Sustainable demand for seasonal influenza vaccines is a component of national security strategies for pandemic preparedness. However, the ongoing COVID-19 pandemic has revealed many weaknesses in the capacity of countries to design and execute sustainable vaccination programs. An influenza pandemic remains a global threat and yet there is no global monitoring system for assessing progress towards influenza vaccination coverage targets. The International Federation of Pharmaceutical Manufacturers and Associations’ (IFPMA) Influenza Vaccine Supply International Task Force (IVS) developed a survey method in 2008 to estimate seasonal influenza vaccination coverage rates, which in turn serves as a crude estimate of pandemic preparedness. It provides evidence to guide expanded efforts for pandemic preparedness, specifically for increasing COVID-19 vaccine immunization levels. Furthermore, the results presented herein serve as a proxy for assessing the state of pandemic preparedness at a global and regional level. This paper adds data from 2018 and 2019 to the previous analyses. The current data show an upward or stable global trend in seasonal influenza vaccine dose distributed per 1,000 population with a 7% increase between 2017 and 2018 and 6% increase between 2018 and 2019. However, considerable regional inequities in access to vaccine persist. Three regions, Africa, the Middle-east, and Southeast Asia together account for 50% of the global population but only 6% of distributed seasonal influenza vaccine doses. This is an important finding in the context of the ongoing COVID-19 pandemic, as distribution of influenza vaccine doses in many ways reflects access to COVID-19 vaccines. Moreover, improving seasonal vaccine uptake rates is critical for optimizing the annual benefits by reducing the huge annual influenza-associated societal burdens and by providing protection to vulnerable individuals against serious complications from seasonal influenza infections.

The coronavirus disease 2019 (COVID-19) pandemic has prompted rapid investigation and deployment of vaccine platforms never before used to combat human disease. The severe impact on the health system and the high economic cost of non-pharmaceutical interventions, such as lockdowns and international border closures employed to mitigate the spread of COVID-19 prior to the arrival of effective vaccines, have led to calls for development and deployment of novel vaccine technologies as part of a “100-day response ambition” for the next pandemic. Prior to COVID-19, all of the pandemics (excluding HIV) in the past century have been due to influenza viruses, and influenza remains one of the most likely future pandemic threats along with new coronaviruses. New and emerging vaccine platforms are likely to play an important role in combatting the next pandemic. However, the existing well-established, proven platforms for seasonal and pandemic influenza manufacturing will also continue to be utilized to rapidly address the next influenza threat. The field of influenza vaccine manufacturing has a long history of successes, including approval of vaccines within approximately 100 days after WHO declaration of the A(H1N1) 2009 influenza pandemic. Moreover, many advances in vaccine science and manufacturing capabilities have been made in the past decade to optimize a rapid and timely response should a new influenza pandemic threat emerge.

Seasonal influenza vaccines have the potential to prevent significant morbidity and mortality and the World Health Organization recommends that all countries consider implementing seasonal influenza immunization programmes. These provide invaluable supports to pandemic response, whether through the utilization of influenza epidemiological surveillance systems such as the WHO Global Influenza Surveillance and Response System (GISRS) or RespiMart, by imparting countries with ability to scale up vaccination in response to pandemics, and by contributing to the global production capacity for vaccines. During the COVID-19 pandemic, countries with higher influenza vaccination coverage also achieved higher COVID-19 vaccination coverage. But vaccine hesitancy and complacency are preventing optimal benefits from seasonal influenza vaccination. In 2008, the International Federation of Pharmaceutical Manufacturers and Associations' (IFPMA) Influenza Vaccine Supply International Task Force (IVS) developed a survey method to estimate vaccination coverage rates. The present survey, for 2022 and 2023, highlights that the vast improvements in seasonal influenza vaccination coverage rates achieved during 2020 and 2021 are regrettably not being sustained. Twenty-seven fewer countries in 2022 and 29 fewer countries in 2023 distributed any doses of seasonal influenza than in the peak year for number of countries, 2011. In 2023 there were 17 % fewer vaccine doses distributed globally than in the peak year, 2020. Only 33 of 195 countries achieved the hurdle rate in 2023, defined as number of doses distributed to ≥15.9 % of the population. Governments can strengthen performance of their seasonal influenza vaccination programs with a few key actions. Because immunization returns up to 19 times the cost in societal value, it is critical for governments to identify and implement appropriate countermeasures to vaccine hesitancy and complacency including vaccine advocacy, communications, and communication training for Healthcare Workers. Governments' challenge is to sustain resolve beyond the public health emergency of COVID-19.

This commentary provides an overview of the development of a zoonotic influenza vaccine, in response to the emergence of an H5N1 subtype virus from clade 2.3.4.4b in mid-2020. When development was initiated, the World Health Organization (WHO) had recommended four candidate vaccine viruses; the A/Astrakhan/3212/2020-like strain was selected as it provided good coverage of circulating viruses and, critically, was available. To facilitate regulatory approval, the licence of an existing zoonotic vaccine, Aflunov (A/turkey/Turkey/01/2005)—a pre-pandemic monovalent A/H5N1 adjuvanted with MF59 and manufactured using the egg-based platform—was duplicated, with the plan to submit a variation to the duplicate licence for the strain update. This was supported by a ferret immunogenicity study using pseudoviruses (allowing the work to be conducted at a lower biosafety level), in conjunction with clinical data from the original Aflunov licence application, and a US study (NCT05874713) on another candidate zoonotic vaccine manufactured using the cell-based platform. Qualification batches for characterisation studies were manufactured at-risk, until calibrated, homologous reagents were available, and the final product release and stability studies were conducted, with rolling provision of stability data to health authorities. The vaccine was initially approved with a shorter shelf-life, allowing early distribution in certain countries, with later extension of the shelf-life once data became available. In terms of procurement and logistics, early consultation between the European Commission and EU member states resulted in the award of a Framework Contract for the initial supply of 665,000 doses to 15 states. Learnings from the development of this vaccine may help to improve pandemic readiness in the future.