INTRODUCTION: Data about healthcare workers' (HCW) willingness to accept and recommend seasonal influenza vaccination in countries without influenza vaccination programs are limited. METHODS: We conducted a cross-sectional survey in 7 of the 47 counties in Kenya to examine HCW's knowledge and perceptions of seasonal influenza disease and vaccination. We aimed to enroll all HCW who deliver clinical services directly or peripherally to patients from 5 health facilities in each county. We used chi-square tests and mixed effects logistic regression to identify variables associated with HCW's willingness to accept and recommend seasonal influenza vaccination. RESULTS: From May-June 2018, we enrolled 2035 HCW, representing 49.0 % of targeted respondents from 35 facilities. Most HCW (82.1 %) were from public health facilities. Among the HCW who had heard of seasonal influenza, 87.3 % (1420/1627) believed it can cause severe illness. Most HCW (1076/1209; 89.0 %) were willing to receive a seasonal influenza vaccine if it was recommended for them and provided for free, and 91.4 % (1441/1576) would vaccinate or recommend vaccination to their patients if vaccine was available. Only 17.6 % (213/1212) reported having ever received a seasonal influenza vaccine. HCW who believed that influenza could cause severe illness (aOR 1.8; 95 % CI 1.0-3.2) and that people around them would be better protected from influenza illness if HCW are vaccinated (aOR 3.1; 95 % CI 2.0-4.9) were more likely to report willingness to accept vaccination. HCW from private health facilities (aOR 2.2; 95 % CI 1.3-6.4), and those who believed that people around them are better protected if HCW are vaccinated (aOR 3.5; 95 % CI 2.2-5.8) were more likely to report willingness to vaccinate or recommend vaccination to patients. CONCLUSION: Our findings suggest favorable attitudes among HCW towards seasonal influenza vaccination, many of whom are motivated by the desire to protect the health of others around them.

In Kenya, influenza virus circulates year-round, raising questions about optimum strategies for vaccination. Given national interest in introducing influenza vaccination for young children 6-23 months of age, we modeled total influenza-associated illnesses (inclusive of hospitalizations, outpatient illnesses, and non‒medically attended illnesses) averted by multiple potential vaccination strategies: year-round versus seasonal-campaign vaccination, and vaccination starting in April (Southern Hemisphere influenza vaccine availability) versus October (Northern Hemisphere availability). We modeled average vaccine effectiveness of 50% and annual vaccination coverage of 60%. In the introduction year, year-round vaccination averted 6,410 total illnesses when introduced in October and 7,202 illnesses when introduced in April, whereas seasonal-campaign vaccination averted 10,236 (October) to 11,612 (April) illnesses. In the year after introduction, both strategies averted comparable numbers of illnesses (10,831-10,868 for year-round, 10,175-11,282 for campaign). Campaign-style vaccination would likely have a greater effect during initial pediatric influenza vaccine introduction in Kenya; however, either strategy could achieve similar longer-term effects.

BACKGROUND: Respiratory syncytial virus (RSV) is one of the main causes of hospitalization for lower respiratory tract infection in children under five years of age globally. Maternal vaccines and monoclonal antibodies for RSV prevention among infants are approved for use in high income countries. However, data are limited on the economic burden of RSV disease from low- and middle-income countries (LMIC) to inform decision making on prioritization and introduction of such interventions. This study aimed to estimate household and health system costs associated with childhood RSV in Kenya. METHODS: A structured questionnaire was administered to caregivers of children aged < 5 years admitted to referral hospitals in Kilifi (coastal Kenya) and Siaya (western Kenya) with symptoms of acute lower respiratory tract infection (LRTI) during the 2019-2021 RSV seasons. These children had been enrolled in ongoing in-patient surveillance for respiratory viruses. Household expenditures on direct and indirect medical costs were collected 10 days prior to, during, and two weeks post hospitalization. Aggregated health system costs were acquired from the hospital administration and were included to calculate the cost per episode of hospitalized RSV illness. RESULTS: We enrolled a total of 241 and 184 participants from Kilifi and Siaya hospitals, respectively. Out of these, 79 (32.9%) in Kilifi and 21(11.4%) in Siaya, tested positive for RSV infection. The total (health system and household) mean costs per episode of severe RSV illness was USD 329 (95% confidence interval (95% CI): 251-408 ) in Kilifi and USD 527 (95% CI: 405- 649) in Siaya. Household costs were USD 67 (95% CI: 54-80) and USD 172 (95% CI: 131- 214) in Kilifi and Siaya, respectively. Mean direct medical costs to the household during hospitalization were USD 11 (95% CI: 10-12) and USD 67 (95% CI: 51-83) among Kilifi and Siaya participants, respectively. Observed costs were lower in Kilifi due to differences in healthcare administration. CONCLUSIONS: RSV-associated disease among young children leads to a substantial economic burden to both families and the health system in Kenya. This burden may differ between Counties in Kenya and similar multi-site studies are advised to support cost-effectiveness analyses.

