predominant serotype since 2019.  However, DENV2 has been identified as the primary circulating serotype in this outbreak, and this may result in more severe dengue infections and hospitalizations as a result of a second infection with a heterologous serotype. Of the 66 serotyped samples in the month of June 2023, DENV2 (51.5%) and DENV3 (43.9%) were identified as the circulating serotypes.