Vaccine effectiveness against influenza hospitalisation in adults during the 2022/2023 mixed season of influenza A(H1N1)pdm09, A(H3N2) and B circulation, Europe: VEBIS SARI VE hospital network.

We conducted a multicentre hospital-based test-negative case-control study to measure vaccine effectiveness (VE) against PCR-confirmed influenza in adult patients with severe acute respiratory infection (SARI) during the 2022/2023 influenza season in Europe. Among 5547 SARI patients ≥18 years, 2963 (53%) were vaccinated against influenza. Overall VE against influenza A(H1N1)pdm09 was 11% (95% CI: -23-36); 20% (95% CI: -4-39) against A(H3N2) and 56% (95% CI: 22-75) against B. During the 2022/2023 season, while VE against hospitalisation with influenza B was >55%, it was ≤20% for influenza A subtypes. While influenza vaccination should be a priority for future seasons, improved vaccines against influenza are needed.

Enhanced surveillance of hospitalized COVID-19 patients in Europe: an evaluation of the I-MOVE-COVID-19 surveillance network.

BACKGROUND: A pre-existing, well-established European influenza surveillance network known as I-MOVE enabled the rapid implementation of a European multi-country COVID-19 hospital surveillance network for surveillance of hospitalized COVID-19 cases in early 2020. This network included 257 hospitals in 11 surveillance sites across nine countries. We aimed to identify whether the surveillance objectives were relevant to public health actions, whether the surveillance system met its objectives, where and how shortcomings could be improved, and whether the system was sustainable. METHODS: We identified six key attributes (meeting objectives, usefulness, timeliness, data quality, simplicity and sustainability) to assess, using Centers for Disease Control and Prevention's evaluation framework. We analyzed pooled datasets, held interviews and group discussions with 10 participating and coordinating sites and gathered feedback through web surveys. RESULTS: There was overall agreement that the surveillance objectives had been met and being involved in a network of European partners had additional important benefits for stakeholders. While the publication of the outputs was not always sufficiently timely, data submission processes were considered straightforward and the key surveillance variables (age, sex, hospital admission and mortality data) were complete. The main challenges were identified as the collection of the large number of variables, limited available human resources and information governance and data protection laws. CONCLUSIONS: I-MOVE-COVID-19 delivered relevant and accurate data supporting the development and implementation of COVID-19 surveillance. Recommendations presented here identify learning opportunities to support preparedness and surveillance response for future pandemics. The applied evaluation framework in this study can be adapted for other European surveillance system evaluations.

Anthropometric cut-offs to identify hyperglycemia in an Afro-Caribbean population: a cross-sectional population-based study from Barbados.

INTRODUCTION: Body mass index (BMI) and waist circumference (WC) cut-offs associated with hyperglycemia may differ by ethnicity. We investigated the optimal BMI and WC cut-offs for identifying hyperglycemia in the predominantly Afro-Caribbean population of Barbados. RESEARCH DESIGN AND METHODS: A cross-sectional study of 865 individuals aged ≥25 years without known diabetes or cardiovascular disease was conducted. Hyperglycemia was defined as fasting plasma glucose ≥5.6 mmol/L or hemoglobin A1c ≥5.7% (39 mmol/mol). The Youden index was used to identify the optimal cut-offs from the receiver operating characteristic (ROC) curves. Further ROC analysis and multivariable log binomial regression were used to compare standard and data-derived cut-offs. RESULTS: The prevalence of hyperglycemia was 58.9% (95% CI 54.7% to 63.0%). In women, optimal BMI and WC cut-offs (27 kg/m2 and 87 cm, respectively) performed similarly to standard cut-offs. In men, sensitivities of the optimal cut-offs of BMI ≥24 kg/m2 (72.0%) and WC ≥86 cm (74.0%) were higher than those for standard BMI and WC obesity cut-offs (30.0% and 25%-46%, respectively), although with lower specificity. Hyperglycemia was 70% higher in men above the data-derived WC cut-off (prevalence ratio 95% CI 1.2 to 2.3). CONCLUSIONS: While BMI and WC cut-offs in Afro-Caribbean women approximate international standards, our findings, consistent with other studies, suggest lowering cut-offs in men may be warranted to improve detection of hyperglycemia. Our findings do, however, require replication in a new data set.

