Varicella vaccination for grades 4 and 5 students: from theory to practice.

BACKGROUND In 2002-2003, as part of a pilot project, varicella vaccination was offered to susceptible students in grades 4 and 5 in schools whose health services are provided by a local community services centre in Montréal. This immunization campaign was merged with the hepatitis B immunization programme. OBJECTIVES To calculate the proportion of grade 4 and 5 students susceptible to varicella; to calculate the proportion of susceptible students who agree to be vaccinated; to compare the proportion of susceptibles who agree to be vaccinated when varicella vaccination is offered with the first or the second dose of hepatitis B; and to assess whether a catch-up varicella immunization programme would affect the vaccine coverage of a concurrent hepatitis B vaccination programme. METHODS The proportions of susceptible students and of parents of susceptibles who consented to vaccination were calculated. The proportions of parents of susceptibles who consented to vaccination were compared for both immunization strategies: varicella vaccination given with the first or second dose of hepatitis B vaccine. Logistic regression was performed to identify possible associations between consent to varicella vaccination and the various variables collected. Rates of vaccine coverage against hepatitis B after two doses were compared for the years 2000-2001 and 2002-2003. RESULTS Of 3,856 registered students, 3,486 (90.4%) returned consent forms. Among the 3,272 students for whom information was available, 441 (13.5%) were susceptible, including 394 (89.3%) who consented to vaccination. The rates of vaccine coverage in the schools after two doses of hepatitis B vaccine were exactly the same for the 2000-2001 and 2002-2003 school years. CONCLUSION Varicella vaccination of susceptible grade 4 and 5 students associated with a coincident hepatitis B vaccination campaign can be performed without negative impact on the hepatitis B vaccination programme.