Valproic acid could help in the fight against COVID-19: A case-control study

There is early evidence about Valproic acid (VPA) antiviral effect. Our aim was to investigate the incidence and severity of SARS-CoV-2 infection in VPA users as compared with the general population.

A case-control study nested within a cohort, carried out between March 1 and December 17, 2020. Retrospectively, we identified confirmed SARS-CoV-2 infection patients exposed to VPA in our health department (defined as case). We ascertained VPA regimen (all the time (AT) (292 days) or at least 20% of the study period (notAT) (≥58 days) and if VPA levels were in therapeutic range (ATR) (50-100mcg/mL) in the last 24 months. We calculated the cumulative incidence of SARS-CoV-2 infection and hospital admission in the cases, comparing it with the general unexposed VPA population (controls).

During the study period, 6183 PCR+ were detected among 281,035 inhabitants, of these, 746 were hospitalized. 691 patients were on VPA notAT and 628 (90.1%) AT. The indication for VPA use was epilepsy in 54.9%. The incidence of PCR+ was 1.736% (OR 0.785 (95%CI 0.443-1.390) and 1.910% (OR 0.865 (95%CI 0.488-1.533), on VPA notAT and VPA AT patients, respectively vs. 2.201% in people without VPA regimen. Those patients with VPA ATR had a lower risk of PCR + (OR 0.233 (95%CI 0.057-0.951) notAT; OR 0.218 (95%CI 0.053-0.890) AT). Hospital admission incidence was lower in patient on VPA (OR was 0.543 (95% CI 0.076-3.871).

Patients with VPA within the therapeutic range had a reduction of SARS-Cov-2 infection incidence greater than 75%. There is a downward trend in the risk of COVID-19 admission by SARS-CoV-2 in patients on VPA therapy. These findings warrant further investigation.