Ultra-processed food consumption in Barbados: evidence from a nationally representative, cross-sectional study.

Our objective was to describe, for the first time in an English-speaking Caribbean country, the contribution of ultra-processed foods (UPFs) to nutrients linked to non-communicable disease. Using a cross-sectional study design, dietary data were collected from two non-consecutive 24-h dietary recalls. Recorded food items were then classified according to their degree of processing by the NOVA system. The present study took place in Barbados (2012-13). A representative population-based sample of 364 adult Barbadians (161 males and 203 females) aged 25-64 years participated in the study. UPFs represented 40⋅5 % (838 kcal/d; 95 % CI 791, 885) of mean energy intake. Sugar-sweetened beverages made the largest contribution to energy within the UPF category. Younger persons (25-44 years) consumed a significantly higher proportion of calories from UPF (NOVA group 4) compared with older persons (45-64 years). The mean energy shares of UPF ranged from 22⋅0 to 58⋅9 % for those in the lowest tertile to highest tertile. Within each tertile, the energy contribution was significantly higher in the younger age group (25-44 years) compared with the older (45-64 years). One-quarter of persons consume ≥50 % of their daily calories from UPF, this being significantly higher in younger persons. The ultra-processed diet fraction contained about six times the mean of free sugars and about 0⋅8 times the dietary fibre of the non-ultra-processed fraction (NOVA groups 1-3). Targeted interventions to decrease the consumption of UPF especially in younger persons is thus of high priority to improve the diet quality of Barbadians.

Nutritional adequacy and dietary disparities in an adult Caribbean population of African descent with a high burden of diabetes and cardiovascular disease.

The Caribbean island of Barbados has a high burden of diabetes and cardiovascular disease. Dietary habits were last described in 2005. A representative population-based sample (n = 363, aged 25-64 years) provided two nonconsecutive 24-hr dietary recalls in this cross-sectional study. Mean daily nutrient intakes were compared with the Dietary Guidelines for Americans. Subgroup differences by age, sex, and educational level were examined using logistic regression. High sugar intakes exist for both sexes with 24% (95% CIs 18.9, 30.0) consuming less than the recommended <10% of energy from added sugars (men 22%; 15.0, 31.6; women 26%; 18.9, 33.7). Sugar-sweetened beverages provide 43% (42.2%, 44.4%) of total sugar intake. Inadequate dietary fiber intakes (men 21 g, 18.2, 22.8; women 18 g, 16.7, 18.9) exist across all age groups. Inadequate micronutrient intake was found in women for calcium, folate, thiamine, zinc, and iron. Older persons (aged 45-64 years) were more likely to report adequacy of dietary fiber (OR = 2.7, 1.5, 4.8) and iron (OR = 3.0, 1.7, 5.3) than younger persons (aged 25-44). Older persons (aged 45-64 years) were less likely to have an adequate supply of riboflavin (OR = 0.4, 0.2, 0.6) than younger persons. Men were more likely to have adequate intakes of iron (OR = 13.0, 6.1, 28.2), folate (OR = 2.4, 1.3, 4.6), and thiamine (OR = 3.0, 1.5, 5.0) than women. Education was not associated with nutrient intake. The Barbadian diet is characterized by high sugar intakes and inadequate dietary fiber; a nutrient profile associated with an increased risk of obesity, type 2 diabetes, and related noncommunicable diseases.

Vaccine effectiveness against influenza A(H3N2) and B among laboratory-confirmed, hospitalised older adults, Europe, 2017-18: A season of B lineage mismatched to the trivalent vaccine.

