Table 11 Pearson correlation coefficients (i) between the peak incidence and the average household size, as shown in Appendix Fig. 21 (effect of the average household size in 2016 and 2021), and (ii) between the peak incidence and the difference in average household size between 2016 and 2021, as shown in Appendix Fig. 22 (effects of the difference in average household size)