Figure 3.

Incidence of acute COVID-19 symptoms according to age

The incidence of acute COVID-19 symptoms in patients with COVID-19 aged 0-19, 20-59, and 60-85 years in all three observation periods. The p-value between the two groups was calculated using the chi-squared or Fisher’s exact tests and then compared with a corrected significance level using Bonferroni’s method (α′). Asterisks indicate that the p-value was less than α′ using different original significance level (α); **** α = 0.0001, *** α = 0.001, ** α = 0.01, and * α = 0.05. ns indicates no significant difference.