BACKGROUND: Influenza A(H3N2), A(H1N1)pdm09 and B viruses co-circulated in Europe in 2017-18, predominated by influenza B. WHO-recommended, trivalent vaccine components were lineage-mismatched for B. The I-MOVE hospital network measured 2017-18 seasonal influenza vaccine effectiveness (IVE) against influenza A(H3N2) and B among hospitalised patients (≥65 years) in Europe. METHODS: Following the same generic protocol for test-negative design, hospital teams in nine countries swabbed patients ≥65 years with recent onset (≤7 days) severe acute respiratory infection (SARI), collecting information on demographics, vaccination status and underlying conditions. Cases were RT-PCR positive for influenza A(H3N2) or B; controls: negative for any influenza. "Vaccinated" patients had SARI onset >14 days after vaccination. We measured pooled IVE against influenza, adjusted for study site, age, sex, onset date and chronic conditions. RESULTS: We included 3483 patients: 376 influenza A(H3N2) and 928 B cases, and 2028 controls. Most (>99%) vaccinated patients received the B lineage-mismatched trivalent vaccine. IVE against influenza A(H3N2) was 24% (95% CI: 2 to 40); 35% (95% CI: 6 to 55) in 65- to 79-year-olds and 14% (95% CI: -22 to 39) in ≥80-year-olds. Against influenza B, IVE was 30% (95% CI: 16 to 41); 37% (95% CI: 19 to 51) in 65- to 79-year-olds and 19% (95% CI: -7 to 38) in ≥80-year-olds. CONCLUSIONS: IVE against influenza B was similar to A(H3N2) in hospitalised older adults, despite trivalent vaccine and circulating B lineage mismatch, suggesting some cross-protection. IVE was lower in those ≥80 than 65-79 years. We reinforce the importance of influenza vaccination in older adults as, even with a poorly matched vaccine, it still protects one in three to four of this population from severe influenza.

Are there gender differences in acute management and secondary prevention of acute coronary syndromes in Barbados? A cohort study.

OBJECTIVES: In Barbados, high case fatality rates have been reported after myocardial infarction (MI) with higher rates in women than men. To explore this inequality, we examined documented pharmacological interventions for ST-segment elevated myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable and chronic angina in women and men. DESIGN: Prospective cohort registry data for STEMI and NSTEMI and retrospective chart review for unstable and chronic angina. SETTING: Tertiary care (acute coronary syndromes) and primary care (chronic angina) centres in Barbados. PARTICIPANTS: For the years 2009-2016, a total of 1018 patients with STEMI or NSTEMI were identified via the prospective study. For unstable and chronic angina, 136 and 272 notes were reviewed respectively for the years 2010-2014. OUTCOME MEASURES: The proportions of patients prescribed recommended medication during the first 24 hours after an acute event, at discharge and for chronic care were calculated. Prescribed proportions were analysed by gender after adjustment for age. RESULTS: Between 2009 and 2016, for the acute management of patients with NSTEMI and STEMI, only two (aspirin and clopidogrel) of six drugs had documented prescription rates of 80% or more. Patients with STEMI (n=552) had higher prescription rates than NSTEMI (n=466), with gender differences being more pronounced in the former. Among patients with STEMI, after adjustment for age, diabetes, hypertension and smoking, men were more likely to receive fibrinolytics acutely, OR 2.28 (95% CI 1.24 to 4.21). Compared with men, a higher proportion of women were discharged on all recommended treatments; this was only statistically significant for beta-blockers: age-adjusted OR 1.87 (95% CI 1.16 to 3.00). There were no statistically significant differences in documented prescription of drugs for chronic angina. CONCLUSION: Following acute MI in Barbados, the proportion of patients with documented recommended treatment is relatively low. Although women were less likely to receive appropriate acute care than men, by discharge gender differences were reversed.

Sodium and potassium excretion in an adult Caribbean population of African descent with a high burden of cardiovascular disease.

BACKGROUND: High sodium diets with inadequate potassium and high sodium-to-potassium ratios are a known determinant of hypertension and cardiovascular disease (CVD). The Caribbean island of Barbados has a high prevalence of hypertension and mortality from CVD. Our objectives were to estimate sodium and potassium excretion, to compare estimated levels with recommended intakes and to identify the main food sources of sodium in Barbadian adults. METHODS: A sub-sample (n = 364; 25-64 years) was randomly selected from the representative population-based Health of the Nation cross-sectional study (n = 1234), in 2012-13. A single 24-h urine sample was collected from each participant, following a strictly applied protocol designed to reject incomplete samples, for the measurement of sodium and potassium excretion (in mg), which were used as proxy estimates of dietary intake. In addition, sensitivity analyses based on estimated completeness of urine collection from urine creatinine values were undertaken. Multiple linear regression was used to examine differences in sodium and potassium excretion, and the sodium-to-potassium ratio, by age, sex and educational level. Two 24-h recalls were used to identify the main dietary sources of sodium. All analyses were weighted for the survey design. RESULTS: Mean sodium excretion was 2656 (2488-2824) mg/day, with 67% (62-73%) exceeding the World Health Organization (WHO) recommended limit of 2000 mg/d. Mean potassium excretion was 1469 (1395-1542) mg/d; < 0.5% met recommended minimum intake levels. Mean sodium-to-potassium ratio was 2.0 (1.9-2.1); not one participant had a ratio that met WHO recommendations. Higher potassium intake and lower sodium-to-potassium ratio were independently associated with age and tertiary education. Sensitivity analyses based on urine creatinine values did not notably alter these findings. CONCLUSIONS: In this first nationally representative study with objective assessment of sodium and potassium excretion in a Caribbean population in over 20 years, levels of sodium intake were high, and potassium intake was low. Younger age and lower educational level were associated with the highest sodium-to-potassium ratios. These findings provide baseline values for planning future policy interventions for non-communicable disease prevention.

