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Pandemic influenza vaccines

Introduction

WHO/Garry Smyth

The last of the previous century's three influenza pandemics took place in 1968.

• Over the past several years, human cases of H5N1 (bird flu) virus began occurring in an expanded geographical range of countries.

• In April 2009, cases of a new influenza A (H1N1) virus, came to the attention of public health authorities. This latter virus, which contains genetic material from viruses circulating in pigs, birds and humans, is being transmitted from humans to humans. On 27 April 2009, the World Health Organization raised the pandemic alert level from three to four. Two days later, this level was increased to five due to sustained community level outbreaks in two or more countries in one WHO region.

• On 11 June 2009, WHO, noting sustained community-level outbreaks of influenza A (H1N1) in at least one other country in other WHO regions, raised the alert level to its maximum (six), thereby declaring an influenza A (H1N1) pandemic.

Development and timeline

Vaccines are one of the most effective ways to protect people during influenza epidemics and pandemics. Work is underway to develop a vaccine for the pandemic influenza A(H1N1) virus. The first doses are expected to be available in five to six months from the identification of the pandemic strain, i.e. Fall 2009.

• Pandemic influenza vaccine manufacturing process and timeline

Production and access

In the past two years, pandemic influenza vaccine production capacity has sharply increased. However, the world still lacks the manufacturing capacity to meet potential global pandemic influenza vaccine demand.

While no precise estimate is available today, it is thought that global manufacturing capacity for influenza A (H1N1) vaccines is at least 1 to 2 billion doses per year and could be as many as 4.9 billion doses per year, provided certain conditions are met.

In 2006, WHO launched the Global pandemic influenza action plan to increase vaccine supply (GAP [pdf 520kb] ), a US$ 10 billion effort over 10 years. It aims to ensure equitable access for all countries to vaccine in case of a pandemic. Strategies to do this include expanding global production capacity through an increase in demand for seasonal influenza vaccine (thereby relying on market forces) and enabling countries to establish their own influenza vaccine production facilities through transfer of technology. Activities are ongoing to fill current gaps.