Time to full enteral feeds in hospitalised preterm and very low birth weight infants in Nigeria and Kenya

BACKGROUND

Preterm (born < 37 weeks' gestation) and very low birthweight (VLBW; <1.5kg) infants are at the greatest risk of morbidity and mortality within the first 28 days of life. Establishing full enteral feeds is a vital aspect of their clinical care. Evidence predominantly from high income countries shows that early and rapid advancement of feeds is safe and reduces length of hospital stay and adverse health outcomes. However, there are limited data on feeding practices and factors that influence the attainment of full enteral feeds among these vulnerable infants in sub-Saharan Africa.

AIM

To identify factors that influence the time to full enteral feeds, defined as tolerance of 120ml/kg/day, in hospitalised preterm and VLBW infants in neonatal units in two sub-Saharan African countries.

METHODS

Demographic and clinical variables were collected for newborns admitted to 7 neonatal units in Nigeria and Kenya over 6-months. Multiple linear regression analysis was conducted to identify factors independently associated with time to full enteral feeds.

RESULTS

Of the 2280 newborn infants admitted, 484 were preterm and VLBW. Overall, 222/484 (45.8%) infants died with over half of the deaths (136/222; 61.7%) occurring before the first feed. The median (inter-quartile range) time to first feed was 46 (27, 72) hours of life and time to full enteral feeds (tFEF) was 8 (4.5,12) days with marked variation between neonatal units. Independent predictors of tFEF were time to first feed (unstandardised coefficient B 1.69; 95% CI 1.11 to 2.26; p value <0.001), gestational age (1.77; 0.72 to 2.81; <0.001), the occurrence of respiratory distress (-1.89; -3.50 to -0.79; <0.002) and necrotising enterocolitis (4.31; 1.00 to 7.62; <0.011).

CONCLUSION

The use of standardised feeding guidelines may decrease variations in clinical practice, shorten tFEF and thereby improve preterm and VLBW outcomes.

Marked variability in institutional deliveries and neonatal outcomes during the COVID-19 lockdown in Nigeria

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic and the interventions to mitigate its spread impacted access to healthcare, including hospital births and newborn care. This study evaluated the impact of COVID-19 lockdown measures on newborn service utilization in Nigeria.

METHODS

The records of women who delivered in hospitals and babies admitted to neonatal wards were retrospectively reviewed before (March 2019-February 2020) and during (March 2020-February 2021) the COVID-19 pandemic lockdown in selected facilities in Nigeria.

RESULTS

There was a nationwide reduction in institutional deliveries during the COVID-19 lockdown period in Nigeria, with 14 444 before and 11 723 during the lockdown-a decrease of 18.8%. The number of preterm admissions decreased during the lockdown period (30.6% during lockdown vs 32.6% pre-lockdown), but the percentage of outborn preterm admissions remained unchanged. Newborn admissions varied between zones with no consistent pattern. Although neonatal jaundice and prematurity remained the most common reasons for admission, severe perinatal asphyxia increased by nearly 50%. Neonatal mortality was significantly higher during the COVID-19 lockdown compared with pre-lockdown (110.6/1000 [11.1%] vs 91.4/1000 [9.1%], respectively; p=0.01). The odds of a newborn dying were about four times higher if delivered outside the facility during the lockdown (p<0.001).

CONCLUSIONS

The COVID-19 lockdown had markedly deleterious effects on healthcare seeking for deliveries and neonatal care that varied between zones with no consistent pattern.

Digital approaches to reducing TB treatment loss to follow-up

Poor adherence to TB treatment leads to adverse clinical outcomes. A range of digital technologies to support adherence have been developed and the COVID-19 pandemic considerably accelerated the implementation of digital interventions. Here, we review the current evidence on digital adherence support tools and update the findings of a previous review, with evidence published from 2018 to date. Interventional and observational studies, as well as primary and secondary analyses were included, and we summarised available evidence on effectiveness, cost-effectiveness and acceptability. The studies were heterogenous and varied in outcome measures and approaches used. Overall, our findings show that digital approaches, such as digital pillboxes and asynchronous video-observed treatment, are acceptable and have the potential to improve adherence and be cost-effective over time if implemented at scale. Digital tools should be part of multiple strategies to support adherence. Further research to integrate behavioural data on reasons for non-adherence will help to determine how to best implement these technologies in different settings.

Asymptomatic Plasmodium falciparum carriage and clinical disease: a 5-year community-based longitudinal study in The Gambia

BACKGROUND

Carriers of persistent asymptomatic Plasmodium falciparum infections constitute an infectious reservoir that maintains malaria transmission. Understanding the extent of carriage and characteristics of carriers specific to endemic areas could guide use of interventions to reduce infectious reservoir.

METHODS

In eastern Gambia, an all-age cohort from four villages was followed up from 2012 to 2016. Each year, cross-sectional surveys were conducted at the end of the malaria transmission season (January) and just before the start of the next one (June) to determine asymptomatic P. falciparum carriage. Passive case detection was conducted during each transmission season (August to January) to determine incidence of clinical malaria. Association between carriage at the end of the season and at start of the next one and the risk factors for this were assessed. Effect of carriage before start of the season on risk of clinical malaria during the season was also examined.

