ARCHIVED: Recommendations: The Management of the National Antiviral Stockpile: Options Report

 

Recommendations for ensure best practices in stockpile management include:

  1. Ensure there is an ongoing mechanism to address ongoing stockpile issues, such as the 2011 expiries, stricter storage requirements, adjustments to population trends, future expert recommendations, and planning for additional storage requirements. This could be done either through establishing national committee with this mandate or adding this as a mandate to a pre-existing national committee.
  2. Establish a national real-time system so that during a pandemic there is the capacity to monitor at local, provincial/territorial and national levels the rate of stockpile depletion.  This information will inform decisions on the utilization/allocation of the NAS at a PT level and provide and triggers for access to the NESS and alerting the AVWG on the need to consider prioritization groups in the light of impending scarcity.
  3. Clarify the federal, provincial, and territorial roles/responsibilities for ongoing and stable funding and management of the stockpiles.
  4. Explore a potential long-term option for maintaining stable drugs in stockpiles past their stated shelf life is an amendment to Canada’s Food and Drugs Act.

Purpose

In June 2008, the Conference of Federal, Provincial and Territorial Deputy Ministers of Health asked the Public Health Network Council (PHNC) to undertake a review of the National Antiviral Stockpile (NAS) and to recommend how to manage expiring antiviral stock.  The Antiviral Stockpile Management Task Group (AVSMTG) was formed with a mandate to review and recommend options for a sustainable stockpile management strategy including short and long term options (Appendix 1 – Terms of Reference for AVSMTG).  The AVSMTG was co-chaired by a provincial/territorial (P/T) government member and a representative of the Public Health Agency of Canada (PHAC).  Members of the AVSMTG included officials from provincial/territorial public health, emergency management, communications, procurement and policy, federal drug regulation and a PHAC legal services representative.

This report documents the research undertaken and the AVSMTG recommendations on the National Antiviral Stockpile with respect to: 

  1. Management of the expiring antivirals in the NAS
  2. Integration of the new technical recommendations on antiviral composition and mix
  3. Best practices for ongoing maintenance of the stockpile

Background

Canadian governments have taken a number of steps to increase Canada’s pandemic influenza preparedness.  The use of antivirals is only one part of a comprehensive approach to pandemic planning.  Antivirals are currently the only specific pharmaceutical intervention that will be available during the initial response to a pandemic until a virus-specific vaccine becomes available. 

Antiviral drugs can be used to treat people who are identified early in their illness.  There is good evidence that antivirals are very effective in reducing complications (duration and severity of illness), and death from influenza, when administered within 48 hours of the onset of symptoms.  Antivirals can also be used to prevent influenza in an individual before or after he or she is exposed to an infected person.  Canadian recommendations on the treatment and limited prophylaxis use of antivirals during a pandemic influenza can be found in the Canadian Pandemic Influenza Plan for the Health Sector, Annex E at: http://www.phac-aspc.gc.ca/cpip-pclcpi/  

Canadian Stockpiles

Federal, provincial and territorial governments have committed to ensuring that Canada has a secure, government-controlled supply of antivirals that can be accessed quickly and equitably in the event of an influenza pandemic.  The use of antivirals will support the following pan-Canadian pandemic goals for pandemic preparedness and response:

  • minimizing serious illness;
  • minimizing societal disruption by reducing the severity of disease;
  • reducing the impact of absenteeism in the critical infrastructure sectors; and
  • possibly reducing the transmission of the influenza virus.

Government purchases of antivirals have largely gone into two stockpile systems in Canada:  the National Emergency Stockpile System and the National Antiviral Stockpile. 

National Emergency Stockpile System (NESS)

The National Emergency Stockpile System (NESS) is a federally owned and funded stockpile of emergency supplies of which the influenza antiviral component was established in 2004.  The NESS is managed by the PHAC.  The antivirals in the NESS are intended for multiple purposes including rapid response to an emerging pandemic and provision of surge capacity in support of P/T efforts to manage pandemic and/or avian influenza. At the time of the creation of the AVSMTG in 2008, the NESS contained an antiviral stockpile of approximately 14 million doses (8 million adult and 2 million paediatric oseltamivir capsules; 4 million zanamivir doses; and 70,000 capsules of amantadine). 

National Antiviral Stockpile (NAS)

The National Antiviral Stockpile (NAS) was created in 2004 to ensure equitable access across Canada to a secure supply of antivirals for pandemic influenza.  The NAS is a provincially/territorially administered supply of antiviral drugs held across the country on a per capita basis in secure temperature-controlled facilities. 

