Jan 23, 2008 (CIDRAP News) – Antiviral medications and vaccines are two tools that many government and health officials hope will stall the spread of an influenza pandemic, but each strategy has daunting challenges, according to a new report from Congress's Government Accountability Office (GAO).
The report, Influenza Pandemic: Efforts Under Way to Address Constraints on Using Antivirals and Vaccines to Forestall a Pandemic, was requested by four members of Congress who head various health and homeland security committees. It was released this week on the GAO's Web site.
In its report, the GAO acknowledges that national governments and international organizations are working with pharmaceutical manufacturers to expand global production of antivirals and vaccines. However, it cites a US Department of Health and Human Services (HHS) caveat that a pandemic vaccine might play little role in the early phases of a pandemic, because it will take 20 to 23 weeks to develop and produce a targeted vaccine. Also, the GAO says it would be difficult to quickly expand antiviral production, because of the need to build new facilities, obtain production materials, and gain regulatory approval.
Weaknesses in international surveillance systems are hampering the detection of influenza outbreaks, which the GAO says could limit the ability to promptly administer or develop antivirals or vaccines.
"WHO has noted that to increase the likelihood of successfully forestalling the onset of a pandemic, surveillance in affected countries needs to improve, particularly concerning the capacity to detect clusters of cases closely related in time and place," the report states. "If early signals are not identified, the opportunity for preemptive action will be missed."
Indonesia's reluctance to share human H5N1 samples with the international community, because of its concerns that the country will not have access to the resulting pandemic vaccines, has further weakened global surveillance efforts in humans, the GAO authors write.
Likewise, surveillance of influenza in animals also has shortcomings, the GAO reports. For example, outbreak definitions and reporting methods vary by country, and some countries, such as Djibouti and Uganda, lack the capacity to collect, transport, or identify animal influenza samples.
The GAO notes that the WHO's revised International Health Regulations, which for most countries took effect in June 2007, are aimed at improving global surveillance. The regulations spell out basic public health capacities countries must have and set a June 2012 deadline for nations to develop them. Also, the GAO lauds the US National Institutes of Health (NIH) for its support of influenza research and surveillance and highlights the Centers for Disease Control and Prevention's (CDC's) role in characterizing and tracking the global spread of the H5N1 virus.
Nonexistent or poor distribution networks in many countries will hamper the release of antiviral or vaccine stockpiles, the GAO warns, citing one of its earlier investigations that found 10 of 17 countries reviewed didn't have plans for mobilizing medical countermeasure stockpiles. A lack of distribution networks is particularly an obstacle to antiviral utilization, because experts recommend that the drugs be taken within 48 hours of symptom onset, the GAO says.
To best utilize antivirals and vaccines, health officials need a reliable, fast diagnostic test to identify patients who have H5N1 infections, the report states. Though the CDC awarded four companies $11.4 million to develop new diagnostic tests, the agency estimates that approval and commercialization of the devices will take 2 or 3 years.
More international support for clinical trials is needed to spur the development and evaluation of antivirals and vaccines, the GAO says. The report notes that most of the support for these studies comes from only four countries: the United States, Australia, Japan, and the United Kingdom.
Health officials have hoped that establishing greater global demand for seasonal influenza vaccines could help build greater vaccine production capacity, but the GAO says some countries are too overwhelmed to participate.
"Seasonal influenza programs compete with many other public health priorities for limited budgets in developing countries," the report states. "Citing Vietnam as an example, NIH officials told us that countries may have been too overwhelmed with H5N1 outbreaks to accept offers of assistance to develop vaccine production infrastructure."
The WHO, HHS, and the US State Department were asked to review the GAO report in draft form. The GAO said the WHO commented in an e-mail that the report was "comprehensive and useful." HHS, in a letter accompanying the GAO report, emphasized that vaccines and antivirals are only one part of the government's pandemic response plan. The State Department and HHS both questioned the GAO's use of the term "forestall" when referring to using antivirals and vaccines during a pandemic.
"While preventing a pandemic from occurring is the goal that all strive for, whether it can actually be achieved is not known," wrote Vincent J. Ventimiglia, assistant secretary for legislation at HHS, in a letter accompanying the report.
However, the GAO said its use of the word "forestall" is consistent with the WHO's usage of the term.
January 2008 GAO report
CIDRAP News article series published in 2007: "THE PANDEMIC VACCINE PUZZLE"