The report, Influenza Vaccine Strategies for Broad Global Access, has claimed that of the approximately 13 billion doses needed in an outbreak - to provide coverage with two doses of vaccine for the entire world population - only 2.4 billion doses could be manufactured within a six-month time frame.
According to the report preparers, non-profit global health organisation PATH and management consultancy Oliver Wyman, in collaboration with the World Health Organisation (WHO), this would be the "best-case scenario" given the existing vaccine production capacity and the use of inactivated egg-based vaccines.
"Thus, 'real-time' access, in which vaccine production is begun at the time of the outbreak and is based on the actual pandemic strain, is not a viable approach in the near-term to providing global coverage," the report said.
"Moreover, because most manufacturing capacity is in developed countries, it is unlikely that the near-term supply will be available for export to low-resource countries."
Due to limited infrastructure and technology constraints, the report said a short-term time-frame of less than five years would not provide enough time to increase capacity, requiring instead pre-pandemic measures, which are already in place, such as stockpiling, to bear the brunt of the shortfall.
But even if excess manufacturing capacity exists and is used relative to seasonal demand, dose-sparing adjuvants are incorporated into formulations, and faster manufacturing technologies are taken up, the report said: "In the best-case scenario, it would take four years to satisfy the global need through pre-pandemic measures. In a worst-case scenario, however, less than 20 percent of the global population would be covered by 2013."
A long-term time-frame of more than five years was much rosier, with newer technologies, such as live attenuated and recombinant technologies, providing the potential for real-time access based on the actual pandemic strain, while also being at a more affordable cost.
"Leveraging these technologies for real-time access in the longer term would require the creation of new bulk production facilities globally. We estimate that four to eight bulk production facilities using these technologies, located in the developing world, would be appropriate to balance investment requirements and risk diversification objectives," the report said.
The authors estimated the investment to implement both short and long-term strategies would be in the range of $2bn to $10bn. This did not include profit margins for vaccine manufacturers, nor vaccine administration costs.
The report suggested that both short-term and long-term strategies be implemented in parallel.
"While the situation at first glance looks extremely challenging, there are real solutions that can be pursued to close the gap," Oliver Wyman director Andrew Pasternak said in a statement.
"Successfully realising these solutions, however, will require both global commitment and careful co-ordination among key stakeholders, with WHO playing a central role."
The report conclusions were presented at a WHO consultation of global experts on pandemic influenza vaccines last month.
The WHO began a four-day intergovernmental meeting on pandemic influenza preparedness in Geneva yesterday. Topics would include sharing flu virus samples and increased access to vaccines.
Some experts estimate that a pandemic outbreak of influenza could result in more than 100 million deaths worldwide.
The report can be accessed here .