Managing acute ischaemic stroke in a small island developing state: meeting the guidelines in Barbados.

BACKGROUND: We describe hospital-based management of acute ischaemic stroke patients in 2010-2013 in Barbados, by comparing documented treatment given in the single tertiary public hospital with international guideline recommendations. METHODS: Evidence-based stroke management guidelines were identified through a systematic literature search. Comparisons were made between these guidelines and documented diagnostic practice (all strokes) and prescribed medication (ischaemic stroke only), using a combination of key informant interviews and national stroke registry data for 2010-2013. RESULTS: Several published international guidelines for the acute management of ischaemic stroke recommended patient management in a dedicated stroke unit or nearest hospital specialised in stroke care. Further, patients should receive clinical diagnosis, CT brain scan, specialist evaluation by a multidisciplinary team and, if eligible, thrombolysis with alteplase within 3-3.5 h of symptom onset. Subsequent secondary prophylaxis, with a platelet aggregation inhibitor and a statin was advised. Barbados had no stroke unit or stroke team, and no official protocol for acute stroke management during the study period. Most of the 1735 stroke patients were managed by emergency physicians at presentation; if admitted, they were managed on general medical wards. Most had a CT scan (1646; 94.9%). Of 1406 registered ischaemic stroke patients, only 6 (0.4%) had been thrombolysed, 521 (37.1%) received aspirin within 24 h of admission and 670 (47.7%) were prescribed aspirin on discharge. CONCLUSIONS: Acute ischaemic stroke diagnosis was consistent with international recommendations, although this was less evident for treatment. While acknowledging the difficulty in implementing international guidelines in a low-resource setting, there is scope for improvement in acute ischaemic stroke management and/or its documentation in Barbados. A stroke unit was established in August 2013 and written clinical protocols for acute stroke care were in development at the time of the study; future registry data will evaluate their impact. Our findings have implications for other low-resource settings with high stroke burden.

Economic assessment of integrated cancer and cardiovascular registries: The Barbados experience.

BACKGROUND: This report describes the resources required to support the integrated approach of the Barbados National Registry for Chronic Non-communicable Diseases (BNR) to non-communicable disease (NCD) case registration, and to identify differences in cost for collecting and maintaining information on cancer and cardiovascular disease (CVD) case registration. METHODS: We used the modified Centers for Disease Control and Prevention's International Registry Costing Tool to collect data from the CVD and cancer registries. We used cancer and CVD cost data for the annual period April 2014 through March 2015 to estimate the total cost and cost per case. We used prospectively collected average annual CVD cases, and for cancer cases we assumed 2 or 3 years are needed for retrospective data collection. RESULTS: The Ministry of Health provided 56% of the resources for the registries. Labor accounted for over 70% of both registries' budgets, while management and administration, along with data collection and analysis, incurred the highest costs per case. Total variable cost activities related to data collection and analysis were higher for the CVD component (US$131,297) than the cancer component (US$58,917). The CVD cost per case (US$489) was in between the cancer 2-year (US$382) and the cancer 3-year (US$573) cost-per-case estimates. CONCLUSION: These findings indicate that there are substantial fixed costs related to management and administration of NCD registries. All registries need management and administration support. When registries are combined, management and administration costs can be shared. We project that registries that can share fixed-cost infrastructure are likely to incur a lower total cost per case.

