Safety and Adverse Effects Related to COVID-19 Viral Vector Vaccines: A Systematic Review.

Background: There have been safety concerns regarding the COVID-19 vaccines because of their unprecedented speed of development. Therefore, systematic reviews are necessary to address these concerns and reduce public hesitancy regarding COVID-19 vaccines. This study aims to systematically review the reported adverse events related to viral vector COVID-19 vaccines.

Materials and methods: We performed a systematic search in the databases of PubMed, Scopus, Web of Science, and Cochrane on September 15^th, 2021. This study adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. The records underwent two-step title/abstract and full-text screenings, and the eligible records were included in the data extraction process. We used the Newcastle-Ottawa Scale (NOS) for the Bias Assessment of included articles.

Results: The adenovirus vector-based COVID-19 vaccines, including the Janssen COVID-19 vaccine, the AstraZeneca COVID-19 vaccine, and the Sputnik V vaccine were included in this review. Among these vaccines, the AstraZeneca has presented enormous side effects with most being systemic and a few sporadic cases of life-threatening events such as thrombosis and capillary leak syndrome and even death in a few cases. Prominent systemic side effects of the adenovirus vaccines include fever, fatigue, malaise, arthralgia, myalgia, sweating, and dizziness. Erythema, swelling, tenderness, itching, and numbness at the injection site are the most common local reactions.

Conclusion: It appeared that the frequency of serious adverse events is negligible, and vaccination to prevent severe COVID-19 and mortality has greater benefits than adverse events in the general population.