Vaccine hesitancy and anti-vaccination attitudes during the start of COVID-19 vaccination program: a content analysis on Twitter data

BackgroundVaccine hesitation, which is defined as one of the most important global health threats by World Health Organization, maintains its universal importance during the COVID-19 period. Due to the increasing appearance of anti-vaccine arguments on social media, Twitter is a useful resource in detecting these contents. In this study, we aimed to identify the prominent themes about vaccine hesitancy and refusal on social media during the COVID-19 pandemic. MethodsIn this qualitative study we collected Twitter contents which contain a vaccine-related keywords and published publicly between 9/12/2020 and 8/1/2021 (n=551,245). A stratified random sample (n=1041) is selected and analyzed by four researchers with content analysis method. ResultsAll tweets included in the study were shared from 1,000 unique accounts of which 2.7% were verified and 11.3% organizational users. 90.5% of the tweets were about vaccines, 22.6% (n=213) of the tweets mentioned at least one COVID-19 vaccine name and the most frequently mentioned COVID-19 vaccine was CorronaVac (51.2%). Yet, it was mostly as "Chinese vaccine" (42.3%). 22.0% (n=207) of the tweets included at least one anti-vaccination theme. Among tweets that included an anti-vaccination theme; poor scientific processes (21.7%), conspiracy theories (16.4%), and suspicions towards manufacturers (15.5%) were the most frequently mentioned themes. The most co-occurred themes were "Poor scientific process" theme come along with "suspicion towards manufacturers" (n=9) and "suspicion towards health authorities" (n=5). ConclusionsThis study may be helpful for health managers to identify the major concerns of the population and organize the preventive measures, through the significant role of social media on early information about vaccine hesitancy and anti-vaccination attitudes.

Contrast- and illumination-invariant object recognition from active sensation.

It has been suggested that the deleterious effect of contrast reversal on visual recognition is unique to faces, not objects. Here we show from priming, supervised category learning, and generalization that there is no such thing as general invariance of recognition of non-face objects against contrast reversal and, likewise, changes in direction of illumination. However, when recognition varies with rendering conditions, invariance may be restored and effects of continuous learning may be reduced by providing prior object knowledge from active sensation. Our findings suggest that the degree of contrast invariance achieved reflects functional characteristics of object representations learned in a task-dependent fashion.

Structural and view-specific representations for the categorization of three-dimensional objects.

It has been debated whether object recognition depends on structural or view-specific representations. This issue is revisited here using a paradigm of priming, supervised category learning, and generalization to novel viewpoints. Results show that structural representations can be learned for three-dimensional (3D) objects lacking generalized-cone components (geons). Metric relations between object parts are distinctive features under such conditions. Representations preserving 3D structure are learned provided prior knowledge of object shape and sufficient image input information is available; otherwise view-specific representations are generated. These findings indicate that structural and view-specific representations are related through shifts of representation induced by learning.

Development of configural 3D object recognition.

There is evidence for the late development in humans of configural face and animal recognition. We show that the recognition of artificial three-dimensional (3D) objects from part configurations develops similarly late. We also demonstrate that the cross-modal integration of object information reinforces the development of configural recognition more than the intra-modal integration does. Multimodal object representations in the brain may therefore play a role in configural object recognition.