Putative bloodmeal sources in Glossina austeni tsetse fly of Arabuko Sokoke National Reserve in Kenya.

Tsetse flies, the sole biological vectors of trypanosomiasis, are predominantly controlled using visual traps and targets baited with attractant lures. Formulation of the lures is informed by compositions of odors from vertebrate hosts preferred by specific tsetse species. However, there are no effective lures for Glossina austeni, a major vector of trypanosomiasis along eastern-coastal region of Africa. Formulation of the lure can be informed by knowledge of G. austeni, preferred vertebrate hosts. We thus sought to understand these hosts by assessment of putative bloodmeal sources of this tsetse fly in Arabuko Sokoke National Reserve where this species is naturally present. We sampled tsetse flies using NGU traps, isolated non-teneral G. austeni flies based on their feeding status, and identified vertebrate source of bloodmeals in their midgut contents using vertebrate 16S rRNA-PCR High-Resolution Melting analysis. We analyzed the relative vertebrate species frequencies in the bloodmeals using Fisher's exact tests. Overall, we trapped 122 flies, most of which (66.39%) were non-teneral, among which we successfully identified the vertebrate bloodmeals in 30 samples. Specifically, we detected putative suni antelope (Neotragus moschatus), harnessed bushbuck (Tragelaphus scriptus), buffalo (Syncerus caffer) and cattle (Bos taurus) derived bloodmeals. Putative suni antelope bloodmeals were significantly more frequent (63.22%), than those of the harnessed bushbuck (23.33%), buffalo (10.00%) or cattle (3.33%) (p < 0.05 Fisher's exact tests) among the samples analyzed. Suni antelope thus appears to predominate vertebrate bloodmeal source for G. austeni in the reserve, coincident with findings reported elsewhere, and is therefore a viable candidate for bioprospecting for G. austeni responsive attractants.

The long-term impact of HIV/AIDS on socio-economic status: a comparative analysis of households headed by HIV-positive and HIV-negative individuals in Western Kenya.

HIV/AIDS is known to have adverse effects on individual and family socio-economic status due to the loss of productive time and over-expenditure in treatment. However, empirical data on how HIV/AIDS affects households' socio-economic status are insufficient. We linked socio-economic data from a Health and Demographic Surveillance System (HDSS) that implements an HIV/AIDS Longitudinal bio-behavioural survey (LBBS) to understand the long-term impact of HIV/AIDS on households' socio-economic status between 2010 and 2018. We compared changes in socio-economic status between households headed by HIV-negative and -positive individuals. A logistic regression was used to assess factors that influence socio-economic status. The level of education and household size were not significant predictors of households' socio-economic status. Households headed by HIV-positive individuals could maintain their baseline socio-economic status (unadjusted RRR = 1.17, 95% CI: 1.01, 1.36) but improvement chances were reduced despite a non-significant association (unadjusted RRR = 0.98, 95% CI: 0.80, 1.20). While HIV/AIDS is known to disrupt economic growth, in this setting, being a male household head, old and widowed reduces chances of improved socio-economic status. The elderly people, widows and widowers are disadvantaged. Consequently, there is a need for special programmes, which seek to empower the identified vulnerable groups economically. .

Bloodmeal host identities among sympatric Glossina austeni and Glossina pallidipes tsetse flies in Shimba Hills National Reserve, Kwale, Kenya.

