Pan-canadian public health network council report and policy recommendations on the use of antivirals for prophylaxis during an influenza pandemic

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Annex 3.6–International Trends Regarding Antivirals for Prophylaxis

Submitted by:
Jill Sciberras
Senior Epidemiologist, Immunization and Respiratory Infections Division, PHAC

Intended for: Task Group on Antivirals for Prophylaxis

Summary

Two of the eight countries examined (i.e., US, Mexico, UK, France, Germany, Japan, Australia and Italy) have indicated that at this time the primary use of their antiviral stockpiles is expected to be prophylactic indications. These two countries are quite different from each other. One has the smallest per capita stockpile of the eight countries and therefore has chosen to focus on post-exposure prophylaxis of health care workers and other first responders due to their limited supply. This country has not committed to using antivirals as part of a containment strategy and currently does not have enough antivirals to engage in a treatment strategy. The other country has one of the highest per capita stockpiles. This country is intently focused on containment with the objective of delaying spread of the virus until a vaccine becomes available. If containment fails, then the focus will shift to preventing infection among essential service providers and those whose work puts them at high risk of exposure to and spreading of the pandemic virus.

Information sources

In addition to Canada, the following countries completed a questionnaire that was issued in October 2006 as part of the activities of the Global Health Security Action Group(GHSAG):

• United States
• Mexico
• United Kingdom
• France
• Germany
• Japan

This survey asked a number of questions regarding the status of pandemic planning activities in these countries, including questions regarding antiviral stockpiles and anticipated antiviral use during a pandemic. Due to the confidential nature of the questionnaire only summary data is provided at this time.

This type of information was also sought from the national plans for Australia and Italy, which are currently posted on the internet. The analysis below is based on information publicly available from these countries.

Antiviral stocks

Of the 8 countries (excluding Canada) listed above:

• All countries have focused on oseltamivir for stockpiling purposes (two indicate that they have stockpiled some doses in paediatric formulation);
• Four countries have stockpiles containing zanamivir, (for one other country it is unclear since only “neuraminidase inhibitors” are listed), and one additional country has indicated intent to purchase zanamivir;
• One country has some rimantadine in their stockpile, while no countries indicated that amantadine has been stockpiled;
• One country has indicated that their stockpile is complete (i.e., current supplies match the latest target for their stockpile).

Antiviral use

The following is based on information from the 8 countries listed previously.

• Six of the eight countries have indicated that the focus of their antiviral strategy will be to use the stockpiled antivirals for treatment of cases during the pandemic.
• None of the six countries with treatment-focused strategies have committed to providing antivirals for prophylaxis, however, five have indicated that use for post-exposure prophylaxis is under discussion. One has indicated that prophylaxis during the pandemic period is “of little use” and “increases the risk of viral resistant strains and…collateral effects.”
• Where prophylaxis is being discussed, the focus is on post-exposure prophylaxis for health care workers and for household contacts of cases.
• Prophylaxis use during a “containment” effort (e.g., during phase 4-5 or even “early in the pandemic”) is being planned for or considered in all six countries with treatment-focused strategies.
• One of the countries that have not included “treatment” as part of their current strategy is the one with the lowest per capita supply. This country has indicated that until there is a decision to increase the supply their focus will be on post-exposure prophylaxis of health care workers and other first responders only.
• The other country without a clear “treatment-focus” has indicated that they are intending to use some (10%) of their stockpile to evaluate the treatment strategy in advance of the pandemic – which will further inform decision making. This country has committed to treating cases as part of a containment strategy, but has indicated that during the pandemic the focus will be on pre and post exposure prophylaxis (based on assessment of sustained risk) of those who provide essential services for the community and whose work puts them at high risk of exposure to, and spreading of, the pandemic virus. This is the only country of the 8 examined which has indicated continuous (pre-exposure) prophylaxis as part of their antiviral strategy.

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