Predictors of COVID-19 vaccination uptake and reasons for decline of vaccination: a systematic review

Background: Various COVID-19 vaccines with proven safety and effectiveness are available now but vaccine hesitancy remains a public threat. COVID-19 vaccines uptake appears to have an essential role in the successful control of the COVID-19 pandemic. Objective: To examine predictors of COVID-19 vaccination uptake and reasons for decline of vaccination. Methods: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines for this systematic review. We searched Medline, PubMed, Web of Science, Scopus, ProQuest, CINAHL, and a pre-print service (medRxiv) from inception to July 12, 2021. We used the following key-words: vaccin*, COVID-19, and uptake. We included all types of studies (quantitative, qualitative, and mixed methods) reporting COVID-19 vaccination uptake. The review protocol was registered with PROSPERO (CRD42021267460). Results: Twelve studies met the inclusion and exclusion criteria. COVID-19 vaccination uptake ranged from 28.6% to 98% in the general population, while among healthcare workers ranged from 33.3% to 94.5%, and among patients ranged from 36% to 80%. The main predictors of COVID-19 vaccination uptake were male gender, white race, older age, higher socioeconomic status, higher self-perceived COVID-19 vulnerability, increased information about COVID-19 vaccines, and chronic illness. The most important reasons for decline of vaccination were concerns about the safety and effectiveness of vaccines, illness, medication, pregnancy, fertility, breastfeeding, religious reasons, ethical reasons, previous COVID-19 diagnosis, self-estimation that COVID-19 is not a severe disease, and limited knowledge about the vaccines. Conclusions: Several factors affect COVID-19 vaccination uptake, while various reasons affect people decision to refuse to take a COVID-19 vaccine. These findings are essential to further enhance our understanding of COVID-19 vaccination uptake and design specific interventions. Given the high prevalence of COVID-19 vaccine hesitancy, our findings have major implications for the delivery of COVID-19 vaccination programmes in the public with special attention to people who are undecided or unlikely to take a COVID-19 vaccine.