Odor from preferred/non-preferred tsetse fly vertebrate hosts have been exploited in R&D of attractants/repellents of the fly for human and livestock protection. Odors from vertebrate hosts of Glossina austeni and Glossina pallidipes tsetse flies can facilitate formulation of novel attractants effective against G. austeni or improvement of existing attractant blends for G. pallidipes. We compared vertebrate blood meal sources of both fly species at Shimba Hills National Reserve, Kenya, to establish putative preferred host of either species, hence potential source of G. austeni or G. pallidipes specific odors. We trapped sympatric adult flies in 2021 and 2022 using NGU traps/sticky panels baited with POCA, collected their blood meals and characterize the meals using HRM vertebrate 16S rRNA- PCR (for host identification), and compared host profiles using GLM and Fisher's exact tests. We collected 168 and 62 sympatric G. pallidipes and G. austeni with bloodmeal, respectively in 2021 and, 230 and 142 respectively in 2022. In 2021, we identified putative hosts of 65.48 and 69.35 % of the G. pallidipes and G. austeni respectively and 82.61 and 80.28%, respectively in 2022. In 2021, we detected harnessed bushbuck, buffalo, common warthog and cattle putative host bloodmeals, and additionally bushpig and suni antelope bloodmeals in 2022. Putative vertebrate bloodmeal sources were significantly different by tsetse fly species (χ2(1, N=457) = 43.215, p < 0.001) and sampling year (χ2(1, N=457) = 8.044, p = 0.005). Frequency of common warthog bloodmeals was higher in G. pallidipes (65.79 %) than G. austeni (38.60%), and that of suni antelope and harnessed bushbuck putative bloodmeals higher in G. austeni (21.05-28.07%) than in G. pallidipes (6.84 - 17.37%) in 2022. There was an apparent change in putative feeding preference/host choices in both fly species between 2021 and 2022. Host bloodmeals in G. pallidipes or G. austeni predominantly from putative harnessed bushbuck, suni antelope or common warthog reveal these vertebrates with potential odors that can be harnessed and formulated into appropriate attractants for respective species and integrated into routine control regiment for G. pallidipes and/or G. austeni.

Anti-Severe Acute Respiratory Syndrome Coronavirus 2 Immunoglobulin G Antibody Seroprevalence Among Truck Drivers and Assistants in Kenya.

In October 2020, anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G seroprevalence among truck drivers and their assistants (TDA) in Kenya was 42.3%, higher than among healthcare workers and blood donors. Truck drivers and their assistants transport essential supplies during the coronavirus disease 2019 pandemic, placing them at increased risk of being infected and of transmitting SARS-CoV-2 over a wide geographical area.

Experiences and lessons learned from the real-world implementation of an HIV recent infection testing algorithm in three routine service-delivery settings in Kenya and Zimbabwe.

INTRODUCTION: Testing for recent HIV infection can distinguish recently acquired infection from long-standing infections. Given current interest in the implementation of recent infection testing algorithms (RITA), we report our experiences in implementing a RITA in three pilot studies and highlight important issues to consider when conducting recency testing in routine settings. METHODS: We applied a RITA, incorporating a limited antigen (LAg) avidity assay, in different routine HIV service-delivery settings in 2018: antenatal care clinics in Siaya County, Kenya, HIV testing and counselling facilities in Nairobi, Kenya, and female sex workers clinics in Zimbabwe. Discussions were conducted with study coordinators, laboratory leads, and facility-based stakeholders to evaluate experiences and lessons learned in relation to implementing recency testing. RESULTS: In Siaya County 10/426 (2.3%) of women testing HIV positive were classified as recent, compared to 46/530 (8.7%) of women and men in Nairobi and 33/313 (10.5%) of female sex workers in Zimbabwe. Across the study setting, we observed differences in acceptance, transport and storage of dried blood spot (DBS) or venous blood samples. For example, the acceptance rate when testing venous blood was 11% lower than when using DBS. Integrating our study into existing services ensured a quick start of the study and kept the amount of additional resources required low. From a laboratory perspective, the LAg avidity assay was initially difficult to operationalise, but developing a network of laboratories and experts to work together helped to improve this. A challenge that was not overcome was the returning of RITA test results to clients. This was due to delays in laboratory testing, the need for multiple test results to satisfy the RITA, difficulties in aligning clinic visits, and participants opting not to return for test results. CONCLUSION: We completed three pilot studies using HIV recency testing based on a RITA in Kenya and Zimbabwe. The main lessons we learned were related to sample collection and handling, LAg avidity assay performance, integration into existing services and returning of test results to participants. Our real-world experience could provide helpful guidance to people currently working on the implementation of HIV recency testing in sub-Saharan Africa.

