Five of the patients had received two doses of the University of Oxford/AstraZeneca vaccine.
Chattogram General Hospital and Chattogram University’s genetic engineering and biotechnology department conducted the study on 24 patients at the hospital under the supervision of Child Health Research Foundation.
The findings have been included in the Global Initiative on Sharing All Influenza Data.
Dr Abdur Rab of the state-run hospital in the port city said 10 of the 24 patients were admitted to the Intensive Care Unit for severe illness while the rest were at the isolation ward or outpatients with mild to moderate symptoms.
Genome sequencing showed eight of the ICU patients and 75 percent of the rest had the Beta variant, first identified in South Africa. Most of them had fever, cough and cold.
The others had the Alpha variant, first detected in Britain, with mild symptoms.
All the patients who required medical oxygen extensively through high flow nasal cannula had the Beta variant.
The researchers did not find the Delta variant of the virus during the study until the third week of May.
The variant, which caused widespread deaths during a second wave of infections in India, has recently been found in Bangladesh’s border districts that have emerged as new COVID hotspots.