Katherine Kirkby

Ms. Katherine Kirkby

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 June 2023 in International Journal of Epidemiology
Verified
Journal Article
Open access
PDF file
KKKatherine Kirkby
Katherine Kirkby
Nicole BergenNicole Bergen
Nicole Bergen
ABAndreia Baptista
Andreia Baptista
ASAnne Schlotheuber
Anne Schlotheuber
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
Disaggregated health data are a central requirement for health inequality monitoring, which is the process of quantifying and assessing health inequalities in a defined population. These data, which show how health varies across population subgroups, help with the identification of situations of health inequity, where there are preventable and unfair differences in health, wellbeing, and access to quality health services. Sustainably addressing health inequities is part of major global health and development initiatives, including the United Nations 2030 Agenda for Sustainable Development.

21 June 2022 in Vaccines
Verified
Journal Article
Open access
PDF file
NJNicole E Johns
Nicole E Johns
TSThiago M Santos
Thiago M Santos
LALuisa Arroyave
Luisa Arroyave
BCBianca O Cata-Preta
Bianca O Cata-Preta
SHShirin Heidari
Shirin Heidari
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
Gender-related barriers to immunization are key targets to improve immunization coverage and equity. We used individual-level demographic and health survey data from 52 low- and middle-income countries to examine the relationship between women’s social independence (measured by the Survey-based Women’s emPowERment (SWPER) Global Index) and childhood immunization. The primary outcome was receipt of three doses of the diphtheria-tetanus-pertussis vaccine (DTP3) among children aged 12–35 months; we secondarily examined failure to receive any doses of DTP-containing vaccines. We summarized immunization coverage indicators by social independence tertile and estimated crude and adjusted summary measures of absolute and relative inequality. We conducted all analyses at the country level using individual data; median results across the 52 examined countries are also presented. In crude comparisons, median DTP3 coverage was 12.3 (95% CI 7.9; 16.3) percentage points higher among children of women with the highest social independence compared with children of women with the lowest. Thirty countries (58%) had a difference in coverage between those with the highest and lowest social independence of at least 10 percentage points. In adjusted models, the median coverage was 7.4 (95% CI 5.0; 9.1) percentage points higher among children of women with the highest social independence. Most countries (41, 79%) had statistically significant relative inequality in DTP3 coverage by social independence. The findings suggest that greater social independence for women was associated with better childhood immunization outcomes, adding evidence in support of gender-transformative strategies to reduce childhood immunization inequities.

25 July 2022 in BMJ Open
Verified
Journal Article
Open access
PDF file
NJNicole E Johns
Nicole E Johns
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
MCMike Chisema
Mike Chisema
M. Carolina DanovaroM. Carolina Danovaro
M. Carolina Danovaro
KKKatherine Kirkby
Katherine Kirkby
BZBoston Zimba
Boston Zimba
Objectives Despite significant progress in childhood vaccination coverage globally, substantial inequality remains. Remote rural populations are recognised as a priority group for immunisation service equity. We aimed to link facility and individual data to examine the relationship between distance to services and immunisation coverage empirically, specifically using a rural population. Design and setting Retrospective cross-sectional analysis of facility data from the 2013–2014 Malawi Service Provision Assessment and individual data from the 2015–2016 Malawi Demographic and Health Survey, linking children to facilities within a 5 km radius. We examined associations between proximity to health facilities and vaccination receipt via bivariate comparisons and logistic regression models. Participants 2740 children aged 12–23 months living in rural areas. Outcome measures Immunisation coverage for the six vaccines included in the Malawi Expanded Programme on Immunization schedule for children under 1 year at time of study, as well as two composite vaccination indicators (receipt of basic vaccines and receipt of all recommended vaccines), zero-dose pentavalent coverage, and pentavalent dropout. Findings 72% (706/977) of facilities offered childhood vaccination services. Among children in rural areas, 61% were proximal to (within 5 km of) a vaccine-providing facility. Proximity to a vaccine-providing health facility was associated with increased likelihood of having received the rotavirus vaccine (93% vs 88%, p=0.004) and measles vaccine (93% vs 89%, p=0.01) in bivariate tests. In adjusted comparisons, how close a child was to a health facility remained meaningfully associated with how likely they were to have received rotavirus vaccine (adjusted OR (AOR) 1.63, 95% CI 1.13 to 2.33) and measles vaccine (AOR 1.62, 95% CI 1.11 to 2.37). Conclusion Proximity to health facilities was significantly associated with likelihood of receipt for some, but not all, vaccines. Our findings reiterate the vulnerability of children residing far from static vaccination services; efforts that specifically target remote rural populations living far from health facilities are warranted to ensure equitable vaccination coverage.

