BACKGROUND: Gam-COVID-Vac is the world's first registered vector vaccine against COVID-19 based on a combination of two heterologous adenoviruses. It was chosen by the Republic of San Marino as the main tool in its vaccination campaign, which started on 25 February 2021. Our aim was to build up on the ROCCA study, focused on the older population, by describing adverse effects following immunisation (AEFIs) rates and characteristics in all age groups for the first time in a real-world context. METHODS: An active surveillance study on recipients of at least one dose of the Gam-COVID-Vac vaccine was conducted. Participants were administered online questionnaires through live/phone interviews with physicians, by e-mail or by scanning a QR code at different points in time after the first dose: one week (Q1) one month (Q2), and three months (Q3) between March and August 2021. FINDINGS: Overall, 6190 vaccine recipients were recruited. Mean age was 52·4 ± 18·2 years. After the first dose, systemic reactions were reported by 57·5% of the participants, while injection site reactions were reported by 46·7%. The most common AEFIs were pain at the injection site, fatigue and headache. Grade 3 or 4 AEFIs were reported by 0·8% and 0·3% of the participants, respectively. After the second dose, systemic reactions were reported by 63·1% of the participants, while injection site reactions by 54·7%. The most common AEFIs were malaise, pain at injection site and myalgia. Grade 3 or 4 AEFIs were reported by 2·7% and 1·1% of the participants, respectively. Multivariate analysis showed younger age, being a woman and food allergies are risk factors for more severe AEFIs. INTERPRETATION: Our results confirm a good tolerability profile for the population aged 18 and over providing useful data for vaccination campaigns ongoing in countries planning to use Gam-COVID-Vac. FUNDING: None.
ROCCA cohort study: Nationwide results on safety of Gam-COVID-Vac vaccine (Sputnik V) in the Republic of San Marino using active surveillance