When originally established in 2004, the NAS contained 16 million doses of oseltamivir.  In 2006, the F/P/T Ministers of Health agreed to purchase additional antivirals for the NAS to support an early treatment strategy.  At the time of development of this Report, the NAS contained 55.7 million doses, which will provide enough antivirals to treat all Canadians, including First Nations on-reserve and other federal populations (i.e. federal inmates, federal employees, RCMP officers, etc), who are expected to need it for treatment during an influenza pandemic. 

The size of the NAS stockpile is calculated based on the following Canadian Pandemic Influenza Plan for the Health Sector (CPIP) assumptions:

  • a clinical attack rate of 35% of the population over the course of a pandemic of moderate severity, with
  • half of those clinically ill seeking medical care and receiving antiviral treatment with a standard five day course of treatment. 

Therefore, the NAS contains enough antivirals to treat 17.5% of the total Canadian population.

At the time of the creation of the AVSMTG in 2008, the NAS contained two antivirals approved for use in Canada:  TamifluR (oseltamivir), comprising approximately 90% of the total stockpile, and RelenzaR (zanamivir), comprising approximately 10% of the total stockpile.  By 2009, the National Antiviral Stockpile (NAS) had reached its goal for a national early treatment strategy, and contained 55.7 million ‘doses’ of antivirals comprising:

  • 48.7 M doses of adult (75mg) oseltamivir
  • 5.0 M doses of zanamivir (10mg)
  • 2.0 M capsules1 of paediatric (30mg and 45mg) oseltamivir for children aged 1 to <12

Subsequently, technical recommendations on the NAS composition were made by the expert Antiviral Working Group (AVWG) and are discussed below in the Current Context section of this Report

Antivirals authorized for sale in Canada come in three forms: capsules, liquid, or powder for inhalation.  The antivirals held in the NAS are in the form of oseltamivir capsules (doses for children and adults) or zanamivir powder for inhalation. A more detailed description of the antivirals that are approved in Canada is found in Appendix 2.  Additional scientific or technical information, such as the proposed use(s) of antivirals during a pandemic and authorized indications can be found in the CPIP, Annex E: The Use of Antiviral Drugs during a Pandemic, or in the appropriate product monograph .

Paediatric oseltamivir capsules (30mg and 45mg) became available to Canadian governments in January 2008.  Capsules remain the preferred option to liquid suspension for the stockpile because of their longer shelf-life, smaller storage requirements and the ability to mix them with sweetened liquid, such as regular or sugar-free chocolate syrup, to form a suspension if necessary.

Other stockpiles

Some provincial/territorial governments have chosen to stockpile additional quantities of antivirals.  Some federal government departments also hold a stockpile of antiviral drugs to meet the anticipated needs of their staff. (i.e. Department of National Defence for active duty personnel, Department of Foreign Affairs and International Trade for mission staff overseas).  For the purpose of this Report, subsequent discussion will be limited to the F/P/T antiviral stockpile, or the NAS. 

Expiring stockpiles

All of the oseltamivir that was purchased for the NAS in 2004 had a shelf-life of 5 years from date of manufacture2 .  One of the key issues that needed to be addressed by the AVSMTG was that in the next fiscal year (2009/2010), almost half of the entire NAS, or 28.4 million doses of oseltamivir, will expire (see Table 1).  As displayed in the Table, there will also be a significant quantity of oseltamivir and zanamivir expiring in 2011/2012, which will require future consideration. 

Table 1 – NAS Oseltamivir Expiry Projections, in quantity of doses, by F/Y

Table 1 – NAS Oseltamivir Expiry Projections, in quantity of doses, by F/Y

Changing needs

The Antiviral Working Group (AVWG), an expert advisory group reporting to the Pandemic Influenza Committee (PIC), is mandated to review and assess the composition and size of the national antiviral stockpile.  It makes recommendations from time to time, based on monitoring of population trends, new scientific evidence regarding evidence on resistance to antivirals and disease epidemiology, new technologies, and international trends.  Recent technical recommendations from the AVWG (described below in Current Context) were integrated into the AVSMTG recommendations. 


1 Paediatric doses are prescribed based on weight, and doses range from 30mg to 60mg, depending on weight.  Since paediatric capsules are manufactured in 30 and 45 mg doses, older children (aged 7 to <12) requiring a 60mg dose will take two 30mg capsules (See Appendix 3 – Paediatric Dosage Estimates).  Therefore, it would be inaccurate to describe the paediatric component of the NAS as being “2.0 million doses” since a portion of the 30 mg capsules in the stockpile would be doubled for older children

2 Procurement contracts required a minimum dating of 4.25 years, or 51 months from date of delivery.

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