In addition, Cai et al. analyzed the methylation dataset of COVID-19 by utilizing the Monte Carlo feature selection method analyzed the methylation dataset of COVID-19 and found that EPSTI1, NACAP1, SHROOM3, C19ORF35 and MX1 as key features could significantly distinguish COVID-19 patients from non-COVID-19 patients [37, 38]. Here, PEAK3 is linked to COVID-19.