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Background We conducted a systematic review to assess whether measles humoral immunity wanes in previously infected or vaccinated populations in measles elimination settings. Methods After screening 16 822 citations, we identified 9 articles from populations exposed to wild-type measles and 16 articles from vaccinated populations that met our inclusion criteria. Results Using linear regression, we found that geometric mean titers (GMTs) decreased significantly in individuals who received 2 doses of measles-containing vaccine (MCV) by 121.8 mIU/mL (95% confidence interval [CI], −212.4 to −31.1) per year since vaccination over 1 to 5 years, 53.7 mIU/mL (95% CI, −95.3 to −12.2) 5 to 10 years, 33.2 mIU/mL (95% CI, −62.6 to −3.9), 10 to 15 years, and 24.1 mIU/mL (95% CI, −51.5 to 3.3) 15 to 20 years since vaccination. Decreases in GMT over time were not significant after 1 dose of MCV or after infection. Decreases in the proportion of seropositive individuals over time were not significant after 1 or 2 doses of MCV or after infection. Conclusions Measles antibody waning in vaccinated populations should be considered in planning for measles elimination.

Background Multiple survey reports suggest that alcohol use has increased in Canada during the COVID-19 pandemic. However, less is known about how per capita alcohol sales, which predict population-level alcohol use, have changed and whether changes in alcohol sales differ from changes in sales of other products due to pandemic factors. Methods We obtained monthly retail sales data by industry from Statistics Canada, for the six largest provinces in Canada (containing 93% of the national population), between January 2010 and November 2020, representing time before and 9 months after the start of the pandemic in Canada. We used an interrupted time series analysis to estimate pandemic impacts on the dollar value of monthly per capita (per individuals 15+ years) alcohol, essential and non-essential retail sales. We adjusted our analyses for pre-pandemic sales trends, inflation, seasonality and changing population demographics over time. Results During the first 9 months of the pandemic, the values of per capita alcohol, essential and non-essential sales were, respectively, 13.2% higher, 3.6% higher and 13.1% lower than the average values during the same period in the prior 3 years. Interrupted time series models showed significant level change for the value of monthly per capita alcohol sales (+$4.86, 95% CIs: 2.88, 6.83), essential sales (−$59.80, 95% CIs: − 78.47, − 41.03) and non-essential sales (−$308.70, 95% CIs: − $326.60, − 290.79) during the pandemic. Alcohol sales were consistently elevated during the pandemic, and the pre- and post-pandemic slopes were comparable. In contrast, essential and non-essential retail sales declined in the early months of the pandemic before returning to regular spending levels. Conclusion During the first 9 months of the pandemic, per capita alcohol sales were moderately elevated in Canada. In contrast, non-essential sales were lower than prior years, driven by large decreases during the initial months of the pandemic. These findings suggest that the pandemic was associated with increased population-level alcohol consumption, which may lead to increased alcohol-related harms. Ongoing research is needed to examine how factors, including pandemic-related stressors and specific alcohol sales-related policies, may have influenced changes in alcohol use and harms.

Background: Currently, sodium consumption of Canadians (2760 mg/day) exceeds the 2300 mg/day tolerable upper level putting Canadians at risk for hypertension and cardiovascular disease. Voluntary sodium reformulation strategies have been implemented in Canada, the United Kingdom (UK), United States (US) to reduce sodium intake from processed foods. The potential for sodium reformulation to reduce sodium intake across socioeconomic position (SEP) is not well understood. The objective of this study was to evaluate the extent to which fully achieving sodium reformulation targets for processed foods outlined in the Canada, UK, US strategies would decrease population and social inequities in sodium intake in Canadian adults. Design: A cross-sectional study was conducted using the 2015 Canadian Community Health Survey–Nutrition (n=13,519 participants aged ≥19 years, 53% females). Foods from the 24-hour dietary recall were matched to each country’s sodium reduction categories and target sodium levels were applied. Multivariable linear regressions were used to estimate mean sodium intake for the population and across SEP indicators (educational attainment, household food security, and household income adequacy quintiles). Results: Achieving Canada’s targets would reduce average sodium intake by 228 mg/day (95%CI: 196,260) compared to baseline. UK’s sodium targets would achieve greater reductions, decreasing average sodium intake by 270 mg/day (95%CI: 242,299). The US sodium targets would increase average sodium intake by 98 mg/day (95%CI: 64,132). Achieving sodium reformulation targets resulted in greater reductions in sodium intake in men, and in lower SEP groups. For example, educational inequalities in sodium intake observed at baseline were reduced in men [Canada: (RD: 148 mg/day, 95%CI: -30,327); UK: (RD: 152 mg/day, 95%CI: -43,347)] and eliminated in women. Conclusion: Achieving targets outlined in Canada and UK’s voluntary sodium reformulation strategies would significantly reduce mean sodium intake in Canadians. This study demonstrated the potential for reducing social inequities in sodium intake and health.

