- Pandemic influenza presents significant public health challenges and countries need to prepare in advance.
- Vaccines represent an essential component of public health policy around the world.
- Seasonal vaccination programs play an important role in safeguarding vaccine production to enhance the health infrastructure for pandemic management.
- The research-based pharmaceutical industry has an essential role to play when called on by the public health authorities, as was highlighted during the 2009 H1N1 pandemic.
- R&D industry is committed to researching and developing safe and effective pandemic influenza vaccines.
Typical seasonal influenza outbreaks are caused by subtypes of influenza viruses that have previously circulated among the general public. Because of this previous exposure, many people are able to mount at least a partial immune response against the illness. Despite this, between 250,000 to 500,000 people die each year worldwide due to influenza.
By contrast, about once every 30-40 years, pandemic influenza occurs when a strain of influenza virus that has never circulated among people emerges in the population. There is no or little pre-existing natural immunity to these viruses. Thus, pandemic influenza can quickly spread around the world and lead to high morbidity and mortality. (CDC Pandemic Influenza, Pandemic Flu Questions and Answers, January 17, 2006)
In the event of a pandemic, seasonal vaccine production plants are used to manufacture pandemic vaccine. In anticipation of an emerging influenza pandemic, vaccine manufacturers around the world invested in expanding their existing production facilities or building new plants as extensions, in order to increase global influenza vaccine production capacity within the existing facilities. Since it is equally important to stimulate vaccine production in low- and middle income countries, individual vaccine manufacturers increasingly contribute to technology transfer to help build and develop local influenza vaccine production in those countries. Since large populations require vaccines to protect against a new pandemic virus strain in the shortest possible time, regulatory authorities have developed processes to fast-track the appraisal of pandemic vaccines, to allow their rapid use without compromising safety. These procedures build on the extensive experience gained with seasonal influenza vaccines over the last 60 years, and the results of clinical trials conducted on a range of prototype pandemic vaccines and new H1N1 vaccines. As a result, a comprehensive range of measures is in place to review and monitor the safety of pandemic vaccines. These include regulatory assessment, ongoing clinical testing and wide-scale surveillance as part of broader vaccine use.
Prior to 2009, the most recent influenza pandemic was in 1968. That flu contained a combination of genes from avian and human influenza strains. It spread from Asia to Europe and North America within three months and ultimately killed an estimated 1 million people worldwide. (WHO Factsheet No. 211, Influenza (Seasonal), April 2009).
But since 1997, global health authorities have watched influenza strain A/H5N1 – otherwise known as “avian flu” – with caution. The assessment was that it posed the greatest potential to become the next pandemic due to sporadic outbreaks of avian flu in Asia and an observed mortality rate of 60 percent.
Nevertheless, a different strain – A/H1N1 – emerged in April 2009 in Mexico. Called “swine flu” because of its genetic similarity to the influenza virus that occurs in pigs, this strain proved capable of human-to-human transmission. By June 11, 2009, the virus had spread beyond the Americas to Asia, Europe and Oceania, prompting WHO officials to declare Phase 6, the highest pandemic alert level. A/H1N1 was considered a global threat.
During the H1N1 2009 pandemic, individual vaccine producers pledged, in total, 166 million doses of H1N1 pandemic vaccines to help meet WHO’s 200 million dose target for developing country supply.
Pandemic Influenza is a worldwide outbreak of a specific influenza virus which affects a large number of people and populations around the world. Influenza A virus subtype H1N1, also known as "swine influenza", was the most recent pandemic influenza outbreak and occurred in 2009.