Influenza viruses undergo rapid evolutionary changes, which requires continuous surveillance to monitor for genetic and potential antigenic changes in circulating viruses that can guide control and prevention decision making. We sequenced and phylogenetically analyzed A(H1N1)pdm09 virus genome sequences obtained from specimens collected from hospitalized patients of all ages with or without pneumonia between 2009 and 2018 from seven sentinel surveillance sites across Kenya. We compared these sequences with recommended vaccine strains during the study period to infer genetic and potential antigenic changes in circulating viruses and associations of clinical outcome. We generated and analyzed a total of 383 A(H1N1)pdm09 virus genome sequences. Phylogenetic analyses of HA protein revealed that multiple genetic groups (clades, subclades, and subgroups) of A(H1N1)pdm09 virus circulated in Kenya over the study period; these evolved away from their vaccine strain, forming clades 7 and 6, subclades 6C, 6B, and 6B.1, and subgroups 6B.1A and 6B.1A1 through acquisition of additional substitutions. Several amino acid substitutions among circulating viruses were associated with continued evolution of the viruses, especially in antigenic epitopes and receptor binding sites (RBS) of circulating viruses. Disease severity declined with an increase in age among children aged < 5 years. Our study highlights the necessity of timely genomic surveillance to monitor the evolutionary changes of influenza viruses. Routine influenza surveillance with broad geographic representation and whole genome sequencing capacity to inform on prioritization of antigenic analysis and the severity of circulating strains are critical to improved selection of influenza strains for inclusion in vaccines.

INTRODUCTION: Measurement error in gestational age (GA) may bias the association of GA with a health outcome. Ultrasound-based GA is considered the gold standard and is not readily available in low-resource settings. We corrected for measurement error in GA based on fundal height (FH) and date of last menstrual period (LMP) using ultrasound from the sub-cohort and adjusted for the bias in associating GA with neonatal mortality and low birth weight (< 2,500 grams, LBW). METHODS: We used data collected from 01/2015 to 09/2019 from pregnant women enrolled at two public hospitals in Siaya county, Kenya (N = 2,750). We used regression calibration to correct for measurement error in FH- and LMP-based GA accounting for maternal and child characteristics. We applied logistic regression to associate GA with neonatal mortality and low birth weight, with and without calibrating FH- and LMP-based GA. RESULTS: Calibration improved the precision of LMP (correlation coefficient, ρ from 0.48 to 0.57) and FH-based GA (ρ from 0.82 to 0.83). Calibrating FH/LMP-based GA eliminated the bias in the mean GA estimates. The log odds ratio that quantifies the association of GA with neonatal mortality increased by 29% (from -0.159 to -0.205) by calibrating FH-based GA and by more than twofold (from -0.158 to -0.471) by calibrating LMP-based GA. CONCLUSION: Calibrating FH/LMP-based GA improved the accuracy and precision of GA estimates and strengthened the association of GA with neonatal mortality/LBW. When assessing GA, neonatal public health and clinical interventions may benefit from calibration modeling in settings where ultrasound may not be fully available.

