Influenza B viruses co-circulate with influenza A each season and also cause significant illness, especially in children; they lead to seasonal flu outbreaks and can cause severe pneumonia and hospitalizations. Despite lower overall incidence, B strains are included because they contribute substantially to seasonal influenza burden and have distinct vaccine and treatment considerations (Owusu et al. 2019, Charlton et al. 2018).
References:
Charlton, C. L., Babady, E., Ginocchio, C. C., Hatchette, T. F., Jerris, R. C., Li, Y., Loeffelholz, M., McCarter, Y. S., Miller, M. B., Novak-Weekley, S., Schuetz, A. N., Tang, Y. W., Widen, R., & Drews, S. J. (2018). Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections. Clinical microbiology reviews, 32(1), e00042-18. https://doi.org/10.1128/CMR.00042-18
Owusu, D., Hand, J., Tenforde, M. W., Feldstein, L. R., DaSilva, J., Barnes, J., Lee, G., Tran, J., Sokol, T., Fry, A. M., Brammer, L., & Rolfes, M. A. (2020). Early Season Pediatric Influenza B/Victoria Virus Infections Associated with a Recently Emerged Virus Subclade – Louisiana, 2019. MMWR. Morbidity and mortality weekly report, 69(2), 40–43. https://doi.org/10.15585/mmwr.mm6902e1
