[Table of Contents]

Volume: 25S5 - August 1999

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

Development and Implementation of Varicella Vaccination Programs

Strategies for vaccine delivery in a routine immunization program were discussed on the basis of separate assumptions that (1) the only vaccine available would be the currently licensed freezer-stable product, or (2) a refrigerator-stable vaccine would be available. Recommendations regarding program implementation were proposed that took into account the desire to achieve high coverage rates as quickly as possible. However, participants acknowledged that specific strategies and decisions regarding actual program implementation would have to be made by provincial/territorial authorities.

Concerns about the capacity to deliver a freezer-stable vaccine effectively pertain to Health Canada's Medical Services Branch and other jurisdictions responsible for vaccination programs, as well as to provincial/territorial public health departments. Participants were hesitant to recommend costly cold chain improvements that might quickly become redundant if a refrigerator-stable product soon became available in Canada. Furthermore, introduction of a full freezer cold chain for varicella vaccine could adversely affect other immunization programs as a result of the costs. Direct distribution by the manufacturer to clinics was discouraged because of inherent drawbacks: the difficulty of inducing clinics to provide records to provincial/territorial public health departments; the lack of provincial/territorial public health control of administrative aspects of program delivery, including funding and cold chain maintenance; and the ethical issues associated with providing lists of vaccinators in any jurisdiction to a specific manufacturing company. It was also noted that for the purpose of public purchase, it would be useful to obtain the actual cost of the vaccine (i.e., after the transportation and storage costs factored into the current price have been subtracted).

Participants reiterated that universal vaccination of young children with the freezer-stable vaccine is not feasible at this time, but that in the meanwhile an interim strategy should be adopted to make the vaccine accessible to preteens and to selected risk groups as defined in the recommendations under Special Populations. The importance of using a phased approach, to allow time for consideration of a variety of outstanding issues, was stressed. The best option for universal vaccination of young children is to implement a program within 2 years of the introduction of a refrigerator-stable vaccine, to be followed by a 5-year catch-up program for susceptible preteens. Options to be considered for a catch-up program include mass vaccination (ideal but costly), immunization of preteens linked with school-based hepatitis B vaccination, vaccination at school entry, or a combination of these. No specific age limits were defined for catch-up programs in order to provide flexibility in provincial/territorial implementation strategies, which will differ according to existing public health systems. However, implementation of catch-up programs should allow for coverage of all age cohorts up to the age targeted for pre-adolescent immunization.

Recommendation 2.1

A universal immunization program for young children should be implemented within 2 years of the availability of a refrigerator-stable vaccine.

Recommendation 2.2

Systematic immunization should begin as soon as possible for susceptible preteens < 13 years of age with whatever vaccine is available, preferably through a school-based program. Immunization of prioritized at-risk persons, as defined in the recommendations under Special Populations, should be initiated at the same time.

Recommendation 2.3

As soon as a universal program is in place, a catch-up program for susceptible persons < 13 years of age should be initiated and completed within 5 years.

Recommendation 2.4

Primary immunization of children < 13 years of age should be done with one dose. Surveillance must be planned in order to permit reassessment of this policy.

Recommendation 2.5

There should be no booster dose planned in the vaccination program. Research is required to measure the need for booster vaccination to prevent varicella and herpes zoster, and for timing of boosters if needed.

Recommendation 2.6

Vaccine should be administered to children as early as recommended (by the manufacturer) for a given vaccine. When possible, it should be linked with a vaccination visit already in place.

Recommendation 2.7

Before the use of a freezer-stable vaccine is contemplated, the following critical conditions must be met: appropriate freezers must be in place to maintain vaccine at minus 15^o C; there should be an appropriate monitoring system for maintenance of the cold chain; an appropriate system of vaccine delivery to maintain vaccine at minus 15^o C must be in place; all vaccine handlers must be trained on proper vaccine storage and handling requirements; there should be a system in place to monitor vaccine wastage; and availability of dry ice must be ensured.

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