With the advent of social networking sites, the so-called health dissidents have received unprecedented possibilities for online community building and spreading their views. In particular, the combination of social uncertainty and the platform affordances that bordered antivaxxer communities from outer communication led to formation of (allegedly) closed-up online milieus where vaccination denialists’ (‘antivaxxers’) irrational views resided and grew. The deliberative counter-productivity of such communities needs to be investigated. In this respect, Russia is a special case, characterized by low trust in the public sphere as a ground for the spread of conspiracy theories, and by ‘mixed’ trust to the healthcare system, thanks to highly-reputable Soviet-time medical services but negative attitudes to the current ones. We look at @anti_ covid21, the largest Russian pandemic antivaxxer community on Telegram, to explore by what means destructive opinions accumulate in this community. We investigate the combination of three discursive elements usually studied separately in research on COVID-19 denialism: 1) distrust, including its addressees, and interconnectedness of the destructive features of the antivaxxer discourse, namely distrust, aggression, and conspiracy thinking; 2) the patterns of micro-opinion cumulation that lead to general growth of distrust; 3) content sourcing that supports ‘the discourse of distrust.’ We follow the conceptual framework of cumulative deliberation; it implies that micro-acts of opinionated participation matter both en masse and in deliberative micro-patterns. Our sample includes all posts and comments from @anti_covid21 of six months of 2021, with 1,185 posts and 282,000+ comments altogether. Out of this sample, three datasets were formed. In particular, Dataset 1 was received by semi-automatedly reducing from 282,000+ to 12,188+ texts and then coded by 28 coders. Dataset 2 comprised comment threads of three most active days in terms of commenting, of 411 comments altogether, that were coded as continuous samples by 6 additional coders. Dataset 3 consisted of the 1,185 posts in which the available attracted content (text, photo, or video) was coded by 4 coders on its formal belonging to certain media types and countries of origin. Our results show that @anti_covid21 was a reactive community centered around one-sided anti-vaccination content that left no room for multi-view discussing. Content sourcing united user-generated evidence, criticized mainstream media pieces, and publications of blurred origin of many countries, making the community open to world experience but of highly biased nature. The ‘discourse of distrust’ that emerged in response was politicized, distrust to national and global actors potentially being a mediator to vaccine distrust. We identified two stable micro-patterns of accumulation of distrust triggered by both the published content and user behavior. Altogether, our conclusions differ from other countries’ experiences and call for pre-emptive resolution of the multi-faceted issue of social distrust before new health crises erupt.