Impact of mobile phone delivered reminders and unconditional incentives on measles-containing vaccine timeliness and coverage: a randomised controlled trial in western Kenya.

INTRODUCTION: Short message service (SMS) reminders coupled with a small monetary incentive conditioned on prompt vaccination have been shown to improve first-dose measles-containing vaccine (MCV1) uptake. We assessed whether SMS reminders and unconditional monetary incentives-more amenable to programmatic implementation-can improve MCV1 uptake in Kenya. METHODS: Caregivers of eligible infants aged 6-8 months were enrolled into an individually randomised controlled trial and assigned to receive either: no intervention (control), two SMS reminders (SMS) sent 3 days, and 1 day before the scheduled MCV1 date, or SMS reminders coupled with a Kenya Shilling (KES) 150 incentive (SMS +150 KES) sent 3 days before the scheduled MCV1 date. Study staff conducted a household follow-up visit at age 12 months to ascertain vaccination status. Log-binomial regression was used to estimate the relative and absolute difference in MCV1 timely coverage (by age 10 months), the primary outcome. RESULTS: Between 6 December 2016 and 31 March 2017, 179 infants were enrolled into each of the three study arms. Follow-up visits were completed between 19 April 2017 and 8 October 2017 for control (n=170), SMS (n=157) and SMS + 150 KES (n=158) children. MCV1 timely coverage was 68% among control arm infants compared with 78% in each intervention arm. This represented a non-statistically significant increase in the SMS arm (adjusted relative risk 1.13; 95% CI 0.99 to 1.30; p=0.070; adjusted risk difference 9.2%; 95% CI: -0.6 to 19.0%; p=0.066), but a statistically significant increase in the SMS + 150 KES arm (1.16; 95% CI 1.01 to 1.32; p=0.035; 10.6%; 95% CI 0.8 to 20.3%; p=0.034). CONCLUSION: These findings suggest that the effect of SMS reminders coupled with a small unconditional monetary incentive on MCV1 uptake is comparable to that of SMS reminders alone, limiting their utility. Further studies in the absence of unexpected supply-side constraints are needed. TRIAL REGISTRATION NUMBER: NCT02904642.

Adjustments for oral fluid quality and collection methods improve prediction of circulating tetanus antitoxin: Approaches for correcting antibody concentrations detected in a non-invasive specimen.

OBJECTIVES: To examine whether anti-tetanus toxoid (anti-TT) immunoglobulin G (IgG) levels measured in oral fluid and adjusted for collection difficulties and specimen quality are associated with total IgG and anti-TTIgG in oral fluid and assess if statistical adjustment for them improves prediction of anti-TT IgG in serum. METHODS: 267 children, ages 12 to 15 months, enrolled in the M-SIMU randomized controlled trial participated in this nested cross-sectional analysis. Venous blood and oral fluid (OF) specimens were collected, and OF collection difficulties such as crying or gagging were recorded. OF volume was documented and total IgG was measured in OF specimens and anti-TT IgG was measured in OF and serum by enzyme immunoassay (EIA). Collection difficulties, volume and sociodemographic characteristics were assessed in relation to total IgG and anti-TT IgG in OF via multivariate regression. These models were extended to evaluate the association between anti-TT IgG in OF and in serum. A prediction model was developed to adjust anti-TT IgG in OF estimates as proxy for serum. RESULTS: Blood in the specimen, sores in the mouth and crying were positively associated with total IgG concentration while high oral fluid volume and sucking on the swab were inversely associated. None were significant predictors of anti-TT IgG in OF after adjusting for total IgG (geometric mean [GM] ratio: 1.99; 95% confidence interval: 1.78-2.24) and vaccination history (GM ratio: 2.44; 95% CI: 1.98-3.01). When predicting anti-TT IgG levels in serum with OF, total IgG modified the effect of anti-TT IgG in OF. CONCLUSIONS: Anti-TT IgG in OF is a good proxy for levels in serum, after controlling for total IgG in the specimen and other variables. Post hoc adjustments for OF volume and total IgG concentration are an important consideration when conducting serosurveys with oral fluid.

