Although vaccination is a cost-effective, equitable, and impactful public health intervention in curbing the spread of infectious disease, low uptake is a significant concern, especially among high-risk population groups. Nearly half of the population is unvaccinated in Nairobi, yet there is a shortage of vaccination information on vulnerable tuberculosis (TB) patients. The interplay of factors influences uptake, and protecting this vulnerable group and the general population from severe disease, hospitalization, and deaths is worthy. The purpose of this study is to determine the prevalence and individual-level enablers and barriers to COVID-19 vaccine uptake among adult TB patients attending selected clinics in Nairobi County, Kenya. This cross-sectional mixed-method study was conducted at TB clinics across six sub-counties in Nairobi County. It included 388 participants sampled from each clinic’s TB register. Quantitative data was collected using a questionnaire, and qualitative data was collected through key informant interviews and focus group discussions. Quantitative data was analyzed using descriptive statistics (frequencies and percentages for categorical variables and mean standard deviation for continuous variables) and inferential statistics (logistic regression). Qualitative data was analyzed through deductive coding and thematic analysis. The prevalence of COVID-19 vaccination was 46.1%, with 38.1% receiving complete vaccination. Mistrust in vaccine management (adjusted odds ratio (aOR)= 0.075, 95% confidence interval (CI): 0.025-0.229, p <0.001) was a significant barrier to COVID-19 vaccine uptake. Perceived covid-19 susceptibility (aOR = 2.901, 95% CI: 1.258-6.688, p = 0.012) and perceived covid-19 seriousness (aOR = 3.294, 95% CI: 1.130-9.604, p = 0.029) were significant enablers of COVID-19 vaccine uptake. Qualitative themes related to individual-level barriers and enablers of COVID-19 vaccine uptake were fear of side effects, stigma, myths, and mistrust in the messaging for barriers and desire to protect others and risk perception as enablers. The study revealed critical individual-level factors related to COVID-19 vaccine uptake.

Design and setting

The study was an analytical cross-sectional study based on a mixed method (quantitative and qualitative) approach. Research assistants started with collecting quantitative data and later assisted investigators in conducting the interviews. The study was conducted at six sites in Nairobi County, Kenya. 

Sample and sampling

The study targeted adult TB patients receiving treatment between certain months in 2023, EPI logisticians, and TB coordinators. Those eligible consented participants were helped to fill out the electronic questionnaires and focus group discussions (FGD) with different participants later. The EPI logisticians and TB coordinators were the main targets for key informant interviews. The study excluded newly diagnosed TB patients or those initiated on TB treatment on the day of data collection, patients who refused or were unable to state their vaccination status, and patients who were too unwell to participate. The Cochran formula was used to calculate the sample size. Proportion sampling (PPS) was used to allocate proportions to health facilities in Nairobi County. Purposive sampling was employed to identify facilities with high TB patient numbers across the six sub-counties. Proportion sampling (PPS) was used to allocate proportions to each health facility. Simple random sampling was used to select participants for the FGDs, and purposive sampling for the Key Informant Interview (KII).

Data collection tools

A semi-structured electronic questionnaire was used to collect quantitative data. It had sections A (social demographic information and vaccination details) and B (individual-level factors and COVID-19 vaccine uptake). Pre-testing of the tool was done using 12 TB patients at [redacted] which assisted in the re-ordering of questions, replacement of ambiguous words, and kobo installations on research assistants' phones. This site had population characteristics similar to those of the study sites. A KII guide and an FGD guide were used to collect qualitative data. Both guides have open-ended questions focusing on themes related to the study objectives.

Data collection

Eight research assistants administered the semi-structured electronic questionnaire face-to-face with participants during their clinic visits. Two research assistants were allocated to [redacted] and [redacted] because of the number of participants, and one research assistant was assigned to the other four facilities. Participants provided informed consent before answering the questionnaire. Each research assistant had their smartphone with the questionnaire accessed via the Kobo collect application and responses were entered as provided by the participants. Six KIIs were conducted with managers and leaders in charge of the selected TB clinics, and six FGDs were held with adult TB patients from the six TB clinics. A series of open-ended questions guided the KIIs and FGDs. The interviews and FDGs took between 20-60 minutes and were audio-recorded. The verbatim recordings were manually transcribed and organized for a thematic analysis approach. The results of the interviews were triangulated with quantitative data.