Background. Influenza viruses undergo rapid evolutionary changes, which requires continuous surveillance to monitor for genetic and potential antigenic changes in circulating viruses that can guide control and prevention decision making. Methods. We sequenced and phylogenetically analyzed A(H1N1)pdm09 virus genome sequences obtained from specimens collected from hospitalized patients of all ages with or without pneumonia between 2009 and 2018 from seven sentinel surveillance sites across Kenya. We compared these sequences with recommended vaccine strains during the study period to infer genetic and potential antigenic changes in circulating viruses and determinants of clinical outcome. Results. We generated and analyzed a total of 383 A(H1N1)pdm09 virus genome sequences. Phylogenetic analyses revealed that multiple genetic groups (clades, subclades, and subgroups) of A(H1N1)pdm09 virus circulated in Kenya over the study period; these evolved away from their vaccine strain, forming clades 7 and 6, subclades 6C, 6B, and 6B.1, and subgroups 6B.1A and 6B.1A1. Several amino acid substitutions among circulating viruses were associated with continued evolution of the viruses, especially in antigenic epitopes and receptor binding sites (RBS) of circulating viruses. Disease severity reduced with increase in age among children aged <5 years. Conclusion. Our study highlights the utility of genomic surveillance to monitor the evolutionary changes of influenza viruses. Routine influenza surveillance with broad geographic representation and whole genome sequencing capacity to inform on the severity of circulating strains could improve selection of influenza strains for inclusion in vaccines. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license.

Respiratory syncytial virus (RSV) is the predominant cause of acute lower respiratory infection (ALRI) in young children worldwide, yet no licensed RSV vaccine exists to help prevent the millions of illnesses and hospitalizations and tens of thousands of young lives taken each year. Monoclonal antibody (mAb) prophylaxis exists for prevention of RSV in a small subset of very high-risk infants and young children, but the only currently licensed product is impractical, requiring multiple doses and expensive for the low-income settings where the RSV disease burden is greatest. A robust candidate pipeline exists to one day prevent RSV disease in infant and pediatric populations, and it focuses on two promising passive immunization approaches appropriate for low-income contexts: maternal RSV vaccines and long-acting infant mAbs. Licensure of one or more candidates is feasible over the next one to three years and, depending on final product characteristics, current economic models suggest both approaches are likely to be cost-effective. Strong coordination between maternal and child health programs and the Expanded Program on Immunization will be needed for effective, efficient, and equitable delivery of either intervention. This 'Vaccine Value Profile' (VVP) for RSV is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations, and in collaboration with stakeholders from the WHO headquarters. All contributors have extensive expertise on various elements of the RSV VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection (LRTI) among infants under 6 months of age. Yet, in Kenya, little is known about healthcare workers' (HCWs) knowledge, attitudes, and perceptions around RSV disease and the prevention products under development. Between September and October 2021, we conducted a mixed methods cross-sectional survey to assess HCWs' knowledge, attitudes, and perceptions of RSV disease and RSV vaccinations in two counties. We enrolled HCWs delivering services directly at maternal and child health (MCH) departments in selected health facilities (frontline HCWs) and health management officers (HMOs). Of the 106 respondents, 94 (88.7%) were frontline HCWs, while 12 were HMOs. Two of the HMOs were members of the Kenya National Immunization Technical Advisory Group (KENITAG). Of the 104 non-KENITAG HCWs, only 41 (39.4%) had heard about RSV disease, and 38/41 (92.7%) felt that pregnant women should be vaccinated against RSV. Most participants would recommend a single-dose vaccine schedule (n = 62, 58.5%) for maximal adherence and compliance (n = 38/62, 61.3%), single dose/device vaccines (n = 50/86, 58.1%) to prevent wastage and contamination, and maternal vaccination through antenatal care clinics (n = 53, 50%). We found the need for increased knowledge about RSV disease and prevention among Kenyan HCWs.

