Walekhwa et al. BMC Infectious Diseases (2021) 21:596 https://doi.org/10.1186/s12879-021-06213-5 RESEARCH Open Access Measles outbreak in Western Uganda: a case-control study Abel Wilson Walekhwa1*, Moses Ntaro1, Peter Chris Kawungezi1, Chiara Achangwa2, Rabbison Muhindo1, Emmanuel Baguma1, Michael Matte1, Richard Migisha3, Raquel Reyes4, Peyton Thompson5, Ross M. Boyce1,6 and Edgar M. Mulogo1 Abstract Background: Measles outbreaks are prevalent throughout sub-Saharan Africa despite the preventive measures like vaccination that target under five-year-old children and health systems strengthening efforts like prioritizing the supply chain for supplies. Measles immunization coverage for Kasese district and Bugoye HC III in 2018 was 72 and 69%, respectively. This coverage has been very low and always marked red in the Red categorization (below the national target/poor performing) on the national league table indicators. The aim of this study was to assess the scope of the 2018–2019 measles outbreak and the associated risk factors among children aged 0–60 months in Bugoye sub-county, Kasese district, western Uganda. Methods: We conducted a retrospective unmatched case-control study among children aged 0–60 months with measles (cases) who had either a clinical presentation or a laboratory confirmation (IgM positivity) presenting at Bugoye Health Centre III (BHC) or in the surrounding communities between December 2018 and October 2019.. Caregivers of the controls (whose children did not have measles) were selected at the time of data collection in July 2020. A modified CDC case investigation form was used in data collection. Quantitative data was collected and analyzed using Microsoft excel and STATA version 13. The children’s immunization cards and health registers at BHC were reviewed to ascertain the immunization status of the children before the outbreak. Results: An extended measles outbreak occurred in Bugoye, Uganda occured between December 2018 and October 2019. All 34 facility-based measles cases were documented to have had maculopapular rash, conjunctivitis, and cough. Also, the majority had fever (97%), coryza (94.1%), lymphadenopathy (76.5%), arthralgias (73.5%) and Koplik Spots (91.2%) as documented in the clinical registers. Similar symptoms were reported among 36 community-based cases. Getting infected even after immunized, low measles vaccination coverage were identified as the principal risk factors for this outbreak. Conclusion: Measles is still a significant problem. This study showed that this outbreak was associated with under- vaccination. Implementing a second routine dose of measles-rubella vaccine would not only increase the number of children with at least one dose but also boost the immunity of those who had the first dose. Keywords: Measles, Outbreak, Immunization, Epidemiology, Uganda * Correspondence: [email protected] 1Department of Community Health, Faculty of Medicine, Mbarara University of Science & Technology, P.O. BOX 1410, Mbarara, Uganda Full list of author information is available at the end of the article © The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Walekhwa et al. BMC Infectious Diseases (2021) 21:596 Page 2 of 9 Background Therefore, the objective of this study was to investigate Measles is a highly infectious disease caused by the mea- the scope of and the demographic, clinical, and geo- sles virus, which has an attack rate greater than 90% graphic risk factors associated with the 2018–2019 mea- among susceptible persons [1]. Classic symptoms in- sles outbreak in Bugoye subcounty.. Specifically, we clude fever, cough, coryza, conjunctivitis, and maculo- focused on children aged 0–59 months, given the higher papular rash. The rash appears as red spots on the skin, risk of complications and mortality. Our goal was to in- typically 3 to 5 days after the development of other form policymakers, including District Councilors and symptoms [2, 3]. Complications of the disease, which in- sub-county leadership, of the risk factors associated with clude ear infections, pneumonia, and encephalitis, are measles outbreaks in order to influence resource alloca- common and can be fatal, especially in malnourished or tion and guide potential interventions at the District immune compromised children [4]. Health Office level. With an almost 300% increase in cases reported be- tween 2016 and 2018, measles continues to represent Methods a significant public health challenge in sub-Saharan Study setting Africa [5]. Estimates suggest that upwards of 14 mil- The study was conducted in Bugoye sub-county, Kasese lion children