In the PCS group, we did not include patients who had severe COVID-19 and reported fatigue for at least 12 weeks after initial diagnosis (mean, 314 days; median, 252 days), as it is known that anti-IFN autoantibodies are relatively prevalent in patients critically ill with COVID-19 (at least 10%) [2, 3]. Here, IFNA1 is linked to COVID-19.