BACKGROUND: Respiratory syncytial virus (RSV) is among the leading childhood causes of viral pneumonia worldwide. Establishing RSV-associated morbidity and mortality is important in informing the development, delivery strategies, and evaluation of interventions. METHODS: Using data collected during 2010-2018 from base regions (population-based surveillance studies in western Kenya and the Kilifi Health and Demographic Surveillance Study), we estimated age-specific rates of acute respiratory illness (ARI), severe acute respiratory illness (SARI-defined as hospitalization with cough or difficulty breathing with onset within the past 10 days), and SARI-associated deaths. We extrapolated the rates from the base regions to other regions of Kenya, while adjusting for risk factors of ARI and healthcare seeking behavior, and finally applied the proportions of RSV-positive cases identified from various sentinel and study facilities to the rates to obtain regional age-specific rates of RSV-associated outpatient and non-medically attended ARI and hospitalized SARI and severe ARI that was not hospitalized (non-hospitalized SARI). We applied age-specific RSV case fatality ratios to SARI to obtain estimates of RSV-associated in- and out-of-hospital deaths. RESULTS: Among Kenyan children aged < 5 years, the estimated annual incidence of outpatient and non-medically attended RSV-associated ARI was 206 (95% credible interval, CI; 186-229) and 226 (95% CI; 204-252) per 1000 children, respectively. The estimated annual rates of hospitalized and non-hospitalized RSV-associated SARI were 349 (95% CI; 303-404) and 1077 (95% CI; 934-1247) per 100,000 children respectively. The estimated annual number of in- and out-of-hospital deaths associated with RSV infection in Kenya were 539 (95% CI; 420-779) and 1921 (95% CI; 1495-2774), respectively. Children aged < 6 months had the highest burden of RSV-associated severe disease: 2075 (95% CI; 1818-2394) and 44 (95% CI 25-71) cases per 100,000 children for hospitalized SARI and in-hospital deaths, respectively. CONCLUSIONS: Our findings suggest a substantial disease burden due to RSV infection, particularly among younger children. Prioritizing development and use of maternal vaccines and affordable long-lasting monoclonal antibodies could help reduce this burden.

BACKGROUND: Understanding healthcare-seeking patterns for respiratory illness can help improve estimation of disease burden and target public health interventions to control acute respiratory disease in Kenya. METHODS: We conducted a cross-sectional survey to determine healthcare utilization patterns for acute respiratory illness (ARI) and severe pneumonia in four diverse counties representing urban, peri-urban, rural mixed farmers, and rural pastoralist communities in Kenya using a two-stage (sub-locations then households) cluster sampling procedure. Healthcare seeking behavior for ARI episodes in the last 14 days, and severe pneumonia in the last 12 months was evaluated. Severe pneumonia was defined as reported cough and difficulty breathing for > 2 days and report of hospitalization or recommendation for hospitalization, or a danger sign (unable to breastfeed/drink, vomiting everything, convulsions, unconscious) for children < 5 years, or report of inability to perform routine chores. RESULTS: From August through September 2018, we interviewed 28,072 individuals from 5,407 households. Of those surveyed, 9.2% (95% Confidence Interval [CI] 7.9-10.7) reported an episode of ARI, and 4.2% (95% CI 3.8-4.6) reported an episode of severe pneumonia. Of the reported ARI cases, 40.0% (95% CI 36.8-43.3) sought care at a health facility. Of the74.2% (95% CI 70.2-77.9) who reported severe pneumonia and visited a medical health facility, 28.9% (95% CI 25.6-32.6) were hospitalized and 7.0% (95% CI 5.4-9.1) were referred by a clinician to the hospital but not hospitalized. 21% (95% CI 18.2-23.6) of self-reported severe pneumonias were hospitalized. Children aged < 5 years and persons in households with a higher socio-economic status were more likely to seek care for respiratory illness at a health facility. CONCLUSION: Our findings suggest that hospital-based surveillance captures less than one quarter of severe pneumonia in the community. Multipliers from community household surveys can account for underutilization of healthcare resources and under-ascertainment of severe pneumonia at hospitals.

BACKGROUND: The impact of Human Immunodeficiency Virus (HIV) on pregnancy outcomes for women on antiretroviral therapy (ART) in sub-Saharan Africa remains unclear. METHODS: Pregnant women in Kenya were enrolled in the second trimester and followed up to delivery. We estimated effects of treated HIV with three pregnancy outcomes: loss, premature birth, and low birthweight and factors associated with HIV-positive status. RESULTS: Of 2,113 participants, 311 (15%) were HIV-infected and on ART. Ninety-one of 1,762 (5%) experienced a pregnancy loss, 169/1,725 (10%) a premature birth (<37 weeks), and 74/1,317 (6%) had a low birthweight newborn (<2500g).There was no evidence of associations between treated HIV infection and pregnancy loss (adjusted relative risk [aRR]: 1.19 [95% confidence interval: 0.65-2.16], p=0.57), prematurity (1.09 [0.70-1.70], p=0.69) and low birthweight (1.36 [0.77-2.40], p=0.27). Factors associated with an HIV-positive status included older age, food insecurity, lower education level, higher parity, lower gestation at first antenatal clinic, anemia, and syphilis. Women who were overweight or underweight were less likely to be HIV infected compared to those with normal weight. CONCLUSION: Currently treated HIV was not significantly associated with adverse pregnancy outcomes. HIV-infected women, however, had a higher prevalence of other factors associated with adverse pregnancy outcomes.