Predicting the burden of acute myocardial infarction in a country with limited resources: combining data from routine sources.

BACKGROUND: Prior to implementation of a national surveillance system for cardiovascular disease in Barbados, a small island state with limited health resources, the national burden of acute myocardial infarction (MI) was unknown. METHODS: We retrospectively estimated national acute MI incidence rates (IRs) per 100,000 during the decade before registry implementation (1999-2008), using easily accessible routine data from different sources, assessing changes over time through Poisson regression. Future events (2009-2013) were estimated using simple sensitivity analysis to incorporate prediction uncertainty. Model predictions were compared with actual IRs from initial years of the registry. RESULTS: In 2000, crude IR was 85.5 (95% CI: 74.9-97.2), rising to 92.1 (81.2-103.9) in 2008. Accounting for population ageing, the model anticipated IR of 115.9 in 2010 (99.7-132.1), vs actual crude IR 129.7 (115.9-144.6). CONCLUSIONS: Despite no electronic medical record system in Barbados, data were simple to collect, and provided a rough baseline for acute MI burden. We show that, in countries with small populations, limited resources and in absence of surveillance, national mortality statistics and routine hospital data can be combined to adequately model national estimates of acute MI incidence. This cheap and simple, yet fairly accurate method could be a key tool for other low-resource countries with ageing populations and increasing cardiovascular disease levels.

Advancing Cancer Control Through Research and Cancer Registry Collaborations in the Caribbean.

BACKGROUND: Few national registries exist in the Caribbean, resulting in limited cancer statistics being available for the region. Therefore, estimates are frequently based on the extrapolation of mortality data submitted to the World Health Organization. Thus, regional cancer surveillance and research need promoting, and their synergy must be strengthened. However, differences between countries outweigh similarities, hampering registration and availability of data. METHODS: The African-Caribbean Cancer Consortium (AC3) is a broad-based resource for education, training, and research on all aspects of cancer in populations of African descent. The AC3 focuses on capacity building in cancer registration in the Caribbean through special topics, training sessions, and biannual meetings. We review the results from selected AC3 workshops, including an inventory of established cancer registries in the Caribbean region, current cancer surveillance statistics, and a review of data quality. We then describe the potential for cancer research surveillance activities and the role of policymakers. RESULTS: Twelve of 30 Caribbean nations have cancer registries. Four of these nations provide high-quality incidence data, thus covering 14.4% of the population; therefore, regional estimates are challenging. Existing research and registry collaborations must pave the way and are facilitated by organizations like the AC3. CONCLUSIONS: Improved coverage for cancer registrations could help advance health policy through targeted research. Capacity building, resource optimization, collaboration, and communication between cancer surveillance and research teams are key to obtaining robust and complete data in the Caribbean.

Social distribution of diabetes, hypertension and related risk factors in Barbados: a cross-sectional study.

OBJECTIVE: To describe the distribution of diabetes, hypertension and related behavioural and biological risk factors in adults in Barbados by gender, education and occupation. DESIGN: Multistage probability sampling was used to select a representative sample of the adult population (≥ 25 years). Participants were interviewed using standard questionnaires, underwent anthropometric and blood pressure measurements, and provided fasting blood for glucose and cholesterol measurements. Standard WHO definitions were used. Data were weighted for sampling and non-response, and were age and sex standardised to the 2010 Barbados population. Weighted prevalence estimates were calculated, and prevalence ratios were calculated for behavioural and biological risk factors by demographic and socioeconomic group. RESULTS: Study response rate was 55.0%, with 764 women, 470 men. Prevalence of obesity was 33.8% (95% CI 30.7% to 37.1%); hypertension 40.6% (95% CI 36.5% to 44.9%); and diabetes 18.7% (95% CI 16.2% to 21.4%). Compared with women, men were less likely to be obese (prevalence ratio 0.5; 95% CI 0.4 to 0.7), or physically inactive (0.5; 0.4 to 0.6), but more likely to smoke tobacco (4.1; 2.5 to 6.7) and consume large amounts of alcohol in a single episode (4.6; 2.7 to 7.6). Both diabetes (0.83; 0.65 to 1.05) and hypertension (0.89; 0.79 to 1.02) were lower in men, but not significantly so. In women, higher educational level was related to higher fruit and vegetable intake, more physical activity, less diabetes and less hypercholesterolaemia (p 0.01-0.04). In men, higher education was related only to less smoking (p 0.04). Differences by occupation were limited to smoking in men and hypercholesterolaemia in women. CONCLUSIONS: In this developing country population, sex appears to be a much stronger determinant of behavioural risk factors, as well as obesity and its related risks, than education or occupation. These findings have implications for meeting the commitments made in the 2011 Rio Political Declaration, to eliminate health inequities.

