Impact of a Publicly Funded Herpes Zoster Immunization Program on the Burden of Disease in Ontario, Canada: A Population-based Study

Abstract

Background In September 2009, a live attenuated herpes zoster vaccine (ZVL) became available in Canada. Beginning in September 2016, ZVL was made available to all Ontario residents aged 65–70 through a publicly funded immunization program. We assessed the impact of ZVL availability and its subsequent public funding on herpes zoster burden in this population. Methods A population-based study of Ontario residents aged 65–70 between January 2005 and September 2018. We used interventional autoregressive integrated moving average models to examine the impact of ZVL market availability and the publicly funded ZVL program on monthly incidence rate of medically attended herpes zoster, defined as an outpatient visit for herpes zoster with a prescription for a herpes zoster antiviral dispensed ≤5 days before or after the visit, or a herpes zoster–related emergency department (ED) visit or hospitalization. In secondary analyses, we examined impacts on any herpes zoster–related ED visits and hospitalizations. Results We found no association between ZVL market availability and monthly incidence of herpes zoster (P = .32) or monthly rates of ED visits and hospitalizations (P = .88). Conversely, the introduction of publicly funded ZVL reduced the monthly rate of medically attended herpes zoster by 19.1% (from 4.8 to 3.8 per 10 000 population; P < .01) and herpes zoster–related ED visits and hospitalizations by 38.2% (from 1.7 to 1.0 per 10 000 population; P < .05). Conclusions The introduction of a publicly funded immunization program for herpes zoster was associated with reduced disease burden and related acute healthcare service use.

Impact of changes in opioid funding and clinical policies on rapid tapering of opioids in Ontario, Canada

“…In our monthly analysis, we fit interventional autoregressive integrated moving average (ARIMA) models to the data to test for significant changes in the prevalence of rapid tapering events when 4 distinct policies and guidelines were introduced, a method commonly used for population-based time-series analyses. 23 , 28 The ARIMA model requires 3 parameters: the p parameter (autoregressive term for the number of previous data points to account for), d parameter (number of model differences to achieve stationarity in the time series), and q parameter (order of moving average). To fit the ARIMA model, we first differenced the time series (ARIMA model d parameter equal to one) to achieve stationarity, which was confirmed visually and through the augmented Dickey–Fuller stationarity test.…”

Impact of a National Immunisation Program on herpes zoster incidence in Australia

“…13, 23 This sex difference was also observed in the Canadian study. 21 The fall in incidence post-program was also observed to be relatively uniform across Australian regions (by remoteness) and socioeconomic groups, and also in most jurisdictions, although not in the Northern Territory and Western Australia. The lack of a reduction in incidence in the Northern Territory may be due to the small number of participating practices in our sample and therefore a lack of power to detect a difference; although vaccine coverage in the Northern Territory is also reported to be substantially lower 23 .…”

“…In the Canadian province of Ontario, a zoster immunisation program was introduced in September 2016 for adults aged 65-70 years. 21 Results of a national survey showed vaccine uptake was 21% among participants aged ≥50 years in 2016 22 and the monthly incidence of medically-attended zoster in the 2 years after program implementation was reported to decrease by 1 per 10,000 population 21 .…”

Global herpes zoster incidence, burden of disease, and vaccine availability: a narrative review

“…In 2008, ZVL was approved for use in Canada as part of a universal immunization program for individuals over the age of 50. 72 With the authorization of the RZV vaccine in October 2017, the Canadian government commissioned the National Advisory Committee on Immunization (NACI) to conduct a head-to-head comparison of ZVL to RZV. 42 , 73 The 2018 report found that overall, both vaccines were more cost-effective than no vaccination, but RZV was the preferred vaccine given greater cost-effectiveness and efficacy at all age groups.…”