BACKGROUND: In tropical Africa, data about influenza-associated illness burden are needed to assess potential benefits of influenza vaccination among pregnant women. We estimated the incidence of influenza among pregnant women and their infants in Siaya County, Kenya. METHODS: We enrolled women at <31 weeks of gestation and conducted weekly follow-up until 6-month postpartum to identify acute respiratory illnesses (ARIs). We defined ARI among mothers as reported cough, rhinorrhoea or sore throat and among infants as maternal-reported cough, difficulty breathing, rhinorrhoea or clinician diagnosis of respiratory illness. We collected nasal/nasopharyngeal and oropharyngeal swabs from mothers/infants with ARI and tested for influenza A and B using molecular assays. We calculated antenatal incidence of laboratory-confirmed influenza among mothers and postnatal incidence among mothers and infants. RESULTS: During June 2015 to May 2020, we analysed data from 3,026 pregnant women at a median gestational age of 16weeks (interquartile range [IQR], 13, 18) and followed 2,550 infants. Incidence of laboratory-confirmed influenza during pregnancy (10.3 episodes per 1,000person-months [95% confidence interval {CI} 8.6-11.8]) was twofold higher than in the postpartum period (4.0 [95% CI 2.6-5.5]; p<0.01). Incidence was significantly higher among human immunodeficiency virus (HIV)-infected pregnant women (15.6 [95% CI 11.0-20.6] vs. 9.1 [95% CI 7.5-10.8]; p<0.01). Incidence among young infants was 4.4 (95% CI 3.0-5.9) and similar among HIV-exposed and HIV-unexposed infants. CONCLUSION: Our findings suggest a substantial burden of influenza illnesses during pregnancy, with a higher burden among HIV-infected mothers. Kenyan authorities should consider the value of vaccinating pregnant women, especially if HIV infected.

We determined incidence of severe acute respiratory syndrome coronavirus 2 and influenza virus infections among pregnant and postpartum women and their infants in Kenya during 2020-2021. Incidence of severe acute respiratory syndrome coronavirus 2 was highest among pregnant women, followed by postpartum women and infants. No influenza virus infections were identified.

Understanding respiratory syncytial virus (RSV) circulation patterns is necessary to guide the timing of limited-duration interventions such as vaccines. We describe RSV circulation over multiple seasons in three distinct counties of Kenya during 2006-2018. Kilifi and Siaya counties each had consistent but distinct RSV seasonality, lasting on average 18-22 weeks. Based on data from available years, RSV did not have a clear pattern of circulation in Nairobi. This information can help guide the timing of vaccines and immunoprophylaxis products that are under development.

BACKGROUND: Respiratory syncytial virus (RSV) is an important cause of respiratory illness worldwide, however, burden data on mother-infant pairs remain sparse in sub-Saharan Africa where HIV is prevalent. We evaluated the impact of maternal HIV infection on the burden of RSV among mothers and their infants in western Kenya. METHODS: We enrolled pregnant women (≤20 weeks gestation) and followed them and their newborns weekly for up to 3-6 months post-partum, to document cases of acute respiratory illness (ARI). Nasal/ oropharyngeal swabs were collected and tested for RSV using polymerase chain reaction. Analyses were stratified by maternal HIV-status, and incidence computed per 1,000 person-months. RESULTS: Compared to RSV-negative ARI cases, RSV-positive cases were associated with cough, apnoea and hospitalization among infants. RSV incidence per 1,000 person-months among mothers was 4.0 (95% confidence interval (CI), 3.2-4.4), and was twice that among the HIV-infected (8.4; 95% CI, 5.7-12.0) compared to the HIV-uninfected mothers (3.1; 95% CI 2.3-4.0). Among infants, incidence per 1,000 person-months was 15.4 (95% CI, 12.5-18.8); incidence did not differ by HIV exposure or prematurity. CONCLUSION: HIV-infection may increase the risk of RSV illness among pregnant women. Future maternal RSV vaccines may have added benefit in high HIV prevalence areas.

