Investigating Canadian Public Attitudes Toward COVID-19 Vaccine Mandates with a Nested Analysis Framework.

BACKGROUND: Social media is an important medium for studying public attitudes toward COVID-19 vaccine mandates in Canada, and Reddit network communities are a good source for this. METHODS: This study applied a "nested analysis" framework. We collected 20378 Reddit comments via the Pushshift API and developed a BERT-based binary classification model to screen for relevance to COVID-19 vaccine mandates. We then used a Guided Latent Dirichlet Allocation (LDA) model on relevant comments to extract key topics and assign each comment to its most relevant topic. RESULTS: There were 3179 (15.6%) relevant and 17199 (84.4%) irrelevant comments. Our BERT-based model achieved 91% accuracy trained with 300 Reddit comments after 60 epochs. The Guided LDA model had an optimal coherence score of 0.471 with four topics: travel, government, certification, and institutions. Human evaluation of the Guided LDA model showed an 83% accuracy in assigning samples to their topic groups. CONCLUSION: We develop a screening tool for filtering and analyzing Reddit comments on COVID-19 vaccine mandates through topic modelling. Future research could develop more effective seed word-choosing and evaluation methods to reduce the need for human judgment.

Patients with von Willebrand disease in China: Results of an online survey.

INTRODUCTION: Little is known about the clinical characteristics of von Willebrand disease (VWD) patients in China, the impact of Covid-19 on them and their genetic mutation. AIM: To describe the clinical characteristics of a group of VWD patients in China, the impact of Covid-19 on them and their genetic mutation. METHODS: An online survey using a self-designed questionnaire was conducted among patients within a WeChat group of VWD patients in China. Data were analysed using t-test, the Chi-square test, Fisher's exact test and rank sum test. RESULTS: Data from a total of 96 patients were collected. Several important findings are yielded. Above all, type 3 patients accounted for over half of the surveyed patients. Secondly, a surprising rate (>40%) of patients had experience of being misdiagnosed. Thirdly, treatment regimens were dominated by cryoprecipitate, blood-derived FVIII and plasma, and only a small percentage of patients received prophylaxis. Fourthly, we identified 17 new von Willebrand factor (VWF) mutant genes which merit further investigation. Additionally, Covid-19 was found to pose some challenges for the patients. CONCLUSION: In China, the high rates of type 3 patients and misdiagnosis suggest that most of the VWD patients may never be diagnosed in China. When it comes to diagnosis and treatment, there is a large gap between developing countries like China and developed countries.