The recent recommendation by the World Health Organization (WHO) to exclude the influenza B/Yamagata lineage from future influenza vaccines has sparked a significant shake-up in the field of influenza vaccination. This move was highlighted in the editorial of ‘The Lancet’ edition on ‘Infectious Diseases’ of December 2023 edition. It has far-reaching implications for vaccine formulation, distribution strategies, and future influenza control efforts. In this commentary, NSH delves into the Lancet editorial’s key points, provide critical analysis, and discuss the potential impact of this influenza vaccine shake-up.
Excluding the B/Yamagata lineage
‘The Lancet’ Infectious Diseases editorial, published in December 2023, sheds light on the unprecedented decision made by the WHO to exclude the B/Yamagata lineage from influenza vaccines for the upcoming season in the Southern Hemisphere. The editorial highlights the unique circumstances surrounding this decision, including the substantial drop in B/Yamagata cases amid the COVID-19 pandemic and the absence of isolated or sequenced B/Yamagata viruses since March 2020.
We’re on the Same Page
In this context, NSH is also on the same page with ‘Lancet’, and echoes the same opinion on the exclusion of B/Yamagata from seasonal influenza vaccines carries significant implications, both in terms of vaccine formulation and distribution strategies. Historically, quadrivalent vaccines containing both B/Yamagata and B/Victoria lineages were used to mitigate the risk of mismatch between circulating influenza B viruses and vaccine strains. However, with the decline of B/Yamagata transmission, trivalent vaccines may now emerge as the preferred choice.
The adoption of trivalent vaccines could lead to a simplification of influenza vaccine campaigns, potentially resulting in cost savings and increased accessibility. However, manufacturers face a challenging decision regarding whether to focus solely on trivalent vaccines or to update quadrivalent formulations with a different influenza A lineage instead of B/Yamagata. Such an update would require modifying potency assays and potentially conducting clinical trials to ensure the effectiveness of the revised quadrivalent vaccines.
The editorial rightly points out that continued surveillance for B/Yamagata is crucial to detect any possible resurgence of this lineage. While WHO’s recommendation pertains to the Southern Hemisphere, it is anticipated that similar changes may be recommended for the Northern Hemisphere as well, which would necessitate a global reassessment of influenza vaccination strategies.
The observations also raise questions about the impact of this shake-up on the development of new influenza vaccines. Manufacturers with ongoing clinical trials of quadrivalent mRNA vaccines, such as Moderna and Pfizer, may need to reassess their formulations to exclude B/Yamagata. Additionally, Novavax’s trials with recombinant haemagglutinin proteins from four influenza strains, including B/Yamagata, may need to be revisited.
‘The Lancet’ Infectious Diseases editorial presents a thorough examination of the influenza vaccine shake-up prompted by the exclusion of the B/Yamagata lineage from future vaccines. The decision made by WHO reflects the unprecedented circumstances faced during the COVID-19 pandemic and emphasizes the dynamic nature of influenza control measures. While challenges and uncertainties lie ahead, this shake-up presents an opportunity for simplifying vaccination campaigns, reducing costs, and exploring alternative vaccine formulations to ensure broader coverage against influenza.