Objective To build an open source spatiotemporal system that integrates analysis and visualization for disease surveillance Introduction Most surveillance methods in the literature focus on temporal aberration detections with data aggregated to certain geographical boundaries. SaTScan has been widely used for spatiotemporal aberration detection due to its user friendly software interface. However, the software is limited to spatial scan statistics and suffers from location imprecision and heterogeneity of population. R Surveillance has a collection of spatiotemporal methods that focus more on research instead of surveillance Methods Based in Ontario, Canada, we used postal codes for determining the location of cases of reportable infectious diseases. The variation in geographic sizes and shapes of the case and census geographies created challenges for developing a uniform temporal spatial surveillance system, including: Linking case and population data due to misclassification errors, Distance based correlations due to irregularly shaped areas (e.g. FSA’s), and Visualization bias due to variation in population density, e.g. large area with little population. To overcome these challenges, we developed the Ontario Hybrid Information Map (OHIM) boundary, which is a combination of Public Health Unit boundaries (rural areas), census subdivisions (rural urban mixed) and regular grid cells (urban). The goal is to capture population details in urban areas without losing information in rural areas. OHIM has around 4600 geographies with more than half located in urban centers. Population distribution by gender and age group was calculated for each OHIM geography. A lookup file was also created to link all Ontario postal codes to OHIM geography. To create baselines, historical data for influenza A were used to model the seasonality and calculate expected case count for each OHIM geography for each week. Standardized incident ratios (SIR) were calculated as exploratory statistics, and a spatiotemporal Besag- York-Mollie (BYM) model was used to calculate the probability that the risk is higher than a pre-specified threshold. Integrated Nested Laplace Approximation (R-INLA) was used in R to explore different types of spatiotemporal interactions and for fast Bayesian inference. The ability to apply the models was verified by examining previous outbreaks and seeking the opinion of staff that routinely perform surveillance on influenza. To ensure the visualization integrates with the analysis, R package Shiny was used to build an interactive spatiotemporal visualization on OHIM boundary utilizing Open Street Map and html5. The application not only allows users to pan and zoom in space and time to explore the results and locate high risk areas, it also gives users the flexibility to change algorithm parameters for instant feedback. Figure 1 demonstrates a zoomed-in OHIM boundary with pointers signal for “high risk” area at user specified statistics exceeds a threshold (e.g., SIR > 2). Using the algorithms and visualization tools, surveillance experts pick the optimal time and place to be notified based on historical data and therefore the optimal threshold, which will be verified by prospectively running the algorithms. Results The OHIM boundaries build the foundation for efficient spatial modelling and visualization for public health surveillance in Ontario. Together with the integrated modelling and visualization system, staff are able to interactively optimize the aberration thresholds and identify potential outbreaks in real time. Staff reported preference of SIR due to its faster computations and easier interpretation. One major challenge was scalability: the ability to handle high resolutions of spatiotemporal data. When the system was applied on 4600 polygons by 200 weeks, significant delays were encountered in both analysis and visualization. Difficulties in computational time, memory requirement and visualization interactivity created delays and freezing, thereby limited user experience. This problem was partially addressed by optimizing parameters for fast computations Conclusions This work shows the “proof of concept” for an open source, customizable spatiotemporal surveillance system that overcomes existing data challenges in Ontario. However, more work is required to make this fully operational and efficient in production.

