Abstract The persistence of serum-specific anti-chikungunya IgM antibodies (CHIKV-IgM) can vary after chikungunya fever (CHIK) infection. However, the factors related to its production are not yet known. We described a case series drawn up from data collected from 57 patients between 12 and 36 months after the acute phase of CHIK infection in Northeastern Brazil. CHIKV-IgM was detectable in 7/57 (12.3%) patient...