Reconstruction of nonunion tibial fractures in war-wounded Iraqi civilians, 2006-2008: better late than never.

OBJECTIVE: To describe medical care and surgical outcome after functional reconstructive surgery in late-presenting patients who already had at least one prior operation. DESIGN: Retrospective review of medical care and surgical outcome from August 2006 to December 2008 using patient records for initial data with active follow-up for the latest outcome information. SETTING: Médecins sans Frontières surgical programme in Jordan Red Crescent Hospital, Amman, Jordan. PATIENTS: Sixty-two civilians with nonunion tibial fractures caused by war-related trauma in Iraq; 53 completed follow-up. INTERVENTION: Amputation and/or reconstruction. MAIN OUTCOME MEASUREMENTS: Late surgical complications (after the patient's return to Iraq) were analyzed for infection recurrence, bone union, and functional condition (defined using the Short Musculoskeletal Functional Assessment score). RESULTS: Almost three fourths of patients arrived with infected injuries, 9 of whom had amputation as the initial surgery; the rest, and all uninfected patients, had reconstruction. Excluding loss to follow-up, only 4 of 53 (8%) patients who arrived with an infected injury had infection recurrence. Excluding loss to follow-up and amputation, 2 of 14 (14%) patients in the uninfected and 5 of 30 (17%) in the infected injury group did not achieve successful tibial union. Mean Dysfunctional and Bothersome Indices overall were 27.1 and 29.8, respectively, with similar results for all 3 groups (amputations, uninfected, and infected injuries). CONCLUSIONS: Our study shows that patients with infected and uninfected injuries surgically treated in Amman achieved similar outcomes. Despite late presentation, our patients had a comparable outcome to other studies dealing with early reconstruction. Reconstruction for the infected group required longer treatment time. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A comparison of outcome for stroke patients in Barbados and South London.

BACKGROUND AND AIMS: Little is known about the poststroke outcome in Caribbean populations. We investigated differences in the activities of daily living, level of social activities, living circumstances and survival for stroke patients in Barbados and London. METHODS: Data were collected from the South London Stroke Register and the Barbados Register of Strokes for patients with a first-ever stroke registered between January 2001 and December 2004. The ability to perform activities of daily living was measured by the Barthel Index and level of social activities by the Frenchay Activities Index. Living circumstances were categorised into private household vs. institutional care. Death and dependency, activities of daily living and social activities were assessed at three-months, one- and two-years using logistic regression, adjusted for differences in demographic, socioeconomic and stroke severity characteristics. RESULTS: At three-months, a high level of social activities was more likely for the Barbados Register of Strokes (odds ratio 1.84; 95% confidence interval 1.03-3.29); there were no differences in activities of daily living; and Barbados Register of Strokes patients were less likely to be in institutional care (relative risk ratio 0.38; 95% confidence interval 0.18-0.79). Following adjustment, Barbados Register of Strokes patients had a higher risk of mortality at three-months (relative risk ratio 1.85; 95% confidence interval 1.03-3.30), one-year (relative risk ratio 1.83; 95% confidence interval 1.08-3.09) and two-years (relative risk ratio 1.82; 95% confidence interval 1.08-3.07). This difference was due to early poststroke deaths; for patients alive at four-weeks poststroke, survival thereafter was similar in both settings. CONCLUSIONS: In Barbados, there was evidence for a healthy survivor effect, and short-term social activity was greater than that in the South London Stroke Register.

Meningitis dipstick rapid test: evaluating diagnostic performance during an urban Neisseria meningitidis serogroup A outbreak, Burkina Faso, 2007.

