Author Contributions

Conceptualization, O.A., E.O. and M.K.N.; Methodology, C.N. (Carolyne Nasimiyu), I.N., J.D., M.D., N.L., R.N., S.O., S.A.K. and S.L.K.; Software, R.O.; Validation, M.D. and R.O.; Formal analysis, R.O. and E.O.; Investigation, J.D., C.N. (Carol Ngunu), N.L., R.N., S.O. and S.L.K.; Resources, N.L.; Data curation, R.O.; Writing—original draft, C.N. (Carolyne Nasimiyu); Writing—review & editing, C.N. (Carolyne Nasimiyu), I.N., J.D., P.A., O.O., C.N. (Carol Ngunu), H.M., J.G., M.D., N.L., R.N., S.O., S.A.K., S.L.K., S.G., L.E., M.M., O.A., R.B., E.O. and M.K.N.; Supervision, C.N. (Carolyne Nasimiyu), P.A., O.O., C.N. (Carol Ngunu), N.L., R.N., S.A.K., S.G., L.E., M.M., E.O. and M.K.N.; Project administration, H.M., S.G. and M.M.; Funding acquisition, O.A., R.B. and M.K.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the US National Institute of Allergy and Infectious Disease/National Institutes of Health (NIAID/NIH), grant number U01AI151799, through the Centre for Research in Emerging Infectious Diseases—East and Central Africa (CREID-ECA), the Consortium of Global International Agricultural Research/International Livestock Research Institute (CGIAR/ILRI) Research Program on Livestock, Rockefeller Foundation, Africa—Centers for Disease Control and Prevention. Carolyne Nasimiyu was supported by the Fogarty International Center and NIAID/NIH under grant number D43TW011519.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of the Kenya Medical Research Institute (Approval number SSC 4098). Additional approvals were obtained from the University of Nairobi Ethics and Research Committee (Approval number P223/03/2022) and the National Commission for Science, Technology, and Innovation (License number NACOSTI/P/21/13539).

Informed Consent Statement

Written informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available upon request from the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Figure 1. Map of Kenya showing the location of the two study sites: Nairobi, the capital city, and Kakamega, the rural site.

Figure 1. Map of Kenya showing the location of the two study sites: Nairobi, the capital city, and Kakamega, the rural site.

Figure 2. Frequency of the P/N ratio among urban (top panel) and rural (bottom panel) participants in Kenya, February 2022. Results were expressed as positive/negative ratios, with a value ≥ 1 considered positive. A significantly higher proportion of rural participants were more immunoreactive, suggesting recent infection or vaccination.

Figure 2. Frequency of the P/N ratio among urban (top panel) and rural (bottom panel) participants in Kenya, February 2022. Results were expressed as positive/negative ratios, with a value ≥ 1 considered positive. A significantly higher proportion of rural participants were more immunoreactive, suggesting recent infection or vaccination.

Figure 3. Sources of COVID-19 vaccine information (left panel) and the most trusted sources of COVID-19 vaccine information (right panel) among the urban and rural study participants.

Figure 3. Sources of COVID-19 vaccine information (left panel) and the most trusted sources of COVID-19 vaccine information (right panel) among the urban and rural study participants.

Figure 4. Participants’ attitudes towards the COVID-19 vaccine.

Figure 4. Participants’ attitudes towards the COVID-19 vaccine.

Table 1. Sociodemographic characteristics of all study participants.

Table 1. Sociodemographic characteristics of all study participants.

