Effectiveness of monovalent rotavirus vaccine in a high-income, predominant-use setting
Introduction
Rotavirus was the major cause of pediatric gastroenteritis among Canadian children during the pre-vaccine era [1], [2], [3], [4], [5], [6], [7]. Before vaccination, up to 1 in 40 Canadian children <5 years of age required hospitalization or emergency care annually for rotavirus gastroenteritis [7]. Two oral rotavirus childhood vaccines are licensed in Canada [8], [9]: Rotarix® (RV1; trademark of the GlaxoSmithKline group of companies), a monovalent vaccine containing strain G1P[8], administered as a 2-dose series, and RotaTeq® (RV5; trademark of Merck & Co., Inc.), a pentavalent vaccine containing strains G1–G4 and P1A[8], administered as a 3-dose series. As of September 2014, 9 Canadian provinces and territories adopted public reimbursement for RV1-only under provincial insurance plans; the remaining 4 provinces and territories do not reimburse for either vaccine [10].
Given differences in formulations and dosing, comparison of the direct effect, or vaccine effectiveness (VE), of RV1 and RV5 is of considerable interest [11], [12], [13], [14], [15], [16], [17], [18]. Results from post-licensure evaluations in high-income jurisdictions with concurrent RV1 and RV5 use reveal high, indistinguishable effectiveness of each vaccine of >70% to prevent rotavirus hospitalizations and emergency visits [11], [12], [13], [14], [15], [17]. RV5 VE was similar in several high-income locales with exclusive RV5 use – either prior to RV1 licensure/uptake, or in a jurisdiction with its exclusive reimbursement [19], [20], [21], [22], [23], [24], [25]. Since effects of concurrent RV1 and RV5 use may differ from exclusive RV1 use, it is important to evaluate RV1 VE in settings without concurrent RV5 vaccination. However, to our knowledge, RV1 effectiveness in a high-income, non-outbreak setting where RV1 is predominantly used has only been assessed in Belgium [26].
We conducted a test-negative case control study to assess RV1 VE to prevent rotavirus emergency visits and hospitalizations among young children in a Canadian setting with predominant RV1 use, and examined the effect of increasing vaccination coverage on the prevalence of pediatric rotavirus over time.
Section snippets
Study setting
In November 2011, Quebec implemented a publicly funded RV1 vaccination program with its routine administration at 2 and 4 months of age. From February 1, 2012–May 31, 2014, we conducted prospective, active surveillance for acute rotavirus gastroenteritis at The Montreal Children's Hospital and Centre Hospitalier Universitaire Sainte-Justine, located in Montreal, and Centre Hospitalier Universitaire de Sherbrooke, located in Sherbrooke. Active surveillance was approved by Research Ethics Boards
Study population
From February 1, 2012–May 31, 2014, we enrolled 866 of 4,849 (17.9%) eligible patients with acute gastroenteritis in active surveillance (Fig. 1A). Of these, 728 (84.1%) participants were included in active surveillance analyses; 144 (19.8%) were rotavirus-positive. Rotavirus ≥1-dose coverage was 46.4% (95% CI: 42.8%, 50.1%); among those vaccinated, 91.4% (95% CI: 87.9%, 93.9%) received RV1 only (i.e. not RV5).
Among active surveillance participants, 384 (52.7%) were age-eligible to receive 2
Discussion
We examined the effect of increasing rotavirus vaccine coverage on rotavirus prevalence and assessed RV1 VE in a setting with predominant RV1 use. With 2.5 years of post-implementation data, increasing rotavirus vaccine coverage was associated with a decrease in rotavirus prevalence over time, and on average, a 1% increase in 2-dose RV1 coverage among children 1 year of age was associated with a nearly 4% relative decrease in rotavirus prevalence among children <3 years of age. RV1 was highly
Conclusion
With data from 3 seasons following the implementation of an exclusive-RV1 vaccination program, we observed significant declines in the prevalence of rotavirus-associated pediatric gastroenteritis, and estimate that RV1 was >90% effective in preventing emergency visits and hospitalizations among children <3 years of age. RV1 VE did not differ from estimates from comparable jurisdictions with concurrent RV1 and RV5 use. While we observed an increase in heterotypic and partly-heterotypic rotavirus
Funding
Arnaud Gagneur has previously received funding from GlaxoSmithKline (speaker, honoraria), Merck (research grant or support, speaker/honoraria), Sanofi-Pasteur MSD (research grant or support, speaker/honoraria), & Wyeth (research grant or support, speaker/honoraria. Bruce Tapiero has received research grant or support from Novartis and Sanofi-Pasteur. Caroline Quach has received funding from GlaxoSmithKline, Pfizer, Sage and AbbVie (all for research grant or support). The remaining authors have
Acknowledgements
This study was supported by a research grant from GlaxoSmithKline Biologicals SA (GSK). We would like to thank Milagros Gonzales for her help in management of the project and data, Thomas Lemaître, Suzanne DeRome, and Léna Coïc for their help in recruiting patients on various sites, as well as the MUHC Vaccine Study Centre personnel.
Conflict of interest: The authors have no conflicts of interest to disclose. GSK did not participate in any of the protocol writing, planning, implementation,
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