Meningococcal meningitis outbreaks occur every year during the dry season in the "meningitis belt" of sub-Saharan Africa. Identification of the causative strain is crucial before launching mass vaccination campaigns, to assure use of the correct vaccine. Rapid agglutination (latex) tests are most commonly available in district-level laboratories at the beginning of the epidemic season; limitations include a short shelf-life and the need for refrigeration and good technical skills. Recently, a new dipstick rapid diagnostic test (RDT) was developed to identify and differentiate disease caused by meningococcal serogroups A, W135, C and Y. We evaluated the diagnostic performance of this dipstick RDT during an urban outbreak of meningitis caused by N. meningitidis serogroup A in Ouagadougou, Burkina Faso; first against an in-country reference standard of culture and/or multiplex PCR; and second against culture and/or a highly sensitive nested PCR technique performed in Oslo, Norway. We included 267 patients with suspected acute bacterial meningitis. Using the in-country reference standard, 50 samples (19%) were positive. Dipstick RDT sensitivity (N = 265) was 70% (95%CI 55-82) and specificity 97% (95%CI 93-99). Using culture and/or nested PCR, 126/259 (49%) samples were positive; dipstick RDT sensitivity (N = 257) was 32% (95%CI 24-41), and specificity was 99% (95%CI 95-100). We found dipstick RDT sensitivity lower than values reported from (i) assessments under ideal laboratory conditions (>90%), and (ii) a prior field evaluation in Niger [89% (95%CI 80-95)]. Specificity, however, was similar to (i), and higher than (ii) [62% (95%CI 48-75)]. At this stage in development, therefore, other tests (e.g., latex) might be preferred for use in peripheral health centres. We highlight the value of field evaluations for new diagnostic tests, and note relatively low sensitivity of a reference standard using multiplex vs. nested PCR. Although the former is the current standard for bacterial meningitis surveillance in the meningitis belt, nested PCR performed in a certified laboratory should be used as an absolute reference when evaluating new diagnostic tests.

Field evaluation of two rapid diagnostic tests for Neisseria meningitidis serogroup A during the 2006 outbreak in Niger.

The Pastorex((R)) (BioRad) rapid agglutination test is one of the main rapid diagnostic tests (RDTs) for meningococcal disease currently in use in the "meningitis belt". Earlier evaluations, performed after heating and centrifugation of cerebrospinal fluid (CSF) samples, under good laboratory conditions, showed high sensitivity and specificity. However, during an epidemic, the test may be used without prior sample preparation. Recently a new, easy-to-use dipstick RDT for meningococcal disease detection on CSF was developed by the Centre de Recherche Médicale et Sanitaire in Niger and the Pasteur Institute in France. We estimate diagnostic accuracy in the field during the 2006 outbreak of Neisseria meningitidis serogroup A in Maradi, Niger, for the dipstick RDT and Pastorex((R)) on unprepared CSF, (a) by comparing each test's sensitivity and specificity with previously reported values; and (b) by comparing results for each test on paired samples, using McNemar's test. We also (c) estimate diagnostic accuracy of the dipstick RDT on diluted whole blood. We tested unprepared CSF and diluted whole blood from 126 patients with suspected meningococcal disease presenting at four health posts. (a) Pastorex((R)) sensitivity (69%; 95%CI 57-79) was significantly lower than found previously for prepared CSF samples [87% (81-91); or 88% (85-91)], as was specificity [81% (95%CI 68-91) vs 93% (90-95); or 93% (87-96)]. Sensitivity of the dipstick RDT [89% (95%CI 80-95)] was similar to previously reported values for ideal laboratory conditions [89% (84-93) and 94% (90-96)]. Specificity, at 62% (95%CI 48-75), was significantly lower than found previously [94% (92-96) and 97% (94-99)]. (b) McNemar's test for the dipstick RDT vs Pastorex((R)) was statistically significant (p<0.001). (c) The dipstick RDT did not perform satisfactorily on diluted whole blood (sensitivity 73%; specificity 57%).Sensitivity and specificity of Pastorex((R)) without prior CSF preparation were poorer than previously reported results from prepared samples; therefore we caution against using this test during an epidemic if sample preparation is not possible. For the dipstick RDT, sensitivity was similar to, while specificity was not as high as previously reported during a more stable context. Further studies are needed to evaluate its field performance, especially for different populations and other serogroups.