Critical appraisal of a mHealth-assisted community-based cardiovascular disease risk screening program in rural Kenya: an operational research study.

Community health workers (CHWs) can participate in the cascade of hypertension and diabetes management in low and middle-income countries (LMICs). Their services may be enhanced with mobile health (mHealth) tools. In this operational research study, we describe the AFYACHAT mHealth-assisted cardiovascular health screening program in rural Kenya. In this study, A CHW screened a convenience sample of adults ≥ 40 years old in rural Kenya for cardiovascular disease (CVD) risk using the two-way AFYACHAT mHealth instrument. AFYACHAT analyzes a patient's age, sex, smoking, diabetes and systolic blood pressure and provides a four-tiered 10-year CVD risk score. User acceptability was assessed by an end-of-study interview with the CWH. Automated error logs were analyzed. Patient satisfaction was measured with a six-question satisfaction questionnaire. Screened participants with high CVD risk were followed-up via telephone to explore any actions taken following screening. In 24 months, one CHW screened 1650 participants using AFYACHAT. The 10-year risk of CVD was <10% for 1611 (98%) patients, 10 to <20% for 26 (1.6%), 20 to <30% in 12 (0.7%), and ≥30% for 1 (0.1%). The point prevalence of hypertension and diabetes was 27% and 1.9%, respectively. Seventy-five percent of participants with elevated CVD risk sought further medical care. There was high acceptability, a 15% miscode error rate, and high participant satisfaction with the screening program. Our operational research outlines how AFYACHAT mHealth tool can assist CHW perform rapid CVD screening; this provides a model framework for non-communicable disease screening in LMICs.

Can HIV recent infection surveillance help us better understand where primary prevention efforts should be targeted? Results of three pilots integrating a recent infection testing algorithm into routine programme activities in Kenya and Zimbabwe.

INTRODUCTION: Surveillance of recent HIV infections in national testing services has the potential to inform primary prevention programming activities. Focusing on procedures required to accurately determine recent infection, and the potential for recent infection surveillance to inform prevention efforts, we present the results of three independent but linked pilots of recency testing. METHODS: To distinguish recently acquired HIV infection from long-standing infection, in 2018 we applied a Recent Infection Testing Algorithm that combined a laboratory-based Limiting Antigen Avidity Enzyme Immunoassay with clinical information (viral-load; history of prior HIV diagnosis; antiretroviral therapy-exposure). We explored potential misclassification of test results and analysed the characteristics of participants with recent infection. We applied the algorithm in antenatal clinics providing prevention of mother-to-child transmission services in Siaya County, Kenya, outreach sites serving female sex workers in Zimbabwe, and routine HIV testing and counselling facilities in Nairobi, Kenya. In Nairobi, we also conducted recency testing among partners of HIV-positive participants. RESULTS: In Siaya County, 2.3% (10/426) of HIV-positive pregnant women were classified as recent. A risk factor analysis comparing women testing recent with those testing HIV-negative found women in their first trimester were significantly more likely to test recent than those in their second or third trimester. In Zimbabwe, 10.5% (33/313) of female sex workers testing HIV-positive through the outreach programme were classified recent. A risk factor analysis of women testing recent versus those testing HIV-negative, found no strong evidence of an association with recent infection. In Nairobi, among 532 HIV-positive women and men, 8.6% (46) were classified recent. Among partners of participants, almost a quarter of those who tested HIV-positive were classified as recent (23.8%; 5/21). In all three settings, the inclusion of clinical information helped improve the positive predictive value of recent infection testing by removing cases that were likely misclassified. CONCLUSIONS: We successfully identified recently acquired infections among persons testing HIV-positive in routine testing settings and highlight the importance of incorporating additional information to accurately classify recent infection. We identified a number of groups with a significantly higher proportion of recent infection, suggesting recent infection surveillance, when rolled-out nationally, may help in further targeting primary prevention efforts.