Objective To describe the spatial distribution of incident cases of systemic lupus erythematosus (SLE) using geographic information systems (GIS). Methods Spatial analyses were carried out on 890 SLE patients and 541 psoriatic arthritis (PsA) patients (controls). Age- and sex-adjusted rates for SLE/PsA for each census tract were calculated using denominator population values from the Canadian census. Spatial variations in relative risk were estimated by modeling risk as the product of a time effect, an age effect, and a spatially autocorrelated risk surface to identify hot spots. Patients within the detected hot spot were compared to those outside the hot spot to identify explanatory factors. Results SLE patients were predominantly female (87.75%) and the incidence rate was highest among those 15–19 years of age (2.4 cases/100,000 person-years). In an SLE hot spot containing 59 patients, 100% of the patients were female and 49.1% (n = 29) were Caucasian, while outside of the hot spot, 86.9% (n = 722) of the patients were female and 68.4% (n = 568) were Caucasian. The proportion of cases of Chinese ethnicity was significantly greater within the hot spot. An interaction was found between Chinese ethnicity and residence within the hot spot, with the risk of SLE to the Chinese population found to be twice the risk to the non-Chinese population. Conclusion GIS was used to map SLE cases and a hot spot was identified after adjustment for age and sex. Ethnicity by itself did not confer an increased risk of SLE, but the interaction of ethnicity with location of residence significantly increased the risk of SLE.

We examined malaria cases reported to Ontario’s public health surveillance systems from 1990 through 2009 to determine how temporal scale (longitudinal, seasonal), spatial scale (provincial, health unit), and demography (gender, age) contribute to Plasmodium infection in Ontario travellers. Our retrospective study included 4,551 confirmed cases of imported malaria reported throughout Ontario, with additional analysis at the local health unit level (i.e., Ottawa, Peel, and Toronto). During the 20-year period, Plasmodium vivax accounted for 50.6% of all cases, P. falciparum (38.6%), Plasmodium sp. (6.0%), P. ovale (3.1%), and P. malariae (1.8%). During the first ten years of the study (1990–1999), P. vivax (64% of all cases) was the dominant agent, followed by P. falciparum (28%); however, during the second ten years (2000–2009) the situation reversed and P. falciparum (55%) dominated, followed by P. vivax (30%). The prevalence of P. falciparum and P. vivax cases varied spatially (e.g., P. falciparum more prevalent in Toronto, P. vivax more prevalent in Peel), temporally (e.g. P. falciparum incidence increased during the 20-year study), and demographically (e.g. preponderance of male cases). Infection rates per 100,000 international travellers were estimated: rates of infection were 2× higher in males compared to females; rates associated with travel to Africa were 37× higher compared to travel to Asia and 126× higher compared to travel to the Americas; rates of infection were 2.3–3.5× higher in June and July compared to October through March; and rates of infection were highest in those 65–69 years old. Where exposure country was reported, 71% of P. falciparum cases reported exposure in Ghana or Nigeria and 63% of P. vivax cases reported exposure in India. Our study provides insights toward improving pre-travel programs for Ontarians visiting malaria-endemic regions and underscores the changing epidemiology of imported malaria in the province.

To describe the spatial distribution of incident cases of systemic lupus erythematosus (SLE) using geographic information systems (GIS).Spatial analyses were carried out on 890 SLE patients and 541 psoriatic arthritis (PsA) patients (controls). Age- and sex-adjusted rates for SLE/PsA for each census tract were calculated using denominator population values from the Canadian census. Spatial variations in relative risk were estimated by modeling risk as the product of a time effect, an age effect, and a spatially autocorrelated risk surface to identify hot spots. Patients within the detected hot spot were compared to those outside the hot spot to identify explanatory factors.SLE patients were predominantly female (87.75%) and the incidence rate was highest among those 15-19 years of age (2.4 cases/100,000 person-years). In an SLE hot spot containing 59 patients, 100% of the patients were female and 49.1% (n = 29) were Caucasian, while outside of the hot spot, 86.9% (n = 722) of the patients were female and 68.4% (n = 568) were Caucasian. The proportion of cases of Chinese ethnicity was significantly greater within the hot spot. An interaction was found between Chinese ethnicity and residence within the hot spot, with the risk of SLE to the Chinese population found to be twice the risk to the non-Chinese population.GIS was used to map SLE cases and a hot spot was identified after adjustment for age and sex. Ethnicity by itself did not confer an increased risk of SLE, but the interaction of ethnicity with location of residence significantly increased the risk of SLE.