Clinical Scorecard: Surveillance of Influenza A, RSV B, and SARS-CoV-2: An Epidemiological and Genomic Study in Bangladesh (2022-2024)

At a Glance

Key highlights

• The National Respiratory Pathogen Genomic Surveillance consortium was established in Bangladesh in 2022.

• Oxford Nanopore sequencing was supplemented by Illumina sequencing for benchmarking and cross-platform validation.

• Influenza A was prioritized because it accounted for more than 95% of influenza cases; RSV B was prioritized because it was the predominant circulating RSV subtype.

• A randomized monthly specimen-selection strategy was implemented to reduce sampling bias.

• Genomic sequences were contributed to the Global Initiative on Sharing All Influenza Data database.

Study implications

Surveillance eligibility

• Patients met World Health Organization clinical criteria for SARI or ILI.

Public health planning

• Surveillance findings may support public health planning, including future evaluation of RSV prevention strategies.

Monitoring

• Continued genomic surveillance can track the circulation, seasonality, and evolution of SARS-CoV-2, influenza viruses, and RSV.

Key findings

• RSV caused a substantial burden among children younger than 5 years, particularly infants.

• Influenza peaked during the 2023 monsoon, whereas SARS-CoV-2 maintained low-level circulation.

Study population and testing

• Respiratory specimens were collected from patients meeting criteria for SARI or ILI.

• RSV testing was conducted exclusively among children younger than 5 years.

• Sequencing was limited to positive specimens with cycle-threshold values of 27 or lower.

Surveillance considerations

• Integrated multipathogen genomic surveillance was feasible in this resource-limited setting.

• Predominantly urban sentinel sites may underrepresent rural transmission.

• Selecting high-viral-load specimens for sequencing may introduce selection bias.

Related resources and content

• Original study: Epidemiological and genomic surveillance of influenza virus A, RSV B, and SARS-CoV-2 in Bangladesh, 2022-2024

• WHO global epidemiological surveillance standards for influenza

• WHO Global Influenza Surveillance and Response System

• GISAID genomic sequence database

• Study data-analysis code on GitHub

• Related study: RSV-associated hospitalizations in Bangladeshi children younger than 5 years