Bangladesh experienced the second wave with Beta variant, currently battling the third wave with Delta, says Dr Firdausi Qadri
Evidence-based national policies are essential to curb Covid-19 infections in Bangladesh, scientists suggest.
Recently, a genomic epidemiology consortium comprised of the Institute of Epidemiology, Disease Control and Research (IEDCR), Bangladesh; icddr,b (formerly International Centre for Diarrhoeal Disease Research, Bangladesh), and Institute for Developing Science and Health Initiatives (ideSHi) in collaboration with local and international institutions has published a scientific paper in Nature Microbiology titled “Genomics, social media, and mobile phone data enable mapping of SARS-CoV-2 lineages to inform health policy in Bangladesh.”
The article's authors have analysed genome sequencing data of 391 SARS-CoV-2 samples collected in Bangladesh between March-July 2020 and conducted a phylogenetic analysis of the evolutionary relationship between SARS-CoV-2 lineages that emerged at different times and locations in Bangladesh during the first wave in Bangladesh.
Dr Firdausi Qadri, a senior scientist at icddr,b and a senior author of the article, commented about the emergence of new variants and associated risk.
She said as more mutations accumulate in the SARS-CoV-2’s genetic code, there would be more variants of which some could have the strength to breakthrough natural or vaccine-induced immunity.
This is already becoming evident and Bangladesh has experienced the second wave with the Beta variant and is currently battling the third wave with the Delta variant, she mentioned.
"Real-time genomic surveillance is critical to understand the efficacy of these vaccines and protection from previous Covid-19 infections and to devise relevant strategies for Bangladesh and beyond," Dr Qadri said.
Additionally, anonymised population mobility data collected from Facebook and three mobile operators were integrated with the genomic data to investigate the spatial spread of the virus in Bangladesh.
Of the 391 samples analysed from the first wave, complete genomes of 67 samples were sequenced by the consortium between March – July 2020, and the rest were collected from GISAID, which other institutions sequenced.
The analysis revealed that of the 391 sequences, 85% of isolates fell into three dominant lineages, namely lineages B.1.1, B.1.1.25, and B.1.36. Lineage B.1.1 accounted for 19% of sequences, while B.1.1.25 accounted for 58% of sequences.
Lineage B.1.36 accounted for 8% of the sequences and was predominant in southern Bangladesh with 64% of isolates found in the Chittagong Division.
To investigate the factors that led to the country-wide spread of these three dominant lineages seen at that time, the consortium examined the history of events that unfolded before the first wave of Covid-19.
Bangladesh reported the first Covid-19 case on March 8, 2020.
To contain the spread of the virus, the government announced a national public holiday with stay-at-home order on March 23, 2020, which was effective from March 26 to April 4 and later incrementally extended until May 30, 2020.
However, the population mobility data collected from Facebook and three mobile phone operators showed an important link between population movement and the spread of SARS-CoV-2.
It indicated a mass migration out of Dhaka to all areas of the country on March 23-26, 2020.