Influenza B in a temperate region of northern India 2010–2016: co-circulation of the two lineages with northern hemispherical seasonality

• Published in: Virusdisease Vol. 29; no. 4; pp. 553 - 559
• Main Authors: Koul, Parvaiz A., Potdar, Varsha, Showkat, Masooma, Mir, Hyder, Chadha, M. S.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.12.2018; Springer Nature B.V
• Subjects: Age groups; Biochemistry; Biomedical and Life Sciences; Cell Biology; Cough; Epidemiology; Fever; Influenza; Influenza A; Influenza B; Life Sciences; Microbiology; Pandemics; Patients; Phylogeny; Protein Structure; Respiratory diseases; Respiratory tract infection; Seasonal variations; Short Communication; Software; Surveillance; Vaccine efficacy; Vaccines; Viruses; India; Influenza B virus; Trivalent influenza vaccine; B/Yamagata; B/Victoria; Quadrivalent influenza vaccine; Influenza
• ISSN: 2347-3584; 2347-3517
• DOI: 10.1007/s13337-018-0487-8

Scant data exist about the epidemiology of influenza B in India. We set out to address the epidemiology of influenza B in a temperate region of northern India from 2010 to 2016. Outpatient and inpatient surveillance was conducted in patients presenting with acute respiratory infection in a northern Indian hospital from September 2010 till April 2016. After recording clinical data, combined nasal/throat swabs were collected and tested for influenza viruses by real time RT-PCR. Influenza A viruses were further subtyped into A/H3N2 and A/H1N1 whereas influenza B were differentiated into B/Yamagata and B/Victoria. Virus isolation, haemaggglutination inhibition testing, sequencing and phylogenetic analysis was carried out on representative samples. Of the 6879 recruited cases, influenza B was detected in 299 (4.3%). The patients presented with respiratory symptoms of varying duration; cough, fever and nasal discharge being the most common. The peaking of the activity of the circulation showed a correlation with the onset of the winter with reduced temperatures and high dry humidity. B/Victoria lineage was detected in 35.4% (n = 106/299) whereas 53.8% (n = 161/299) were B/Yamagata. The circulation in each season was dominated by one lineage which correlated with the vaccine strain, but up to 37% consisted of a different lineage. We conclude that Influenza B exhibits a northern hemispherical seasonality in temperate northern India with co-circulation of the 2 lineages of influenza B. These findings have relevance for vaccine effectiveness and argue for vaccination with a quadrivalent influenza vaccine.