Public's perspective on COVID-19 adenovirus vector vaccines after thrombosis with thrombocytopenia syndrome (TTS) reports and associated regulatory actions: A cross-sectional study in six EU member states

Objective: In 2021, thrombosis with thrombocytopenia syndrome (TTS) was confirmed by the European Medicines Agency (EMA) as a rare side effect of the COVID-19 adenovirus vector vaccines Vaxzevria® and Jcovden®. This study aimed to describe the public's knowledge of TTS and how it affected the willingness to be vaccinated with COVID-19 vaccines and other vaccines in six European countries. Methods: From June to October of 2022, a multi-country cross-sectional online survey was conducted in Denmark, Greece, Latvia, Netherlands, Portugal, and Slovenia. The minimum target of participants to be recruited was based on the size of the country's population. The results were analysed descriptively. Results: In total, 3794 respondents were included in the analysis; across the six countries, 33.3 %–68.3 % reported being familiar with signs and symptoms of TTS, although 3.1–61.4 % of those were able to identify the symptoms correctly. The reported changes in willingness to be vaccinated against COVID-19 and with other vaccines varied per country. The largest reported change in the willingness to be vaccinated with Vaxzevria® and Jcovden® was observed in Denmark (61.2 %), while the willingness to be vaccinated with other COVID-19 vaccines changed most in Slovenia (30.4 %). The smallest decrease in willingness towards future vaccination against COVID-19 was reported in the Netherlands (20.9 %) contrasting with the largest decrease observed in Latvia (69.1 %). Conclusion: Knowledge about TTS seemed to have influenced the public's opinion in Europe resulting in less willingness to be vaccinated with Vaxzevria® and Jcovden®. Willingness for vaccination against COVID-19 with other vaccines and widespread use of vaccines to prevent other diseases also differed and seemed to be determined by the approaches taken by national health authorities when reacting to and communicating about COVID-19 vaccination risks. Further investigation of optimal risk communication strategies is warranted

COVID-19 Vaccination Coverage and Factors Influencing Vaccine Hesitancy among Patients with Inborn Errors of Immunity in Latvia: A Mixed-Methods Study

Background: The European Society for Immunodeficiencies recommends that all patients with inborn errors of immunity (IEI) without contraindications should receive SARS-CoV-2 vaccination. The aim of this study was to investigate the reasons that discourage IEI patients from receiving the recommended vaccination and to assess vaccination coverage among IEI patients in Latvia. Methods: In this multicenter mixed-methods study, the vaccination status of all patients with IEI within two tertiary centers in Latvia was reviewed using electronic health records. Semi-structured interviews were conducted with 16 IEI patients who did not undergo vaccination, and a thematic analysis was performed. Results: A total of 341 patients (49.3% female; median age 19.7 years (IQR:17)) were included in the quantitative part. The proportion of fully vaccinated individuals aged ≥ 12 years was 66.8%–70.9% with patients with selective IgA deficiency and 58.8% with other IEI (χ² = 14.12, p p < 0.001). The five main themes identified were as follows: (1) fear and uncertainty; (2) risk and benefit assessment: COVID-19 vaccine—is it worth it? (3) external influences: the dark horse of the decision-making—people around us; (4) individuals against the system; and (5) beliefs about vaccination and COVID-19. Under-representation of certain IEI groups and recall bias are possible limitations of this study. Conclusions: While most reasons for hesitancy were similar to those previously described in the general population, disease-specific concerns were also identified