Introduction Chikungunya viruses are endemic in tropical countries like Brazil. Healthcare workers (HCW) are at risk of infection in endemic areas. Besides causing chronic joint pain, the infection is hypothesised to be associated with mental health problems such as depression. However, no studies investigated this association and its relationship with sex are available.

Objectives To evaluate the association between previous infection by Chikungunya and depressive symptoms in HCW, investigating the role of sex in this relationship.

Methods This is a cross-sectional study with a representative sample (n = 343) of primary care and medium complexity HCW in the municipality of Santo Antônio de Jesus, Bahia, Brazil, in 2019. The DPP ZDC IgM/IgG rapid test was used to investigate recent infection (measured by IgM) or previous infection (by IgG) by the Chikungunya virus. The Patient Health Questionnaire (PHQ-9) was used to measure depressive symptoms. Poisson regression with robust variance estimation was used to estimate prevalence ratios (PR) and adjust for confounders. Stratified analyses by sex were performed.

Results The prevalence of recent or old Chikungunya infection was 8.9%, while the prevalence of depressive symptoms was 22.4%. Chikungunya infection was associated with a 2.05 (95%CI: 1.31–3.22) times higher prevalence of depressive symptoms in the bivariate analysis. After adjusting for sex, age, education, skin color and sequelae of chronic pain, the association remained strongly positive (PR = 1.74 (95%CI: 1.04–2.90)). Effect modification by sex was identified. The PR in men was 6.00 (95%CI: 1,98–18.16), while the in women was PR = 2.11 (95%CI: 1.29–3.44) in women.

Conclusions Findings reinforce the hypothesis that arboviruses, particularly Chikungunya, are independently associated with depression. Physiological viral action, as well as emotional, behavioural and psychosocial factors may partially justify these findings. Sex differences are notably high and must be further investigated, in order to understand possible mechanisms related to this association.