Canada Communicable Disease Report

Final Report of Outcomes from the National Consensus Conference for Vaccine-Preventable Diseases in Canada

June 2005

Disease Summaries

This section is a summary of workshop and plenary session outcomes for each of the six diseases, as well as the highlights of participant feedback from the consensus conference.

Discussion guides used to support working group deliberations can be found in Appendix B. Reference articles and conference documents are available on CD-Rom by sending a request to: programs.irid-diir@phac-aspc.gc.ca.

Rubella

Background

The purpose of this session was to review recent evidence and determine the feasibility of adopting the WHO/PAHO (World Health Organization/Pan-American Health Organization) goal of rubella elimination by 2010. To support discussion, presentations were given on rubella incidence and elimination in the US, the Americas and Canada.

United States:

(Dr. Jane Seward, CDC)

In November 2004, the US announced the achievement of its goal of eliminating rubella and congenital rubella syndrome (CRS), well ahead of 2010. Reported rubella and CRS cases have declined significantly since immunization coverage was extended to adults, including foreign-born adults, people in workplaces and women of childbearing age. There is extremely high coverage with the recommended one dose of a rubella-containing vaccine and many children receive two MMR (measles, mumps and rubella) doses due to school requirements for measles immunization. In the US, there are record low levels of reported rubella with < 1 case per million people and only isolated and import-related cases identified. Surveillance has shown population immunity among persons 6 to 49 years of age to be very high, at over 91%. After reviewing these and other data, an expert panel, convened in October 2004, concluded that the US had achieved rubella elimination or absence of endemic rubella transmission.

The Americas:

(Dr. Carlos Castillo-Solórzano, PAHO)

PAHO is currently pursuing its 2003 goal to interrupt endemic rubella virus transmission in the Americas and eliminate CRS cases associated with endemic transmission by 2010. The PAHO strategy incorporates integrated surveillance systems, rubella virus isolation, routine childhood immunization programs, and follow-up and public awareness campaigns for children and adults using the MMR vaccine. Challenges include strengthening surveillance and reporting, developing a regional database, accelerating implementation of immunization strategies, improving follow-up with female rubella outbreak victims, and collecting specimens.

Canada:

(Dr. Gaston De Serres)

In 1994, a goal to eliminate rubella and CRS by the year 2000 in Canada was recommended. Immunization targets included one-dose immunization coverage of 97% for children by their second birthday and two-dose coverage at school-entry age, as well as immunization for 14 to 15 year-olds who may have been missed. Targets were also established for pregnant women, with all susceptible women to receive postpartum immunization prior to hospital discharge. Immunization is currently required for all children and recommended for women of childbearing age and people from countries with no rubella immunization program.

The incidence of rubella in Canada has decreased steadily since the implementation in 1996 of a two-dose MMR vaccine for measles, mumps and rubella. Still, as demonstrated by an outbreak in Manitoba in 1997, an outbreak in Ontario in 2005, and a handful of isolated cases, limited rubella virus transmission will continue due to importation, secondary spread, gaps in immunization coverage (e.g., men or populations declining to participate in immunization programs).

Ontario:

(Dr. Barbara Kawa)

A large rubella outbreak (305 cases) occurred in the summer of 2005 in a close-knit religious community in south western Ontario. Ontario legislation requires that school pupils be immunized against rubella (or present a valid medical exemption or exemption due to religious/philosophical belief). While the overall coverage rate in Oxford County is comparable to the provincial rate of 95%, the affected community has a high proportion of unvaccinated persons, due to religious reasons. Despite outbreak control activities, including ongoing monitoring and immunization of susceptible populations, communities with low coverage continue to be a concern.

Discussion

The following issues related to the development of national goals for rubella control were identified during the plenary session. The discussion guide used by participants is attached in Appendix B.

School entry targets: It was recommended that the age of "school entry" be changed to "by the 7^th birthday" for coverage measurement purposes. Further, it was suggested that regions with legislated school-entry requirements be identified and studied in comparison with other regions to assess the impact of legislation on immunization coverage.

Adolescent targets: The merit in setting a rubella immunization target for children aged 15 to 17 was questioned, given that there is no system in place to monitor coverage of this age group. In response, it was noted that this age group is currently targeted for the Tdap booster; presenting a final opportunity to administer rubella-containing vaccine.

Unvaccinated populations: Experiences with rubella outbreaks in unvaccinated populations were shared, including possible response strategies. Acknowledgement was made of the challenge posed by populations refusing immunization and the importance of developing a prevention culture in which immunization is promoted and accepted. Ideally, governments could "decree immunization as a national priority without resorting to legal measures". However, this may prove difficult; as evidenced in the US, where pressure is growing to disallow religious and philosophical exemptions.

Setting goals and recommendations

Taking into account the evidence presented, participants agreed upon the following consensus statements for national goals and recommendations for implementation to eliminate indigenous rubella transmission in Canada.

Goal

Adopt the WHO/PAHO regional goal to eliminate indigenously transmitted cases of rubella and CRS from Canada by 2010.

Disease incidence

Recommendation 1

Decrease the rate of rubella-negative primigravida women to < 4% by 2010, by ensuring that all women of childbearing age have a documented history of rubella immunization and, if not, that they are offered a rubella-containing vaccine.

Rationale: The target date was changed from 1997 to 2010 to conform with the WHO/PAHO goal.

Immunization coverage

Recommendation 2

Achieve and maintain age-appropriate immunization coverage for rubella-containing vaccine in 97% of children by their 2^nd birthday (1 dose) by 2010.

Rationale: The coverage target was reduced from 99% to 97% in recognition of the continued possibility of imported cases and the challenge of controlling rubella outbreaks in under-immunized pockets of the general population.

Recommendation 3

Achieve and maintain age-appropriate immunization coverage with rubella-containing vaccine in 97% of children by their 7^th birthday (2 doses) by 2010.

Rationale: The age milestone was changed from "school entry" to "by the 7^th birthday" to conform with current coverage standards for age milestones.

Recommendation 4

Achieve and maintain age-appropriate immunization coverage with rubella-containing vaccine among 97% of adolescents 14 to 16 years of age by 2010.

Rationale: The upper boundary of the age range was increased to 16 years to provide increased opportunity to immunize susceptible teens by taking advantage of the health encounter for Adacel^® (acellular pertussis [Tdap]) booster.

Recommendation 5

Achieve and maintain rubella postpartum immunization coverage in 99% of susceptible women prior to hospital discharge by 2010.

Rationale: The target date was changed from 1997 to 2010 to conform with the WHO/PAHO goal.

Other

Recommendation 6

Screen serology and/or obtain date of immunization of ALL pregnant women seen pre-natally for rubella susceptibility by 2010.

Rationale: The target date was changed from 1997 to 2010 to conform with the WHO/PAHO goal.

Vote

Participants achieved consensus on all goals and recommendations for rubella elimination. In conclusion, it was also recommended that a national action plan for eliminating rubella should be developed collaboratively and endorsed by all levels of government in the coming year.