Is maternal HIV infection a risk factor for delayed or missed infant measles vaccination in western Kenya?

Measles is a highly infectious virus and one of the leading causes of childhood morbidity and mortality in areas with low immunization rates. Despite the introduction of the measles vaccine preventing about 20 million deaths between 2000 and 2016, there still is a low uptake of the vaccine, especially in low-income countries. Maternal HIV positive status is identified as one of the factors inhibiting the uptake of the measles vaccine in some settings. Using data from a Health and Demographic surveillance system (HDSS), and a Longitudinal Bio-behavioural Survey (LBBS), we assessed the effect of a mother's HIV status on a child's overall uptake of measles vaccine and timeliness in western Kenya. The findings did not show association between a mother's HIV status and a child's receipt of measles vaccine (OR = 0.84, 95% CI: 0.65, 1.08). However, higher socio-economic status (SES) was a positive factor for receipt of timely measles vaccine (OR = 1.34, 95% CI: 1.03, 1.75) for middle, (OR = 1.43, 95% CI: 1.10, 1.86) upper middle, and (OR = 1.51, 95% CI: 1.15, 1.98) higher quintiles as compared to the lower. Consequently, it is imperative to incorporate interventions that target low SES children and those that improve economic status.

Text Message Reminders and Unconditional Monetary Incentives to Improve Measles Vaccination in Western Kenya: Study Protocol for the Mobile and Scalable Innovations for Measles Immunization Randomized Controlled Trial.

BACKGROUND: Globally, 21 million children do not receive the measles vaccine each year. With high levels of mobile phone access and ownership, opportunities exist to leverage mobile health technologies to generate demand for immunization. OBJECTIVE: The aim of the Mobile and Scalable Innovations for Measles Immunization trial is to determine if text message (short message service, SMS) reminders, either with or without mobile phone-based incentives, can improve measles immunization coverage and timeliness in rural western Kenya. METHODS: This is a 3-arm, parallel, randomized controlled trial (RCT). Using simple randomization, caregivers in Siaya County, Kenya, will be randomized and evenly allocated to 1 of 3 study arms: (1) control, (2) SMS reminders only, and (3) SMS reminders plus a 150 Kenyan Shilling (KES) incentive. Participants assigned to the SMS group will be sent SMS reminders 3 days before and on the day before the measles immunization visit scheduled for when the child is 9 months of age. Participants in the incentive arm will, in addition to SMS reminders as above, be sent an unconditional 150 KES mobile-money incentive to their mobile phone 3 days before the child becomes 9 months of age. Children will be followed up to the age of 12 months to assess the primary outcome, a measles vaccination by 10 months of age. Log-binomial regressions will be used to calculate relative risks. RESULTS: Enrollment was completed in March 2017. We enrolled 537 caregivers and their infants into the following groups: control (n=179), SMS reminders only (n=179), and SMS reminders plus 150 KES (n=179). Results will be made publicly available in 2020. CONCLUSIONS: Few RCTs have examined the effect of text message reminders to improve measles immunization coverage. This is the first study to assess the effect of SMS reminders with and without unconditionally provided mobile-money incentives to improve measles immunization coverage. TRIAL REGISTRATION: ClinicalTrials.gov NCT02904642; https://clinicaltrials.gov/ct2/show/NCT02904642 (Archived by WebCite® at http://www.webcitation.org/78r7AzD2X). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/13221.

Community-based screening for cardiovascular risk using a novel mHealth tool in rural Kenya.

