Globally, seasonal influenza is thought to attack 5-10% of adults and 20-30% of children. This translates to roughly 3-5 million cases and 250,000-500,000 deaths annually.
But these numbers are an approximation; because of minimal surveillance data available from low- and middle-income countries, global estimates are often extrapolations of data from the US or other high-income countries with a long history of seasonal influenza surveillance.
PIVI partners exclusively with low- and middle-income countries and while the burden of disease from seasonal influenza in these countries is not well delineated, estimates indicate that a large percent of child deaths associated with influenza occur in developing countries. Statistics from the WHO’s Africa Flu Alliance highlight why it is so important to boost seasonal influenza vaccination efforts in low- and middle-income countries: “in 2002 an influenza outbreak in Madagascar [a low-income country] had a case fatality rate of 3% as compared to <.01% in other influenza pandemics. The majority of deaths occurred in young children.” Aside from directly affecting individuals through illness and even loss of life, influenza can also have wider-reaching effects on social systems. Influenza can hurt economies by increasing the amount of healthcare utilized (and therefore the total dollars spent on healthcare), straining the resources of healthcare providers, reducing worker productivity, and causing absenteeism. It is estimated that in the US, the average annual cost of seasonal influenza is approximately $27 billion. In low- and middle-income countries, such a burden puts additional pressure on already strained individuals and systems.
A challenge any influenza-oriented program faces in working in low- and middle-income countries is the lack of information about how seasonal influenza affects those countries. In order to estimate and understand the impact that seasonal influenza has worldwide and in individual countries, disease surveillance systems are necessary. Surveillance data help to paint a picture of how flu behaves in different countries and regions and, in turn, can be used to guide countries (and international bodies, like the WHO) as they develop policies and procedures related to this vaccine-preventable disease. Many WHO member countries now have a WHO-designated National Influenza Centre (NIC) which gathers and reports influenza surveillance data.
Barriers to vaccination
Why has it taken so many countries so long to start conducting influenza surveillance? There are several reasons, all related to the fact that many countries either do not offer national influenza immunization programs or have only just begun to offer such programs in relatively recent history. Some of the barriers to vaccination campaigns (and vaccination itself) are: a low perception among the public of the risk of contracting the flu, questions about vaccine effectiveness, questions about vaccine effects, the lack of a national policy regarding influenza vaccination, and the cost and availability of the vaccine.
National policies regarding influenza vaccination can affect both individuals and manufacturers. Policies can shape the public’s risk perception by affirming that influenza vaccination is an essential part of maintaining a healthy population. National policies require one additional element though, in order to successfully create demand and protect populations: follow through. A WHO resolution adopted in 2003 recommended that all member states “increase influenza vaccination coverage of all people at high risk and to attain coverage of 75% among the elderly by 2010.” Yet a 2014 report on the status of this recommendation found that, of those European Region member states with a national seasonal flu policy, a gap existed “between recommendations and implementation (vaccine uptake).” The report also found gaps “between recommendations and availability of mechanisms to monitor uptake.” Ultimately, WHO concluded: “The lack of efficient vaccination coverage assessment in target groups prevents accurate monitoring of interventions and evaluation of the effectiveness of seasonal vaccination programs.” This lack of data only serves to perpetuate the dearth of information available about the role of seasonal flu in many countries.
A lack of data regarding the effects of seasonal influenza in low- and middle-income countries should not be considered an indication that seasonal influenza is not affecting these countries. Many estimates suggest that, on the contrary, these countries are likely experiencing worse outcomes and a higher disease burden due to seasonal influenza. The absence of data is something PIVI is working to overcome. When PIVI makes a contribution to a partner country, the goal is not only to provide vaccine in order to protect high-risk individuals from the flu, but also to assist partner countries with the development or growth of their disease surveillance and disease preparedness infrastructure. Partner countries keep track of how the vaccine doses are distributed and post-implementation evaluations help the country – and PIVI – learn more about participants’ attitudes towards the vaccine and experiences with it (eg. adverse events following immunization). That information can then contribute to the larger body of knowledge about seasonal influenza as well as help partner countries better prepare for the next flu season.
World Health Organization, Seasonal Influenza
World Health Organization, Africa Flu Alliance
Asia-Pacific Alliance for the Control of Influenza
World Health Organization: Evaluation of seasonal influenza vaccination policies and coverage in the WHO European Region