Medical practices such as repositioning and respiratory tract suction increased the infection risk, but our study revealed that the genetic variants in the TMPRSS2 gene contributed to increased susceptibility to SARS-CoV-2 infection, although the statistical power was not optimal due to the limited number of participants (the dominant model; 0.5349 for the close contact noninfected group vs. the moderate group and 0.6714 for the asymptomatic-to-mild group vs. the moderate group). Here, TMPRSS2 is linked to infection.