ABSTRACT
BACKGROUND: In countries like Australia where high coverage rates of early childhood vaccines has been achieved, ensuring timely vaccination is the next challenge--particularly where multiple doses are required for protection (e.g. DTPa vaccine). Since July 2007, for the first time, the Australian childhood vaccination schedule has included a vaccine (rotavirus vaccine) that must be administered within strict dosing windows. AIM: To determine whether the introduction of a 3-dose rotavirus vaccine (RotaTeq® into the national childhood immunisation program in Victoria, Australia, had an impact on the timeliness of the primary course of DTPa vaccine that is also scheduled at the same ages (2, 4 and 6 months). STUDY: We studied de-identified data of >17,000 children residing in four large and culturally diverse localities in the Eastern Region of Melbourne, Victoria who were born prior to or after the introduction of RotaTeq® into the National Immunisation Program schedule. Timeliness was defined as the proportion of children who received a particular dose of DTPa vaccine within the dosing window for the equivalent dose of RotaTeq®. We were particularly interested in any change in the timeliness of dose 3 of DTPa vaccine. RESULTS: Before the introduction of RotaTeq®, timely uptake of doses 1 and 2 of DTPa vaccine was high (93-97%). However, timeliness of the 3rd dose was markedly lower, dropping to 80% in one locality. In the post-RotaTeq® cohort, rates of timely uptake for doses 1 and 2 of DTPa vaccine remained high (97-99%). However, for DTPa vaccine dose 3, there was a clear trend toward improved timeliness--increasing by 5 to up to 12 percentage points compared with the pre-RotaTeq® cohort. CONCLUSION: Inclusion in the national immunisation schedule of the 3-dose vaccine RotaTeq® that has strict dosing windows encourages parents to present in a timely fashion for their child's vaccination, which in turn may drive an improvement in timeliness of other concurrently scheduled vaccines (e.g. DTPa). Introduction of government-funded RotaTeq® may improve the uptake of the crucial 3rd dose of DTPa vaccine, where traditionally the greatest delays are noted.
