Barriers to COVID-19 vaccine surveillance: the issue of under-reporting adverse events

Exploring the relationship between experience of vaccine adverse events and vaccine hesitancy: A scoping review

Fear of side effects is the main motive for vaccine refusal. However, before the COVID-19 pandemic, little attention had been paid to the actual experience of adverse events and its relationship with vaccine hesitancy. This scoping review aimed to analyze the impact of VH on EAE and vice versa. We reviewed 55 articles. Most of the studies focused on COVID-19 vaccination and employed cross-sectional surveys with self-reported indicators. These studies identified significant correlations between EAE and VH. Social cognitive models shed some light on the influence of EAE on VH, while the converse is usually explained by the nocebo effect that predominately accounts for the converse. This emerging research field is hampered by significant inconsistencies in theoretical explanations, assessments of the relationship, and measurements of these two phenomena. A more comprehensive consideration of individual experience, both objective and subjective, would help develop more effective vaccine communication strategies and improve pharmacological surveillance.

Serious adverse drug reactions associated with anti-SARS-CoV-2 vaccines and their reporting trends in the EudraVigilance database

A serious adverse reaction (SADR) may follow a vaccination against SARS-CoV-2 infection. We aimed to explore symptoms and reporting trends of SADRs to anti-SARS-CoV-2 vaccines based on the EudraVigilance database. This retrospective observational study analysed 250,966 suspected SADRs (with 62.8% reported in females), following the administration of 733,837,251 vaccine doses against SARS-CoV-2. Pfizer BioNTech (Comirnaty-Tozinameran), Moderna (Spikevax-Elastomeran), Janssen (Jcovden) and AstraZeneca (Vaxzevria) vaccines were analysed. The assessment included 897 types of SADRs across 12 categories. The most common clinical manifestations of SADRs to anti-SARS-CoV-2 vaccines vaccines encompassed neuropsychiatric (n = 121,877), cardiovascular (n = 78,167), as well as musculoskeletal and connective tissue disorders (n = 63,994). After summarising all SADRs, vaccination with Comirnaty was associated with the lowest risk of experiencing SADRs (754/million administered doses), followed by Spikevax (785/million doses), Jcovden (1,248/million doses) and Vaxzevria (2,301/million doses; p < 0.001). Regarding the vaccine administration timelines, the reporting of SADRs tends to be delayed and occurs over a longer time (p < 0.001). SADRs associated with anti-SARS-CoV-2 vaccines seem to be relatively rare. Compared to adenovirus-based vector vaccines (Jcovden, Vaxzevria), mRNA vaccines appear to offer improved safety profiles (Comirnaty, Spikevax). The risk of SADR to any SARS-CoV-2 vaccine seems to be outweighed by the benefits of active immunization against the virus.

Cardiac adverse drug reactions to COVID-19 vaccines. A cross-sectional study based on the Europe-wide data

AIMS

We aimed to analyse serious cardiac adverse drug reactions to COVID-19 vaccines from the Europe-wide EudraVigilance database.

METHODS AND RESULTS

In this retrospective, cross-sectional study, the EudraVigilance database was searched to identify suspected serious cardiac post-vaccination adverse drug reactions to COVID-19 vaccines. This data was coupled with the number of total vaccine doses administered in the European Economic Area for Comirnaty (Pfizer BioNTech), Spikevax (Moderna), Vaxzevria (AstraZeneca), Jcovden (Janssen), Nuvaxovid (Novavax), products, available from the European Centre for Disease Prevention and Control 'Vaccine Tracker' database. The analysis included 772 228 309 administered doses of eligible vaccines from the 'Vaccine Tracker' database and 86 051 eligible records of cardiac adverse drug reactions from the EudraVigilance database. The frequency of most of the investigated adverse drug reactions was very rare (<1/10 000 i.e. <100/1 000 000 doses). The lowest risk of any serious cardiac adverse drug reactions was noticed for vaccination with Comirnaty (135.5 per million doses), while Spikevax, Jcovden, Vaxzevria, and Nuvaxovid were characterized by higher risk (respectively, 140.9, 194.8, 313.6, and 1065.2 per million doses). The most common complications of vaccinations included syncope, arrhythmia, tachycardia, palpitations, angina pectoris, hypertension, myocarditis, thrombosis, and pulmonary embolism.

CONCLUSION

The risk of serious cardiac adverse drug reactions to COVID-19 vaccines is low and the benefit of active immunization against that disease seems to outweigh the potential risk of serious post-vaccination cardiac adverse drug reactions.