Investigating the Relationships Between COVID-19 Cases, Public Health Interventions, Vaccine Coverage, and Mean Temperature in Ontario and Toronto

<b>Background/Objectives:</b> We aimed to examine the relationship between COVID-19 cases and Public Health Interventions (PHIs), vaccine coverage, and temperature. We compared our findings with those of other studies that used different methodologies, such as mathematical models. <b>Methods</b>: We developed monthly PHI scores using the Oxford COVID-19 Government Response Tracker from May 2020 to May 2021. We calculated PHI scores by summing the highest monthly score of each intervention and expressed the PHI score as a percentage of the maximum. We obtained vaccine coverage and temperature data from January 2021 to September 2023. We calculated Spearman's rank-order correlation coefficients to examine correlations. <b>Results</b>: The correlation between cases and PHI was positive (ρ = 0.947, <i>p</i> < 0.0001). The correlation between cases and vaccine coverage was approximately zero (ρ = 0.0165, <i>p</i> = 0.957) from January 2021 to January 2022 and was negative from February 2022 to September 2023 (ρ= -0.816, <i>p</i> < 0.0001). The correlation for cases and temperature was negative from January 2021 to January 2022 (ρ = -0.676, <i>p</i> = 0.0112) and was almost zero from February 2022 to September 2023 (ρ = -0.162, <i>p</i> = 0.494). The models showed a negative correlation between PHI and vaccine coverage, and mixed results for temperature. <b>Conclusions</b>: There was a positive correlation between cases and PHI. Prior to reaching the vaccine threshold coverage, there was no correlation for vaccination and a negative correlation for temperature. Post-vaccine threshold, there was a negative correlation for vaccination and no correlation for temperature. Correlation results for PHI and temperature differed from those of the mathematical models.