- © 2005 Canadian Medical Association or its licensors
H5N1 is the best candidate flu strain for an expected influenza pandemic, but countries around the globe are ill prepared to manufacture it, the World Health Organization is warning.
“There is currently too little momentum in the development of influenza pandemic vaccine,” says Dr. Klaus Stöhr, coordinator of the WHO Global Influenza Programme. “There is a need to raise the profile of pandemic preparedness as a matter of national security planning.”
Countries have a narrow window of opportunity to prepare before a pandemic strikes, Stöhr says.
An influenza pandemic involves a novel strain of influenza that has not circulated among humans. Based on the historic emergence of influenza pandemics — on average every 25 years — the world is overdue for another one. The last one occurred in 1968–69.
WHO has been hosting meetings in Geneva to focus specifically on encouraging more manufacturing and clinical testing of potential vaccines. The organization is also urging governments to finance vaccine development and to plan the logistics of a vaccination ground war against whichever virus emerges as the pandemic strain.
Although no one knows for certain what strain of influenza will prevail, the WHO is keeping a close eye on emergent avian flu strains in Asia. “We have in Asia an H5N1 virus which is ready to cause a pandemic,” Stöhr said after the WHO meeting on vaccine development in November.
WHO wants governments to demonstrate their commitment to preparing for a pandemic by investing in the development and clinical trials of potential vaccines, particularly “mock” vaccines, or “seed” pandemic candidates, which can be tailored at the last minute to the specific pandemic strain. Most pharmaceutical companies won't invest in these seed vaccines because they won't get a return unless a pandemic occurs, Stöhr says.
“The single most important matter now is that clinical testing start. And that costs money,” he says.
At the moment, only the US and Japanese governments have agreed to finance clinical trials of potential vaccines.
Canada is one of only a few countries with a pandemic plan and a contract with a domestic supplier to produce enough vaccine for its entire population — but there are significant gaps in our preparedness, health officials acknowledge.
Cabinet has not yet seen or approved a proposal to invest in the development of a mock pandemic vaccine. “One of the key areas and key challenges is being able to make the case for doing that to government,” says Dr. Arlene King, the Public Health Agency's director of immunization and respiratory infectious diseases division.
Dr. Carolyn Bennett, secretary of state for public health, would not discuss the cost of this development, but said her agency is working on a Memorandum to Cabinet.
Health Minister Ujjal Dosanjh supports the development of a seed vaccine. “Politicians should always be guided by science in these situations,” he said in a statement to CMAJ. “If the Public Health Agency recommends this approach I'm prepared to support it.”
Currently, Canada is committed to a $325-million contract over 10 years with ID Biomedical in Vancouver to supply vaccine in the event of a pandemic. That contract requires the company to keep all the raw materials on hand in order to produce a pandemic vaccine once the critical influenza strain is identified, says Dean Linden, a spokesman for ID Biomedical. It would then take the company 7 months to produce a vaccine — not including regulatory approval or clinical trials. Even then, the vaccine would be produced in batches. The federal government also spends $7 million annually to ensure a supply of fertilized eggs (for incubating a vaccine) and equipment, says King.
However, ID Biomedical cannot work on a mock vaccine because it doesn't have a manufacturing plant with the level of containment required to handle an active virus. In fact, no one in Canada does, says King. It would take several months to build such a facility, before even beginning to manufacture a vaccine.
Dr. Frank Plummer, head of the National Microbiology Laboratory, says Canada needs more rapid vaccine development capacity. The issue of manufacturing capacity is critical. “We need to look at not only vaccines for the H5N1, but also strategies that might allow us to more rapidly develop a vaccine for any pandemic, whatever type it happens to be,” he told CMAJ.
Using current vaccine types and manufacturing facilities, it could take “about a year to get enough vaccine for the Canadian population,” Plummer says. “We need to do everything we can to shorten this.”
King acknowledges that vaccines, “the cornerstone of our pandemic response … will not be available at the beginning of a pandemic.”
“Consequently, we are going to have to rely on other measures to try to mitigate or to lessen the harm caused by the emergence of a pandemic virus,” she says.
One of those measures is the use of antiviral drugs, both to treat influenza and as a prophylactic for health care workers and others considered at high risk or deemed to provide essential services. But Canada does not have enough antiviral drugs stockpiled to meet that initial need.
“We do have a limited stockpile of antivirals in Canada, and this issue of having a larger stockpile of antivirals is something that is under active and urgent consideration by the Public Health Agency of Canada,” King says.