Comparing performance of year-round and campaign-mode influenza vaccination strategies among children aged 6-23 months in Kenya: 2019-2021.

INTRODUCTION: In 2016, the Kenya National Immunization Technical Advisory Group requested additional programmatic and cost effectiveness data to inform the choice of strategy for a national influenza vaccination program among children aged 6-23 months of age. In response, we conducted an influenza vaccine demonstration project to compare the performance of a year-round versus campaign-mode vaccination strategy. Findings from this demonstration project will help identify essential learning lessons for a national program. METHODS: We compared two vaccine delivery strategies: (i) a year-round vaccination strategy where influenza vaccines were administered throughout the year at health facilities. This strategy was implemented in Njoro sub-county in Nakuru (November 2019 to October 2021) and Jomvu sub-county in Mombasa (December 2019 to October 2021), (ii) a campaign-mode vaccination strategy where vaccines were available at health facilities over four months. This strategy was implemented in Nakuru North sub-county in Nakuru (June to September 2021) and Likoni sub-county in Mombasa (July to October 2021). We assessed differences in coverage, dropout rates, vaccine wastage, and operational needs. RESULTS: We observed similar performance between strategies in coverage of the first dose of influenza vaccine (year-round strategy 59.7 %, campaign strategy 63.2 %). The coverage obtained in the year-round sub-counties was similar (Njoro 57.4 %; Jomvu 63.1 %); however, more marked differences between campaign sub-counties were observed (Nakuru North 73.4 %; Likoni 55.2 %). The campaign-mode strategy exceeded the cold chain capacity of participating health facilities, requiring thrice monthly instead of once monthly deliveries, and was associated with a two-fold increase in workload compared to the year-round strategy (168 vaccines administered per day in the campaign strategy versus 83 vaccines administered per day in the year-round strategy). CONCLUSION: Although both strategies had similar coverage levels, the campaign-mode strategy was associated with considerable operational needs that could significantly impact the immunization program.

HPV vaccination in Kenya: a study protocol to assess stakeholders' perspectives on implementation drivers of HPV vaccination and the acceptability of the reduced dose strategy among providers.

Background: Cervical cancer is the leading cause of cancer-related deaths among Kenyan women. Persistent infection with high-risk oncogenic Human papillomavirus (HPV) genotypes is a necessary cause of cervical cancer. HPV vaccines are safe, durable, and efficacious in preventing incident HPV infections. In Kenya, despite efforts to increase HPV vaccination, coverage remains low. We sought to assess: (1) barriers and facilitators of HPV vaccination from the perspective of adolescent girls and young women (AGYW), their guardians as well as stakeholders involved in HPV vaccine delivery, and (2) the acceptability of the single dose of the HPV vaccination among healthcare providers (HCPs). Methods: Our study is nested within the KENya Single-dose HPV-vaccine Efficacy study (KEN SHE) that sought to test the efficacy of single-dose bivalent (HPV 16/18) and single-dose nonavalent (HPV 16/18/31/33/45/52/58/6/11) vaccination. We are conducting this study in Kiambu, Nairobi, and Kisumu counties. In these counties, we are interviewing stakeholders (n = ∼25), selected based on their role in HPV vaccination at the county and national levels. Interviews are audio recorded and conducted in English or Swahili. The semi-structured interview guides were designed based on: (1) the Theoretical Domains Framework (TDF) for AGYW and guardians and (2) the Consolidated Framework for Implementation Research (CFIR) for other stakeholders. The Theoretical Framework of Acceptability (TFA) was leveraged to design the survey administered to HCPs (n = ∼309) involved in HPV vaccination. We will develop a codebook based on emerging codes from the transcripts and constructs from the TDF and CFIR. Emerging themes will be summarized highlighting similarities and differences between and within the different stakeholder groups and counties. Descriptive statistics and a χ2 test will be used to assess the distribution of responses between the different sites and regression analysis will be used to assess factors associated with high acceptability of the single-dose strategy while controlling for confounding variables. Discussion: Our study will describe key barriers and facilitators that affect HPV vaccination from the perspective of multiple stakeholders as well as insights on the perspective of HCPs towards the single-dose strategy to inform the designing of strategies to increase HPV vaccination uptake in Kenya and comparable settings.

Impact, cost-effectiveness, and budget implications of HPV vaccination in Kenya: A modelling study.

BACKGROUND: Sub-Saharan Africa has the highest rate of cervical cancer cases and deaths worldwide. Kenya introduced a quadrivalent HPV vaccine (GARDASIL, hereafter referred to as GARDASIL-4) for ten-year-old girls in late 2019 with donor support from Gavi, the Vaccine Alliance. As Kenya may soon graduate from Gavi support, it is important to evaluate the potential cost-effectiveness and budget impact of the current HPV vaccine, and potential alternatives. METHODS: We used a proportionate outcomes static cohort model to evaluate the annual budget impact and lifetime cost-effectiveness of vaccinating ten-year-old girls over the period 2020-2029. We included a catch-up campaign for girls aged 11-14 years in 2020. We estimated cervical cancer cases, deaths, disability adjusted life years (DALYs), and healthcare costs (government and societal perspective) expected to occur with and without vaccination over the lifetimes of each cohort of vaccinated girls. For each of the four products available globally (CECOLIN©, CERVARIX©, GARDASIL-4©, and GARDASIL-9 ©), we estimated the cost (2021 US$) per DALY averted compared to no vaccine and to each other. Model inputs were obtained from published sources, as well as local stakeholders. RESULTS: We estimated 320,000 cases and 225,000 deaths attributed to cervical cancer over the lifetimes of the 14 evaluated birth cohorts. HPV vaccination could reduce this burden by 42-60 %. Without cross-protection, CECOLIN had the lowest net cost and most attractive cost-effectiveness. With cross-protection, CERVARIX was the most cost-effective. Under either scenario the most cost-effective vaccine had a 100 % probability of being cost-effective at a willingness-to-pay threshold of US$ 100 (5 % of Kenya's national gross domestic product per capita) compared to no vaccination. Should Kenya reach its target of 90 % coverage and graduate from Gavi support, the undiscounted annual vaccine program cost could exceed US$ 10 million per year. For all three vaccines currently supported by Gavi, a single-dose strategy would be cost-saving compared to no vaccination. CONCLUSION: HPV vaccination for girls is highly cost-effective in Kenya. Compared to GARDASIL-4, alternative products could provide similar or greater health benefits at lower net costs. Substantial government funding will be required to reach and sustain coverage targets as Kenya graduates from Gavi support. A single dose strategy is likely to have similar benefits for less cost.