Urban Participants, N = 781Rural Participants, N = 810Characteristicn (%)95% CI (%)n (%)95% CI (%)Sex Female497 (63.6)60.0, 67.0469 (57.9)54.0, 61.0Male284 (36.4)33.0, 40.0341 (42.1)39.0, 46.0Age group (years) ≤994 (12.0)9.9, 15.0188 (23.2)20.0, 26.010–1994 (12.0)9.9, 15.0154 (19.0)16.0, 22.020–29215 (27.5)24.0, 31.096 (11.9)9.7, 14.030–39174 (22.3)19.0, 25.0108 (13.3)11.0, 16.040–4993 (11.9)9.8, 14.084 (10.4)8.4, 13.050–5965 (8.3)6.5, 11.067 (8.3)6.5, 10.060+46 (5.9)4.4, 7.8113 (14.0)12.0, 17.0Level of education Primary265 (34.1)31.0, 38.0198 (24.5)22.0, 28.0Secondary215 (27.7)25.0, 31.0116 (14.3)12.0, 17.0Post-secondary168 (21.6)19.0, 25.035 (4.3)3.1, 6.0Child102 (13.1)11.0, 16.0223 (27.6)25.0, 31.0No formal education27 (3.5)2.3, 5.1237 (29.3)26.0, 33.0Missing4 (0.5)0.1, 1.31 (0.1)0.0, 0.7Occupation Child (<18 years)159 (20.4)18.0, 23.0317 (39.1)36.0, 43.0Student44 (5.6)4.2, 7.624 (3.0)1.9, 4.4Informal employment187 (23.9)21.0, 27.046 (5.7)4.2, 7.6Formal employment35 (4.5)3.2, 6.220 (2.5)1.6, 3.9Self-employed161 (20.6)18.0, 24.0267 (33.0)30.0, 36.0Healthcare worker10 (1.3)0.65, 2.42 (0.2)0.04, 1.0Unemployed181 (23.2)20.0, 26.0126 (15.6)13.0, 18.0Other4 (0.5)0.16, 1.48 (1.0)0.6, 2.0Reported chronic illness * No668 (85.5)83.0, 88.0721 (89.0)87.0, 91.0Yes113 (14.5)12.0, 17.089 (11.0)9.0, 13.0Ever diagnosed with COVID-19 No738 (94.5)93.0, 96.0809 (99.9)99.0, 100Yes43 (5.5)4.1, 7.41 (0.1)0.01, 0.80

Table 2. Reasons for COVID-19 vaccine uptake among vaccinated urban and rural study participants.

Table 2. Reasons for COVID-19 vaccine uptake among vaccinated urban and rural study participants.

Urban Participants, N = 326Rural Participants, N = 262Reasons for COVID-19 Vaccine Uptaken (%)95% CI (%)n (%)95% CI (%)Perceived high-risk health status108 (26.7)23.0, 31.0106 (31.5)27.0, 37.0Vaccine effectiveness98 (24.9)21.0, 30.012 (4.9)2.7, 8.7GOK directive66 (18.2)14.0, 23.065 (22.0)17.0, 27.0Number of COVID-19 deaths53 (15.2)12.0, 20.060 (20.6)16.0, 26.0Employer requirement45 (13.2)9.9, 17.08 (3.3)1.6, 6.7Number of COVID-19 cases43 (12.7)9.4, 17.097 (29.6)25.0, 35.0Suggestions from healthcare workers24 (7.5)5.0, 11.035 (13.2)9.5, 18.0Suggestions from family/friends/neighbor18 (5.7)3.5, 9.14 (1.7)0.6, 4.6Advanced age11 (3.6)1.9, 6.519 (7.6)4.8, 12.0Free vaccine11 (3.6)1.9, 6.511 (4.5)2.4, 8.2Others *12 (3.9)2.1, 6.94 (1.7)0.6, 4.6

Table 3. Factors associated with COVID-19 vaccine uptake among the urban and rural study participants.

Table 3. Factors associated with COVID-19 vaccine uptake among the urban and rural study participants.