BACKGROUND: An increasing burden of cardiovascular disease (CVD) in low-resource settings demands innovative public health approaches. OBJECTIVES: To design and test a novel mHealth tool for use by community health workers (CHWs) to identify individuals at high CVD risk who would benefit from education and/or pharmacologic interventions. METHODS: We designed and implemented a novel two-way mobile phone application, "AFYACHAT," to rapidly screen for CVD risk in rural Kenya. AFYACHAT collects and stores SMS text message data entered by a CHW on a subject's age, sex, smoking, diabetes, and systolic blood pressure, and returns as SMS text message the category of 10-year CVD risk: "GREEN" (<10% 10 year risk of cardiovascular event), "YELLOW" (10 to <20%), "orange"(20 to <30%), or "RED" (≥30%). CHWs were equipped and trained to use an automated blood pressure device and the mHealth tool. RESULTS: Five CHWs screened 2,865 subjects in remote rural communities in Kenya over a 22 month period (2015-17). The median age of subjects was 50 (IQR 43 to 60) and 1581 (55%) were female. Point prevalence of hypertension (systolic blood pressure>140mmHg), diabetes, and tobacco use were 23%, 3.2%, and 22%, respectively. Overall, the 10-year risk of CVD among patients was <10% in 2778 (97%) patients, 10 to <20% in 65 (2.3%), 20 to <30% in 12 (0.4%), and ≥30% in 10 (0.2%). CONCLUSION: We have developed a mHealth tool that can be used by CHWs to screen for CVD risk factors, demonstrating proof-of-concept in rural Kenya.

Mobile phone-delivered reminders and incentives to improve childhood immunisation coverage and timeliness in Kenya (M-SIMU): a cluster randomised controlled trial.

BACKGROUND: As mobile phone access continues to expand globally, opportunities exist to leverage these technologies to support demand for immunisation services and improve vaccine coverage. We aimed to assess whether short message service (SMS) reminders and monetary incentives can improve immunisation uptake in Kenya. METHODS: In this cluster-randomised controlled trial, villages were randomly and evenly allocated to four groups: control, SMS only, SMS plus a 75 Kenya Shilling (KES) incentive, and SMS plus 200 KES (85 KES = USD$1). Caregivers were eligible if they had a child younger than 5 weeks who had not yet received a first dose of pentavalent vaccine. Participants in the intervention groups received SMS reminders before scheduled pentavalent and measles immunisation visits. Participants in incentive groups, additionally, received money if their child was timely immunised (immunisation within 2 weeks of the due date). Caregivers and interviewers were not masked. The proportion of fully immunised children (receiving BCG, three doses of polio vaccine, three doses of pentavalent vaccine, and measles vaccine) by 12 months of age constituted the primary outcome and was analysed with log-binomial regression and General Estimating Equations to account for correlation within clusters. This trial is registered with ClinicalTrials.gov, number NCT01878435. FINDINGS: Between Oct 14, 2013, and Oct 17, 2014, we enrolled 2018 caregivers and their infants from 152 villages into the following four groups: control (n=489), SMS only (n=476), SMS plus 75 KES (n=562), and SMS plus 200 KES (n=491). Overall, 1375 (86%) of 1600 children who were successfully followed up achieved the primary outcome, full immunisation by 12 months of age (296 [82%] of 360 control participants, 332 [86%] of 388 SMS only participants, 383 [86%] of 446 SMS plus 75 KES participants, and 364 [90%] of 406 SMS plus 200 KES participants). Children in the SMS plus 200 KES group were significantly more likely to achieve full immunisation at 12 months of age (relative risk 1·09, 95% CI 1·02-1·16, p=0·014) than children in the control group. INTERPRETATION: In a setting with high baseline immunisation coverage levels, SMS reminders coupled with incentives significantly improved immunisation coverage and timeliness. Given that global immunisation coverage levels have stagnated around 85%, the use of incentives might be one option to reach the remaining 15%. FUNDING: Bill & Melinda Gates Foundation.

The Mobile Solutions for Immunization (M-SIMU) Trial: A Protocol for a Cluster Randomized Controlled Trial That Assesses the Impact of Mobile Phone Delivered Reminders and Travel Subsidies to Improve Childhood Immunization Coverage Rates and Timeliness in Western Kenya.

