Special attention was given to the development of possible universal influenza vaccines, given that the Global Vaccine Action Plan calls for at least one licensed universal influenza vaccine by 2020
February 26, 2022
Special attention was given to the development of possible universal influenza vaccines, given that the Global Vaccine Action Plan calls for at least one licensed universal influenza vaccine by 2020. vaccine, Seasonal NECA influenza vaccine NECA 1.?Introduction Circulating influenza strains undergo antigenic drift, and occasionally shift, over time. These phenomena, coupled with waning immunity post vaccination, necessitate the annual review and frequent revisions of seasonal influenza vaccines and yearly vaccination. The burden of influenza disease (reviewed by WHO in 2012 ) and its socio-economic impact, is likely to increase during influenza pandemics, when antigenically shifted viruses infect susceptible human populations that have little or no virus-specific antibody from prior infection or vaccination. Research is needed to develop influenza vaccines that produce broadly protective and long-lasting immune responses to obviate the need for annual immunization to prevent seasonal influenza and to produce a new vaccine to prevent disease when a pandemic virus emerges. In May 2014, the World Health Organization (WHO) held its second integrated meeting on Influenza vaccines that induce broadly protective and long-lasting immune responses. Around 100 invited experts from academia, the vaccine industry, research and development funders, and regulatory and public health agencies attended the meeting. Areas covered included correlates of protection in natural influenza-virus infection  and vaccine-induced immunity, new approaches to influenza-vaccine design and production, and novel routes of vaccine administration. A timely focus was on how this knowledge could be applied to seasonal influenza and also emerging viruses with pandemic potential such as influenza A (H7N9), currently causing outbreaks in humans in China. This report highlights some of the topics discussed and provides an update on studies published since the report of the previous meeting . 2.?Goals of universal or universal-like influenza vaccines Since the first WHO meeting on this topic in January 2013, the Global Vaccine Action Plan , which includes a target for developing a universal influenza vaccine by 2020, was approved by the World Health Assembly. There remains debate however, about what constitutes a universal influenza vaccine. A universal influenza vaccine is generally considered to be one that elicits a broader immune response to protect against a greater range of influenza viruses and for NECA longer than current influenza vaccines, obviating the need for annual updates of vaccine formulations. At the most optimistic extreme, this would be an entirely new type of influenza vaccine where one dose or course would provide life-long safety against all influenza disease infections, without requiring any intervening improving doses. In Rabbit Polyclonal to Bax (phospho-Thr167) the additional extreme, progress may involve incremental improvements on the status quo, whereby a universal-like vaccine would produce broader or longer lasting immunity compared to current vaccines, but would still require boosting doses (though not yearly) and would not be expected to protect against all influenza A disease subtypes. For example, existing influenza vaccines could be combined with fresh approaches to produce vaccines, and/or vaccination strategies that induce broader immunity to protect against more antigenically drifted influenza strains and/or for a longer duration. Some of these methods could reduce the need for annual re-vaccination and/or increase vaccine performance in years where there is a poor match between vaccine strains and circulating disease. The development of broadly protecting (across all or many subtypes of influenza A viruses) and long-acting influenza vaccines was widely agreed to become extremely important but also very challenging. Replacing annual influenza vaccination with less-frequent re-vaccination could have important manufacturing and programmatic implications, especially for low-resource countries. An important part of the conditioning of general public and private sector influenza vaccine developing capacity has been to increase the surge capacity for pandemic vaccine production [5,6]. In 2011, global production of seasonal influenza vaccines was at least 620 million doses . However, if the annual demand for influenza vaccines was reduced through the development of universal-like vaccines that induce broader and longer lasting immunity against seasonal NECA influenza viruses, this could lead to a reduction in global capacity to respond to an growing influenza pandemic. 3.?Measuring immune responses: correlates of protection Increasing the.