The impact of pneumococcal conjugate vaccine on rates of myringotomy with ventilation tube insertion in Australia.

Background: In randomized controlled trials and postmarketing studies the heptavalent pneumococcal conjugate vaccine (7vPCV) has been shown to reduce myringotomy with ventilation tube insertion (MVTI) procedures in a 4-dose schedule. In Australia, a 3-dose schedule at 2, 4, and 6 months of age is routinely used in non-Indigenous children. Our aim was to determine if a reduction in MVTI comparable to that documented in the United States occurred in Australia despite the absence of the booster dose. Methods: All episodes of MVTI in Australia from July 1998 to June 2007 among children aged ≤ 9 years were identified in an electronic database of national hospitalization records, including the public and private sectors. Age-stratified rates of MVTI before and after introduction of 7vPCV into the national immunization program in 2005 were determined, with Poisson regression modeling used to determine the vaccine impact after adjusting for background and seasonal trends. Results: A total of 238,634 hospital separations were identified. In the 2.5 years after routine 7vPCV introduction, there was a significant adjusted reduction in MVTI in children aged < 1, 1, and 2 years of 23%, 16%, and 6%, respectively. A nonsignificant reduction was observed in those aged 3 and 4 years, while a significant increase of 5% was observed for the 5- to 9-year age group. Conclusions: Although ecologic data such as this have limitations, the significant differential effects observed by time period and age group are suggestive of a vaccine effect of similar magnitude to that documented by postmarketing surveillance in the United States. The rapid uptake of 7vPCV in Australia, including catch up to 2 years of age, is an important difference to the United States and it is possible that an even greater effect would have been observed with a booster dose in the second year of life. Longer term data will be needed to fully assess the role of a booster dose.