BACKGROUND: Text message (short message service, SMS) reminders and incentives are two demand-side interventions that have been shown to improve health care-seeking behaviors by targeting participant characteristics such as forgetfulness, lack of knowledge, and transport costs. Applying these interventions to routine pediatric immunizations may improve vaccination coverage and timeliness. OBJECTIVE: The Mobile Solutions for Immunization (M-SIMU) trial aims to determine if text message reminders, either with or without mobile phone-based incentives, sent to infant's parents can improve immunization coverage and timeliness of routine pediatric vaccines in rural western Kenya. METHODS: This is a four-arm, cluster, randomized controlled trial. Villages are randomized to one of four study arms prior to enrollment of participants. The study arms are: (1) no intervention (a general health-related text message will be texted to this group at the time of enrollment), (2) text message reminders only, (3) text message reminders and a 75 Kenyan Shilling (KES) incentive, or (4) text message reminders and a KES200 incentive. Participants assigned to study arms 2-4 will receive two text message reminders; sent 3 days before and one day before the scheduled immunization visit at 6, 10, and 14 weeks for polio and pentavalent (containing diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenza type b antigens) type b antigens) vaccines, and at 9 months for measles vaccine. Participants in incentive arms will, in addition to text message reminders as above, receive mobile phone-based incentives after each timely vaccination, where timely is defined as vaccination within 2 weeks of the scheduled date for each of the four routine expanded program immunization (EPI) vaccination visits. Mother-infant pairs will be followed to 12 months of age where the primary outcome, a fully immunized child, will be ascertained. A fully immunized child is defined as a child receiving vaccines for bacille Calmette-Guerin, three doses of pentavalent and polio, and measles by 12 months of age. General estimating equation (GEE) models that account for clustering will be employed for primary outcome analyses. RESULTS: Enrollment was completed in October 2014. Twelve month follow-up visits to ascertain immunization status from the maternal and child health booklet were completed in February 2016. CONCLUSIONS: This is one of the first studies to examine the effect of text message reminders on immunization coverage and timeliness in a lower income country and is the first study to assess the effect of mobile money-based incentives to improve immunization coverage. TRIAL REGISTRATION: Clinicaltrials.gov NCT01878435; https://clinicaltrials.gov/ct2/show/NCT01878435 (Archived by WebCite at http://www.webcitation.org/6hQlwGYJR).

Individual level determinants for not receiving immunization, receiving immunization with delay, and being severely underimmunized among rural western Kenyan children.

BACKGROUND: Estimating vaccination coverage and delays are important because these measures can identify at risk sub-populations who can be targeted with interventions and public health policies. This paper sought to determine estimates and risk factors for children in rural western Kenya who did not receive immunization, received immunization with delay, or were severely underimmunized. METHODS: Caregivers of children aged 12-23 months old were surveyed for immunization history using written records from the immunization booklet. Risk factors for not receiving immunization, delayed immunization, and severe underimmunization were calculated using log-binomial regression. Children were categorized as delayed if a given immunization was received greater than four weeks from the age-appropriate scheduled date. Severely underimmunized children were those who were fully unvaccinated for more than 90 days and had three or more vaccines delayed or not given. RESULTS: Immunization coverage for pentavalent1, pentavalent3, measles, and fully immunized child (FIC; BCG, three doses of polio, three doses of pentavalent, and measles vaccines) were 99%, 94%, 83%, and 80%, respectively. Approximately, 10%, 24%, and 29%, of children were delayed for pentavalent1, pentavalent3, and measles, respectively. Each model produced a unique combination of risk factors with only advanced maternal age as a risk factor common to all models. Children with delayed receipt of pentavalent1 were at risk for not receiving pentavalent3 (RR: 5.20; 95%CI 3.48, 7.77), measles vaccine (RR: 1.48; 95%CI 1.12, 1.95), and not achieving FIC (RR: 1.88; 95%CI 1.51, 2.34) compared with children who received pentavalent1 on time. CONCLUSIONS: Immunization coverage among 12-23 month old children was high, yet a substantial proportion of children were vaccinated with delay. Although vaccine coverage and timeliness are often conceptualized as separate measures, the finding that delayed pentavalent1 receipt was a strong risk factor for not receiving future immunizations indicates the two measures are intertwined.