A study has found that 75 percent of Covid-19 patients who came to a hospital in Chattogram for treatment between April and May were infected with a beta variant of coronavirus originating in South Africa.
Besides, 25 percent of the patients were infected with the UK's "alpha variant".
The study, however, did not find any evidence of the presence of India's "delta variant".
The information was obtained by sequencing the genome of the virus from the samples of 24 patients infected with coronavirus in Chittagong General Hospital.
The study was carried out by researchers from the General Hospital and the Department of Genetic Engineering and Biotechnology, University of Chittagong, under the supervision of the Dhaka Child Health Research Foundation.
The study participants said that their genome sequence data was taken from the Global Initiative on Sharing All Influenza Data (GISAID), an international database of viruses published in Germany.
The study found that five of the 24 patients had taken the second dose of the vaccine.
They contracted Covid-19 two weeks after vaccination with the beta type found in all of them.
In addition, 10 out of 24 people received treatment in the Intensive Care Unit (ICU). Eight out of 10 people were affected by beta type.
The study was led by Senjuti Saha, a scientist at the Child Health Research Foundation.
The main researchers were HM Hamidullah Mehedi and Abdur Rob, doctors of the Covid unit of the General Hospital. Md Minhazul Haque and Rajdeep Biswas were the co-researchers.
The study was also supervised by Adnan Mannan, associate professor, Department of Genetic Engineering and Biotechnology, University of Chittagong.
Dr Abdur Rob said, "Among the patients, 75 percent were infected with beta variant and 25 percent with alpha variant. However, no one was infected with the delta variant which was found in India.
"All the patients who needed ICU and high flow oxygen were infected with the beta variants. Ninety percent of those infected with the alpha variant had symptoms of fever and cold," he added.
On 4 April, The Business Standard, under the headline "Fear of new covid strains grows amid lack of research", reported the presence of the South African variant in Chattogram for the first time.
At the time, Chattogram Divisional Health Director Hasan Shahriar Kabir told The Business Standard, "The new variant has a higher mortality rate among Covid-19 patients in Chattogram. The South African and Brazilian variants have spread in the port city. "
Sheikh Fazle Rabbi, Chattogram civil surgeon, said 54,807 people had been infected with coronavirus in Chattogram till Saturday. Of them, 642 people died.