Background: The impact of influenza B virus circulation in Sub-Saharan Africa is not well described. Methods: We analyzed data from acute respiratory illness (ARI) in Kenya. We assessed clinical features and age-specific hospitalization and outpatient visit rates by person-years for influenza B/Victoria and B/Yamagata and the extent to which circulating influenza B lineages in Kenya matched the vaccine strain component of the corresponding season (based on Northern Hemisphere [October-March] and Southern Hemisphere [April-September] vaccine availability). Results: From 2012 to 2016, influenza B represented 31% of all influenza-associated ARIs detected (annual range, 13-61%). Rates of influenza B hospitalization and outpatient visits were higher for <5 vs >/=5 years. Among <5 years, B/Victoria was associated with pneumonia hospitalization (64% vs 44%; P = .010) and in-hospital mortality (6% vs 0%; P = .042) compared with B/Yamagata, although the mean annual hospitalization rate for B/Victoria was comparable to that estimated for B/Yamagata. The 2 lineages co-circulated, and there were mismatches with available trivalent influenza vaccines in 2/9 seasons assessed. Conclusions: Influenza B causes substantial burden in Kenya, particularly among children aged <5 years, in whom B/Victoria may be associated with increased severity. Our findings suggest a benefit from including both lineages when considering influenza vaccination in Kenya.

BACKGROUND: Data on congenital cytomegalovirus (CMV) infection in Africa are limited. OBJECTIVE: To describe the prevalence of congenital CMV infection in a population with high prevalence of maternal HIV and malaria infection in western Kenya. STUDY DESIGN: We screened newborns for CMV by polymerase chain reaction assay of saliva swabs and dried blood spots (DBS), and assessed maternal CMV immunoglobulin G (IgG) status by testing serum eluted from newborn's DBS. We calculated adjusted prevalence ratios (aPRs) using log-binomial regression models. RESULTS: Among 1066 mothers, 210 (19.7%) had HIV infection and 207 (19.4%) had malaria infection; 33 (3.1%) mothers had both. Maternal CMV IgG prevalence was 93.1% (95% confidence interval [CI]: 88.3%-96.0%). Among 1078 newborns (12 sets of twins), 39 (3.6%, 95% CI: 2.7-4.9%) were CMV positive. The prevalence of congenital CMV infection by maternal HIV and malaria infection status was 5.0% (95% CI: 2.7-9.2%) for HIV only, 5.1% (95% CI: 2.7-9.4%) for malaria only, 8.8 (95% CI: 3.1-23.0) for HIV and malaria co-infection, and 2.6% (95% CI: 1.7-4.1%) for none. Congenital CMV infection was independently associated with maternal HIV infection (aPR=2.1; 95% CI: 1.0-4.2), adjusting for maternal age, parity, and malaria infection. CONCLUSIONS: The prevalence of congenital CMV infection was higher than the 0.2-0.7% in developed countries. Maternal HIV infection may increase the risk of congenital CMV infection, but the role of maternal malaria on intrauterine transmission of CMV remains unclear.

Molecular diagnostic methods are becoming increasingly available for assessment of acute lower respiratory illnesses (ALRI). However, nasopharyngeal/oropharyngeal (NP/OP) swabs may not accurately reflect etiologic agents from the lower respiratory tract where sputum specimens are considered as a more representative sample. The pathogen yields from NP/OP against sputum specimens have not been extensively explored, especially in tropical countries. We compared pathogen yields from NP/OP swabs and sputum specimens from patients ≥18 years hospitalized with ALRI in rural Western Kenya. Specimens were tested for 30 pathogens using TaqMan Array Cards (TAC) and results compared using McNemar’s test. The agreement for pathogen detection between NP/OP and sputum specimens ranged between 85–100%. More viruses were detected from NP/OP specimens whereas Klebsiella pneumoniae and Mycobacterium tuberculosis were more common in sputum specimens. There was no clear advantage in using sputum over NP/OP specimens to detect pathogens of ALRI in adults using TAC in the context of this tropical setting.

