This year, we observe the 100th anniversary of the start of the 1918 influenza pandemic, which killed at least 50 million people worldwide. While the great pandemic of 1918 and its human and economic costs may seem remote, hundreds of thousands of people still die each year from annual, seasonal influenza and the next influenza pandemic could emerge at any time. The best defense against the ongoing burden of seasonal epidemics and the threat of the next pandemic, we need to solve two problems: a science problem and a capacity problem.

The science problem is to create better influenza vaccines. While, vaccines against influenza have been the foundation of influenza control programs for decades, for both pandemics and seasonal epidemics, current influenza vaccines are moderately effective, need semi-annual updates to keep up with rapidly mutating viruses in nature, and require substantial time for production that may reduce their utility during a fast-moving pandemic. Substantial work is underway towards more effective seasonal influenza vaccines that can be produced more quickly, with notable successes in recent years. Additionally, investments are increasing to create game-changing vaccines that could prevent any type of flu one encounters (including a pandemic strain) and could be given less often than annually. The science problem here is a difficult one that will take many years, but is increasingly a focus of scientists worldwide.

However, as the work to develop better vaccines progresses, it is essential that countries develop the programs to deliver and administer the vaccines. This is the “capacity” problem, and while not glamorous, may be even more urgent. Even the best vaccines require national systems to guarantee their timely delivery and use once they are created. During the 2009 pandemic influenza response, countries that had existing seasonal influenza programs were able to deliver the vaccines to their target populations more rapidly and effectively than those countries without such programs in place. This clearly illustrated the importance of building the regulatory, policy development, planning, delivery and evaluation systems in all countries before a pandemic, so that the vaccine will get quickly from the production line into the arms of those most in need.

Tremendous improvements in national immunization programs have taken place since the advent of the Expanded Programme on Immunizations in the early 1980s, and strengthened by investments made through the Global Alliance for Vaccines and Immunizations. However, these investments have focused primarily on childhood vaccination programs. Pandemic influenza vaccine target groups will likely to extend beyond children to health care workers, elderly adults, emergency responders and those with chronic diseases that put them at high risk of severe disease. Most low-income countries, and many middle-income countries, have no existing programs to deliver vaccines to these groups. Absence of these programs will result in critical delays in getting the vaccines to those most in need, reducing the value of even the best vaccine.

The best foundation for an effective system to respond to the next pandemic is a robust, seasonal influenza immunization program in all countries. Seasonal influenza vaccination programs are practiced annually, are usually carried out in national campaigns, and focus on groups (e.g., health care workers) that are likely to be targets for vaccines against many of the emerging threats, such as Ebola.

All of these qualities are ideal for ensuring rapid and effective response to future epidemics and pandemics. Programs such as the Partnership for Influenza Vaccine Introduction (PIVI) and WHO’s Pandemic Influenza Preparedness Plan will contribute to strengthening these programs. Building routine seasonal influenza vaccination programs can provide a country the annual benefits of reducing their influenza burden, and also build critical capacity to protect their populations from the next pandemic or other emerging epidemic threats. This work needs to expand and accelerate in parallel with the development of better vaccines, given the unpredictable timing of the next great pandemic.