Factors mediating and associated with immunological response in women living with HIV in Sweden: A nationwide register-based study.

Introduction: Women remain underrepresented in studies on immunological response (IR) among virally suppressed people living with HIV. Despite receiving antiretroviral therapy (ART) some individuals do not attain an IR, increasing their risk of non-AIDS morbidity and mortality. This nationwide study investigated biomedical and social factors associated with IR among women with HIV in Sweden.

Methods: We conducted a register-based cohort study using the Swedish National HIV Registry (InfCareHIV). Virally suppressed women diagnosed with HIV between 2000 and 2020, ≥18 years old were included. Included women were observed for 2 years after ART initiation. The associations between IR and clinical and social determinants were investigated using logistic regression.

Results: There were 841 women included in the final model, of whom 90% (n = 739, 95% CI: 0.88-0.92) had an IR after a 2-year follow-up. Mean age was 37 years at inclusion, and 52% (n = 439) were born in a sub-Saharan African country. A significant interaction between baseline HIV viral load and HIV acquisition mode was observed. Higher baseline HIV viral load (≥100 000 copies/mL) increased the odds of IR (adjOR 1.81, 95% CI: 0.96-3.41), except among women acquiring HIV via intravenous drug use (IDU), where this association was strongly attenuated (adjOR: 0.03; 95% CI: 0.01-0.35). Baseline CD4, ART experience and age showed no significant associations.

Conclusions: The relationship between higher baseline HIV viral load and improved IR differed by HIV acquisition mode, suggesting the importance of tailored interventions addressing social determinants and immune activation. This potential interaction needs to be validated in future studies, also including sex-specific variables.