 This study aimed to investigate mild adverse events, AEs, of the COVID-19 vector vaccine GAMCOVIDVAC, Sputnik V, based on a participatory trial conducted on telegram in the Russian language. The study collected a unique dataset consisting of 11,500 and 15 self-reported Sputnik V vaccine AEs posted on the telegram group, and utilized natural language processing methods to extract AEs. The results showed that Russian telegram users reported mostly pain, fever, and fatigue after the Sputnik V vaccination, and the Sputnik V AE profile was comparable with other vector COVID-19 vaccines. The study concludes that social media discourse could provide meaningful information about the AE profile of novel vaccines. This article was authored by Andrei Jarinowski, Aleksandr Semyonov, Mikolai Kaminsky, and others.