background: There is no study specifically focused on SARS-CoV-2 vaccine in primary Sj?gren's syndrome (pSS). objective: To assess the immunogenicity, safety, possible effects on disease activity, and autoantibody profile of the Sinovac-CoronaVac vaccine in pSS. methods: Fifty-one pSS patients and 102 sex- and age-balanced controls without autoimmune diseases were included in a prospective phase 4 trial of the Sinovac-CoronaVac vaccine (two doses 28?days apart, D0/D28). Participants were assessed in three face-to-face visits (D0/D28 and six weeks after the 2nd dose (D69)) regarding adverse effects; clinical EULAR Sj?gren's Syndrome Disease Activity Index (clinESSDAI); anti-SARS-CoV-2 S1/S2 IgG (seroconversion (SC) and geometric mean titers (GMT)); neutralizing antibodies (NAb); and pSS autoantibody profile. results: Patients and controls had comparable female sex frequency (98.0% vs. 98.0%, p?=?1.000) and mean age (53.5?±?11.7 vs. 53.4?±?11.4?years, p?=?0.924), respectively. On D69, pSS patients presented moderate SC (67.5% vs. 93.0%, p??0.05). conclusions: Sinovac-CoronaVac vaccine is safe in pSS, without a deleterious impact on disease activity, and has a moderate short-term humoral response, though lower than controls. Thus, a booster dose needs to be studied in these patients. background: ClinicalTrials.gov Identifier: NCT04754698. Key Points ? Sinovac-CoronaVac vaccine is safe in pSS, without a detrimental effect on systemic disease activity, and has a moderate short-term humoral response ? A booster dose should be considered in these patients.