Urban ParticipantsRural ParticipantsCharacteristicaPR 195% CI 1p-ValueaPR 195% CI 1p-ValueAge group 18–30RefRef RefRef 31–401.421.05, 1.910.0211.350.88, 2.120.241–501.681.18, 2.370.0041.581.01, 2.510.04651–601.491.00, 2.180.0421.420.88, 2.310.1561+1.601.00, 2.470.0411.380.89, 2.170.2Main occupation UnemployedRefRef RefRef Self-employment1.100.80, 1.510.6 1.401.00, 2.010.060Formal employment1.681.06, 2.590.0231.600.86, 2.860.12Student1.370.81, 2.250.22.501.32, 4.600.004Informal employment1.160.85, 1.590.41.170.67, 1.950.6Healthcare worker1.790.86, 3.350.0911.040.06, 4.90>0.9Diagnosed with COVID-19 NA * NoRefRef Yes1.541.05, 2.200.021 COVID-19 Vaccine attitudes
Vaccines are important NA * Strongly Agree/AgreeRefRef Neutral0.620.33, 1.050.10 Strongly Disagree/Disagree0.230.04, 0.710.037 Vaccine protects against infection NA * No/Don’t knowRefRef Yes1.120.87, 1.440.4 Source of COVID-19 information
Social media NA * NoRefRef Yes1.261.00, 1.580.052 COVID-19 Knowledge
Vaccine protects the unvaccinatedNA * Yes RefRef No/Don’t know 0.880.68, 1.130.3Children can be vaccinatedNA * No/Don’t know RefRef Yes 1.220.95, 1.570.12Vaccine has no side effectsNA * No/Don’t know RefRef Yes 1.140.87, 1.480.4COVID-19 Vaccine attitudes
I trust the COVID-19 vaccine information from the mediaNA * Neutral RefRef Strongly Agree/Agree 1.430.81, 2.800.3Strongly Disagree/Disagree 1.470.58, 3.610.4Source of COVID-19 vaccine information
Mass MediaNA * No RefRef Yes 1.170.86, 1.610.3

Table 4. Reasons for vaccine refusal among those not vaccinated.

Table 4. Reasons for vaccine refusal among those not vaccinated.

Urban Participants, N = 122Rural Participants, N = 77Reasons for COVID-19 Vaccine Refusal *n (%)95% CIn (%)95% CIConcerns about side effects55 (45.1%)36%, 54%41 (53.2%)42%, 65%Concerns about vaccine safety36 (29.5%)22%, 39%22 (28.6%)19%, 40%Lack of vaccine information32 (26.2%)19%, 35%19 (24.7%)16%, 36%Concerns about vaccine effectiveness11 (9.0%)4.8%, 16%2 (2.6%)0.45%, 9.9%Vaccine can cause COVID-193 (2.5%)0.64%, 7.6%2 (2.6%)0.45%, 9.9%Religious reasons1 (0.8%)0.04%, 5.2%2 (2.6%)0.45%, 9.9%Cultural reasons1 (0.8%)0.04%, 5.2%2 (2.6%)0.45%, 9.9%Others **30 (24.6%)17%, 33%9 (11.7%)5.8%, 22%

Table 5. Factors associated with COVID-19 vaccine refusal among study participants.

Table 5. Factors associated with COVID-19 vaccine refusal among study participants.

Urban Participants, N = 122Rural Participants, N = 77CharacteristicaPR 195% CI 1p-ValueaPR 195% CI 1p-ValueAge group 18–30RefRef RefRef 31–401.240.80, 1.890.31.650.80, 3.370.241–500.590.20, 1.340.31.380.54, 3.520.551–601.210.61, 2.190.61.200.50, 2.900.761+0.580.14, 1.600.41.200.57, 2.510.6Level of education NA * No formal education RefRef Primary 0.660.36, 1.210.2Secondary 0.520.26, 1.040.066Post-secondary 1.020.37, 2.77>0.9Main Occupation NA * Unemployed RefRef Self Employed 0.730.44, 1.220.2Employed 0.760.15, 3.780.7Student 1.740.55, 5.530.3Informal Employment 0.200.05, 0.880.033Healthcare worker 0.000.00, Inf>0.9Willing to pay for vaccine privately NA * Neutral RefRef Strongly Disagree/Disagree 1.460.69, 3.110.3Strongly Agree/Agree 0.550.14, 2.160.4Trust in vaccine information from the media