This study investigated humoral immunity to mRNA-based COVID-19 vaccines after a booster dose in patients with psoriasis treated with biologics or methotrexate. We observed an increase in humoral responses in both patients and control participants after a booster vaccine. At 12 months, both groups showed positive humoral responses, but patients had significantly lower levels of IgG and neutralizing indexes than the control group. It is unknown if the observed difference has clinical relevance.