Statistical analysis
Initially, descriptive and exploratory analyses of all data were performed. Data were summarized as frequencies and percentages for categorical variables and as means and standard deviations or medians and interquartile ranges for continuous variables. Then, the three groups were compared using Fisher’s exact test for categorical variables and generalized linear models for continuous variables (age and onset of symptoms). The Ct values met the assumptions for parametric analysis and were analyzed using generalized linear models for repeated measures. They were also analyzed for variations in the Ct value in relation to the baseline by one-way analysis of variance and Tukey’s test. Finally, associations between groups and a classification of infectivity (high, intermediate, and low) were analyzed based on Ct values using Fisher’s exact test. All analyses were performed using the R Core Team program (R Foundation for Statistical Computing, Vienna, Austria) with a significance level of 5%. All tests were based on the null hypothesis of the three interventions having an equivalent effect on the Ct value.