18 November 2022 in Vaccines
Verified
Journal Article
Open access
PDF file
NJNicole E Johns
Nicole E Johns
KKKatherine Kirkby
Katherine Kirkby
TGTracey Susan Goodman
Tracey Susan Goodman
SHShirin Heidari
Shirin Heidari
JMJean Munro
Jean Munro
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
The role of gender inequality in childhood immunization is an emerging area of focus for global efforts to improve immunization coverage and equity. Recent studies have examined the relationship between gender inequality and childhood immunization at national as well as individual levels; we hypothesize that the demonstrated relationship between greater gender equality and higher immunization coverage will also be evident when examining subnational-level data. We thus conducted an ecological analysis examining the association between the Subnational Gender Development Index (SGDI) and two measures of immunization—zero-dose diphtheria-tetanus-pertussis (DTP) prevalence and 3-dose DTP coverage. Using data from 2010–2019 across 702 subnational regions within 57 countries, we assessed these relationships using fractional logistic regression models, as well as a series of analyses to account for the nested geographies of subnational regions within countries. Subnational regions were dichotomized to higher gender inequality (top quintile of SGDI) and lower gender inequality (lower four quintiles of SGDI). In adjusted models, we find that subnational regions with higher gender inequality (favoring men) are expected to have 5.8 percentage points greater zero-dose prevalence than regions with lower inequality [16.4% (95% confidence interval (CI) 14.5–18.4%) in higher-inequality regions versus 10.6% (95% CI 9.5–11.7%) in lower-inequality regions], and 8.2 percentage points lower DTP3 immunization coverage [71.0% (95% CI 68.3–73.7%) in higher-inequality regions versus 79.2% (95% CI 77.7–80.7%) in lower-inequality regions]. In models accounting for country-level clustering of gender inequality, the magnitude and strength of associations are reduced somewhat, but remain statistically significant in the hypothesized direction. In conjunction with published work demonstrating meaningful associations between greater gender equality and better childhood immunization outcomes in individual- and country-level analyses, these findings lend further strength to calls for efforts towards greater gender equality to improve childhood immunization and child health outcomes broadly.

29 March 2023 in Vaccines
Verified
Journal Article
Open access
PDF file
NJNicole E Johns
Nicole E Johns
BCBianca O Cata-Preta
Bianca O Cata-Preta
KKKatherine Kirkby
Katherine Kirkby
LALuisa Arroyave
Luisa Arroyave
Nicole BergenNicole Bergen
Nicole Bergen
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
Substantial progress in maternal and neonatal tetanus elimination has been made in the past 40 years, with dramatic reductions in neonatal tetanus incidence and mortality. However, twelve countries have still not achieved maternal and neonatal tetanus elimination, and many countries that have achieved elimination do not meet key sustainability thresholds to ensure long-lasting elimination. As maternal and neonatal tetanus is a vaccine-preventable disease (with coverage of the infant conferred by maternal immunization during and prior to pregnancy), maternal tetanus immunization coverage is a key metric for monitoring progress towards, equity in, and sustainability of tetanus elimination. In this study, we examine inequalities in tetanus protection at birth, a measure of maternal immunization coverage, across 76 countries and four dimensions of inequality via disaggregated data and summary measures of inequality. We find that substantial inequalities in coverage exist for wealth (with lower coverage among poorer wealth quintiles), maternal age (with lower coverage among younger mothers), maternal education (with lower coverage among less educated mothers), and place of residence (with lower coverage in rural areas). Inequalities existed for all dimensions across low- and lower-middle-income countries, and across maternal education and place of residence across upper-middle-income countries. Though global coverage changed little over the time period 2001–2020, this obscured substantial heterogeneity across countries. Notably, several countries had substantial increases in coverage accompanied by decreases in inequality, highlighting the need for equity considerations in maternal and neonatal tetanus elimination and sustainability efforts.

26 November 2024 in Vaccines
Verified
Journal Article
Open access
PDF file
KKKatherine Kirkby
Katherine Kirkby
DADaniel A. Antiporta
Daniel A. Antiporta
ASAnne Schlotheuber
Anne Schlotheuber
PMPatricia Menéndez
Patricia Menéndez
M. Carolina DanovaroM. Carolina Danovaro
M. Carolina Danovaro
Ahmad Reza HosseinpoorAhmad Reza Hosseinpoor
Ahmad Reza Hosseinpoor
Background: Monitoring immunization inequalities is crucial for achieving equity in vaccine coverage. Summary measures of health inequality provide a single numerical expression of immunization inequality. However, the impact of different summary measures on conclusions about immunization inequalities has not been thoroughly studied. Methods: We used disaggregated data from household surveys conducted in 92 low- and middle-income countries between 2013 and 2022. Inequality was assessed for two indicators of childhood immunization coverage [three doses of combined diphtheria, tetanus, and pertussis (DTP) vaccine and non-receipt of DTP vaccine or “zero-dose”] across three dimensions of inequality (place of residence, economic status, and subnational region). We calculated 16 summary measures of health inequality and compared the results. Results: These measures of inequality showed more similarities than differences, but the choice of measure can affect inequality assessment. Absolute and relative measures sometimes produced differing results, showing the importance of using both types of measures when assessing immunization inequality. Outliers influenced differences and ratios, but the effect of outlier estimates was moderated through the use of complex measures, which consider all subgroups and their population sizes. The choice of appropriate complex measure depends on the audience, interpretation, and outlier sensitivity. Conclusions: Summary measures are useful for assessing changes in inequality over time and making comparisons across different geographical areas and vaccines, but assumptions and value judgements made when selecting summary measures of inequality should be made explicit in research.