Prophylactic effect of cutaneous leishmaniasis against COVID-19: a case-control field assessment

ABSTRACT: Introduction: We assessed the potential relationship between COVID-19 and laboratory-confirmed cutaneous leishmaniasis (CL)-registered cases with a history of scarring, compared with volunteer participants without history of CL. Methods: This case-control retrospective study was conducted in southeastern Iran with a high anthroponotic cutaneous leishmaniasis (ACL) burden. Results: Overall, n=1010 CL cases (n=479 male, n=531 female) were evaluated for infection with SARS-CoV-2. In the CL case group, 2 men and 1 woman (0.3% in total) had a mild form of COVID-19 disease; none were hospitalized or died. In contrast, of n=2020 participants without history of CL, n=57 (2.9%) contracted laboratory-confirmed COVID-19, including mild (66.7%), hospitalized (26.3%), critical (3.5%) and fatal (3.5%). There was a strong negative association between CL infection and COVID-19. The burden of COVID-19 in CL-cured participants significantly reduced the morbidity (odds ratio: 0.12; CI: 0.03–0.30; P