In a prospective study [41] on 31 subjects with long-term COVID-19 (diagnosis based on finding of at least one of three main symptoms: dyspnea, fatigue and chest pain) and a control group of asymptomatic subjects with only a history of illness, an 8-month comparative analysis showed that patients with long COVID-19 had persistent increases in activated lymphocytes CD14+, CD16+, monocytes, plasmacytoid, dendritic cells and type I (IFNβ) and type III (IFNλ1) interferon levels [41]. Here, IFNL1 is linked to COVID-19.