BACKGROUND: In order to better understand respiratory syncytial virus (RSV) epidemiology and burden in tropical Africa, optimal case definitions for detection of RSV cases need to be identified. METHODS: We used data collected between September 2009 - August 2013 from children aged <5 years hospitalized with acute respiratory Illness at Siaya County Referral Hospital. We evaluated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of individual signs, symptoms and standard respiratory disease case definitions (severe acute respiratory illness [SARI]; hospitalized influenza-like illness [hILI]; integrated management of childhood illness [IMCI] pneumonia) to detect laboratory-confirmed RSV infection. We also evaluated an alternative case definition of cough or difficulty breathing plus hypoxia, in-drawing, or wheeze. RESULTS: Among 4714 children hospitalized with ARI, 3810 (81 %) were tested for RSV; and 470 (12 %) were positive. Among individual signs and symptoms, cough alone had the highest sensitivity to detect laboratory-confirmed RSV [96 %, 95 % CI (95-98)]. Hypoxia, wheezing, stridor, nasal flaring and chest wall in-drawing had sensitivities ranging from 8 to 31 %, but had specificities >75 %. Of the standard respiratory case definitions, SARI had the highest sensitivity [83 %, 95 % CI (79-86)] whereas IMCI severe pneumonia had the highest specificity [91 %, 95 % CI (90-92)]. The alternative case definition (cough or difficulty breathing plus hypoxia, in-drawing, or wheeze) had a sensitivity of [55 %, 95 % CI (50-59)] and a specificity of [60 %, 95 % CI (59-62)]. The PPV for all case definitions and individual signs/symptoms ranged from 11 to 20 % while the negative predictive values were >87 %. When we stratified by age <1 year and 1- < 5 years, difficulty breathing, severe pneumonia and the alternative case definition were more sensitive in children aged <1 year [70 % vs. 54 %, p < 0.01], [19 % vs. 11 %, p = 0.01] and [66 % vs. 43 %, p < 0.01] respectively, while non-severe pneumonia was more sensitive [14 % vs. 26 %, p < 0.01] among children aged 1- < 5 years. CONCLUSION: The sensitivity and specificity of different commonly used case definitions for detecting laboratory-confirmed RSV cases varied widely, while the positive predictive value was consistently low. Optimal choice of case definition will depend upon study context and research objectives.

Influenza-associated acute lower respiratory infections cause a considerable burden of disease in rural and urban sub-Saharan Africa communities with the greatest burden among children. Currently, vaccination is the best way to prevent influenza infection and accompanying morbidities. We examined geographic, socio-economic and demographic factors that contributed to acceptance of childhood seasonal influenza vaccination among children living in a population-based morbidity surveillance system in rural western Kenya, where influenza vaccine was offered free-of-charge to children 6 months-10 years old from April to June, 2011. We evaluated associations between maternal and household demographic variables, socio-economic status, and distance from home to vaccination clinics with family vaccination status. 7249 children from 3735 households were eligible for vaccination. Of these, 2675 (36.9%) were fully vaccinated, 506 (7.0%) were partially vaccinated and 4068 (56.1%) were not vaccinated. Children living in households located >5km radius from the vaccination facilities were significantly less likely to be vaccinated (aOR=0.70; 95% CI 0.54-0.91; p=0.007). Children with mothers aged 25-34 and 35-44 years were more likely to be vaccinated than children with mothers less than 25 years of age (aOR=1.36; 95% CI 1.15-1.62; p<0.001; and aOR=1.35; 95% CI 1.10-1.64; p=0.003, respectively). Finally, children aged 2-5 years and >5 years of age (aOR=1.38; 95% CI 1.20-1.59; p<0.001; and aOR=1.41; 95% CI 1.23-1.63; p<0.001, respectively) and who had a sibling hospitalized within the past year (aOR=1.73; 95% CI 1.40-2.14; p<0.001) were more likely to be vaccinated. Shorter distance from the vaccination center, older maternal and child age, household administrator's occupation that did not require them to be away from the home, and having a sibling hospitalized during the past year were associated with increased likelihood of vaccination against influenza in western Kenya. These findings should inform the design of future childhood seasonal influenza vaccination campaigns in rural Kenya, and perhaps elsewhere in Africa.