Predictors of COVID-19 Vaccine Uptake among Adults in Kiambu, Kenya

Introduction: COVID-19 continues to pose a major public health challenge, contributing to a significant global disease burden and economic disruption, particularly in low- and middle-income countries. The widespread rollout of COVID-19 vaccines remains a crucial strategy for controlling the pandemic. However, vaccine uptake has remained low in many regions despite efforts of the World Health Organization (WHO), pharmaceutical companies, and other stakeholders. In Kenya, there has been limited research identifying predictors of the COVID-19 vaccine uptake among adults. This study aimed to determine the level of vaccine uptake and identify the predictors associated with COVID-19 vaccine uptake in Central Kenya. Methods: This study adopted a community-based cross-sectional design. A total of 537 adult participants residing in Kiambu County were recruited from selected sub-counties using a multi-stage sampling technique. Participants were identified and enrolled at their households. We conducted an ordinal logistic regression analysis to identify the predictors associated with COVID-19 vaccine uptake. Results: Of the 537 participants, 421 (78%) had received at least one dose of the COVID-19 vaccine, with 366 (68%) completing the vaccination series. Participants aged 18 - 30 years (adjusted odds ratio [aOR] = 0.50; 95% confidence interval [CI]: 0.30 - 0.83; p < 0.001) and those aged 31 - 45 years (aOR = 0.46; 95% CI: 0.28 - 0.74; p = 0.002) had significantly lower odds of the COVID-19 vaccine uptake by 50% and 54% respectively. Believing the COVID-19 vaccine would not protect from infection was associated with a 76% reduction in vaccine uptake (aOR = 0.24; 95% CI: 0.16 - 0.35; p < 0.001). Additionally, concern about vaccine side effects was associated with a 41% reduction in vaccine uptake (aOR = 0.59; 95% CI: 0.40 - 0.87; p = 0.008). Conclusion: COVID-19 vaccine uptake remains suboptimal, particularly among younger adults. The vaccine uptake was positively associated with increasing age and negatively associated with the belief that the COVID-19 vaccine will not protect from infection and concerns about vaccine side effects. Targeted interventions addressing these concerns, particularly among younger populations, are crucial to improving vaccine coverage and enhancing community-level protection.