under five years of age live in “cold district in Southwestern Uganda (Fig. 1). The sub-county spots,” defined as highly endemic/high danger areas, was selected following reports of measles cases presenting across the region, and 8–12 million children remain to local health centres. Bugoye spans a rural, highland area unvaccinated [6]. In 2018 alone, models suggested of approximately 55 km2, which is characterized by deep that measles affected nearly ten million children and river valleys and steep hillsides with elevations up to 2000 resulted in 140,000 deaths globally [7]; the African re- m. The sub-county is comprised of five parishes and gion was among the most impacted regions with 1, thirty-five villages with a population of approximately 50, 759,000 total cases and 52,600 deaths [8]. Unfortu- 000, one-quarter of whom are children under 5 years of nately, recent trends continue to show increases in all age [17]. The main economic activity is agriculture with regions [5]. This increase was particularly pronounced most households engaged in subsistence farming. in the WHO Africa Region, which recorded a 700% There are eight health facilities in the sub-county in- increase over the first four months of 2019 [9], cluding six level II and two level III health centres, one highlighting that measles outbreaks remain a major of which is a private, not- for- profit facility. Bugoye public health challenge. Level III Health Centre (BHC) is the only public level III In Uganda specifically, the measles situation has health facility in the sub-county. Level III Health Centres remained relatively stagnant. For example, in 2018, 46 are staffed by a senior clinical officer, a clinical officer, districts reported measles outbreaks [10, 11]. The laboratory technicians, health assistants, nurses, and current Uganda National Expanded Program on midwives. Available services include routine antenatal Immunization (UNEPI) schedule recommends a single care, an immunization clinic, a general outpatient clinic, measles vaccination (MCV) at nine months of age an antiretroviral clinic for patients with HIV, and small [12]. This is in contrast to WHO recommendations, inpatient and maternity wards. Level II health centres which suggest that reaching all children with two provide immunization services, antenatal care, and out- doses of measles vaccine should be the standard for patient clinics, but do not offer inpatient services or HIV all national immunization programs [13]. Further- care. The health facilities offer immunizations services more, the WHO states that in countries with ongoing through two models; static (facility based) during week transmission in which the risk of measles mortality days (Monday to Friday) then outreaches (community remains high, the first dose (MCV1) should be given based) that are organized one per month. Current at nine months of age and a second dose should be Ugandan immunization guidelines recommend measles given between 15 and 18 months of age [14, 15]. immunization with a single dose at the age of nine From December 2018 through October of 2019, months [18]. Bugoye Health Centre III (BHC), located in Kasese Dis- trict of southwestern Uganda, reported a large number of suspect measles cases. Eight clinical samples were Study design submitted to the Uganda Virus Research Institute Case-Control investigation (UVRI) for serological testing. Five of these samples were For the purposes of the investigation, WHO measles confirmed (i.e. IgM positive) and the clinical staff were case definitions of both suspected and confirmed were subsequently instructed to use clinical diagnosis for any used [19]. Facility-based cases were defined as children additional cases. All cases were documented pending less than or equal to five years of age who met the fol- further investigation according to BHC records [16]. lowing criteria: Walekhwa et al. BMC Infectious Diseases (2021) 21:596 Page 3 of 9 Fig. 1 Map of Bugoye Subcounty, Kasese District (1) We defined a suspected case as fever language (Lukonzo). The latitude and longitude of partici- (temperature ≥ 37.5 °C) and generalized skin rash pating households were recorded using a GPS application lasting for three or more days with at least one of installed on mobile phones. Child immunization cards the following: cough, coryza and conjuctivitis in any under possession of the caregivers and health registers at child aged 0–60 months presenting at Bugoye facilities were reviewed to verify immunization of partici- health centre, or residing in Bugoye Sub-county be- pating children before the outbreak occurred.