[Table of Contents]

Volume: 25S5 - August 1999

Proceedings of the National Varicella Consensus Conference
Montreal, Quebec
May 5-7, 1999

Public Health Goals and Objectives for Varicella Control and Vaccine Coverage

Public health goals for varicella control were deliberated within the context of the logistics of program implementation with the currently licensed freezer-stable vaccine. Participants noted that a highly expensive vaccine combined with vaccine delivery costs could divert funds from other public health priorities, thus making the immediate implementation of a varicella vaccination program less attractive. However, a lower price might make a freezer-stable vaccine more acceptable.

Although it is desirable to eliminate VZV in Canada, participants agreed that it is even more important to establish goals for implementation of vaccination programs as an intermediate step towards the reduction of VZV-associated morbidity and mortality. Given the diversity of vaccine program implementation in the provinces/territories, it was considered more feasible to establish realistic targets for disease reduction in 2005, by which time programs should be in place. It was felt that by the year 2005, the logistic difficulties with the currently licensed vaccine should have been overcome, irrespective of whether a refrigerator-stable vaccine is available in Canada. It was also emphasized that a goal of reducing hospitalizations will not be realized until all the major priority groups (by age and risk) identified at the conference have been vaccinated.

Criteria were developed for introducing routine varicella vaccination. Among other issues these took into consideration the technical feasibility of vaccine delivery (e.g. existence of an adequate freezer capacity) and the universal availability of the vaccine for all members of a target population. A number of the recommendations regarding varicella vaccination were targeted to susceptible persons in specified groups, defined as those persons without a history of varicella or vaccination. Once a routine childhood program is in place, the reasonable expectation is that coverage levels similar to current levels for measles vaccination can be reached; hence the coverage targets for varicella vaccination of susceptible children were linked to those for measles.

Several recommendations arising from the conference reinforced existing or ongoing public health initiatives and activities by other groups, such as the creation of a national immunization registry. The need to have a mechanism to prioritize vaccines within the broader discussion of public health funding was discussed extensively. Cost-sharing between the federal and provincial/territorial governments was proposed for further deliberation at the national level, for example, the possibility of federal funding of catch-up varicella immunization with provincial/territorial responsibility for the ongoing costs of varicella immunization.

Recommendation 1.1

The criteria for embarking on a routine varicella vaccination program should be as follows: Primary decisions:

• the vaccine is safe, effective and beneficial to the individual; and the burden of disease justifies program consideration.
• Absolute criterion: feasibility to deliver the vaccine to > 90% of the targeted population in each province/territory.
• Relative criteria: availability of a refrigerator-stable vaccine product; availability of a combination product; vaccine cost comparable to existing routine childhood vaccines; and 100% accessibility to a vaccination program.

With these absolute and relative criteria taken into consideration, all provinces/territories should have a routine childhood varicella immunization program by 2005.

Recommendation 1.2

Consideration having been given to the criteria for embarking on a routine varicella vaccination program, where the public health infrastructure can support childhood varicella vaccination this should proceed. Pending this, the following priorities for program implementation with the currently licensed freezer-stable varicella vaccine are suggested. Priorities must be reviewed with changes in vaccine formulation. Vaccination should be offered to susceptible persons in the following groups, in descending order of priority:

• health care workers and other special groups (as defined in the recommendations under Varicella Vaccine Use in Special Populations)
• selected immunocompromised groups (as defined in the recommendations under Special Populations), including those eligible for research protocols, and families and close contacts of these persons
• preteens at the time of other vaccination programs
• children at 1 year of age
• catch-up of children aged 1 year to preteens
• other adults

Recommendation 1.3

By 2005, a federal/provincial/territorial forum should establish reduction goals for VZV-associated morbidity.

Recommendation 1.4

By 2003, 100% of health care workers (as defined in the General Recommendation) should have known positive varicella serology, or a reliable history of disease, or documentation of varicella vaccination, or an acceptable medical contraindication to varicella vaccination.

Recommendation 1.5

By 2003, provincial and territorial immunization registries and a national immunization registry network should be developed, as per the ongoing registry initiative.

Recommendation 1.6

By the year 2010, varicella vaccination coverage targets should be tied to measles vaccination coverage targets to be achieved by the second birthday and by the seventh birthday¹.

Recommendation 1.7

The Advisory Committee on Population Health should propose to the Federal/Provincial/Territorial Deputy Ministers a formula for adequate federal funding of new immunization programs.

Recommendation 1.8

The Advisory Committee on Population Health should develop a mechanism to prioritize and introduce new vaccines with a view to harmonizing programs across the country.

1 The coverage targets voted on were 95% and 97% by the second and the seventh birthday respectively. However, the discussion was to link the varicella coverage targets to those for measles, which are 97% and 99% respectively⁽³⁾. The actual measles targets should be taken into consideration in program implementation and evaluation.

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