RESULTS

A total of 1403 individuals-1154 from a semi-urban village and 249 from three rural villages were enrolled; median age was 12 years (interquartile range [IQR] 6, 30) and 12 years (IQR 7, 27) respectively. In adjusted analysis, asymptomatic P. falciparum carriage at the end of a transmission season and carriage just before start of the next one were strongly associated (adjusted odds ratio [aOR] = 19.99; 95% CI 12.57-31.77, p < 0.001). The odds of persistent carriage (i.e. infected both in January and in June) were higher in rural villages (aOR = 13.0; 95% CI 6.33-26.88, p < 0.001) and in children aged 5-15 years (aOR = 5.03; 95% CI 2.47-10.23, p =  < 0.001). In the rural villages, carriage before start of the season was associated with a lower risk of clinical malaria during the season (incidence risk ratio [IRR] 0.48, 95% CI 0.27-0.81, p = 0.007).

CONCLUSIONS

Asymptomatic P. falciparum carriage at the end of a transmission season strongly predicted carriage just before start of the next one. Interventions that clear persistent asymptomatic infections when targeted at the subpopulation with high risk of carriage may reduce the infectious reservoir responsible for launching seasonal transmission.

Outcome of Community-Based Antiretroviral Drug Refill among Stable Human Immunodeficiency Virus Patients Accessing Care at a Tertiary Center in Abuja, Nigeria: A 3-Year Review

INTRODUCTION

Community-based delivery of antiretroviral therapy (ART) is an innovative approach that delivers HIV treatment services closer to the people, removing logistical barriers to clinic access, thereby improving ART uptake and retention in care. The United States Emergency Plan for AIDS Relief (PEPFAR) program in Nigeria involved community-based private sector pharmacies to expand uptake of ART. We aimed at evaluating the effectiveness of this innovation by comparing the CD4 cell count, weight and viral load of stable HIV patients before and after they were devolved to community pharmacies.

METHODOLOGY

This study was a facility-based retrospective study that analysed the data of HIV patients accessing care at the University of Abuja Teaching Hospital (UATH) Gwagwalada, Abuja, who were devolved to community pharmacies from June 2018 to May 2021. We compared their mean CD4 cell count, weight and viral load before they were devolved and 1 year after devolvement.

RESULTS

A total of 171 patients who met the eligibility criteria were devolved to community pharmacies during the study period. Majority (67.3%) of the patients were females. The age range was 24 years to 72 years with a median age of 42.8 years [inter-quartile range (IQR) 32, 62]. Their mean CD4 cell count (p=0.001) and weight (p=0.006) were higher after devolvement to community pharmacies compared to when they were at the clinic. They all maintained viral suppression after devolvement.

CONCLUSION

ART refill through community pharmacies is effective in maintaining viral suppression in stable HIV patients and may lead to increase in CD4 cell count and weight.

Prospective observational study of the challenges in diagnosing common neonatal conditions in Nigeria and Kenya

OBJECTIVES

Accurate and timely diagnosis of common neonatal conditions is crucial for reducing neonatal deaths. In low/middle-income countries with limited resources, there is sparse information on how neonatal diagnoses are made. The aim of this study was to describe the diagnostic criteria used for common conditions in neonatal units (NNUs) in Nigeria and Kenya.

DESIGN

Prospective observational study. Standard case report forms for suspected sepsis, respiratory disorders, birth asphyxia and abdominal conditions were co-developed by the Neonatal Nutrition Network (https://www.lstmed.ac.uk/nnu) collaborators. Clinicians completed forms for all admissions to their NNUs. Key data were displayed using heatmaps.

SETTING

Five NNUs in Nigeria and two in Kenya comprising the Neonatal Nutrition Network.

PARTICIPANTS

2851 neonates, which included all neonates admitted to the seven NNUs over a 6-month period.

RESULTS

1230 (43.1%) neonates had suspected sepsis, 874 (30.6%) respiratory conditions, 587 (20.6%) birth asphyxia and 71 (2.5%) abdominal conditions. For all conditions and across all NNUs, clinical criteria were used consistently with sparse use of laboratory and radiological criteria.

CONCLUSION

Our findings highlight the reliance on clinical criteria and extremely limited use of diagnostic technologies for common conditions in NNUs in sub-Saharan Africa. This has implications for the management of neonatal conditions which often have overlapping clinical features. Strategies for implementation of diagnostic pathways and investment in affordable and sustainable diagnostics are needed to improve care for these vulnerable infants.

Enteral Feeding Practices for Very Preterm and Very Low Birth Weight Infants in Nigeria and Kenya

Background

Optimizing nutrition in very preterm (28-32 weeks gestation) and very low birth weight (VLBW; 1,000 g to <1,500 g) infants has potential to improve their survival, growth, and long-term health outcomes.

Aim

To assess feeding practices in Nigeria and Kenya for very preterm and VLBW newborn infants.

Methods

This was a cross-sectional study where convenience sampling was used. A standard questionnaire was sent to doctors working in neonatal units in Nigeria and Kenya.

Results

Of 50 respondents, 37 (74.0%) were from Nigeria and 13 (26.0%) from Kenya. All initiated enteral feeds with breastmilk, with 24 (48.0%) initiating within 24 h. Only 28 (56.0%) used written feeding guidelines. Starting volumes ranged between 10 and 80 ml/kg/day. Median volume advancement of feeds was 20 ml/kg/day (IQR 10-20) with infants reaching full feeds in 8 days (IQR 6-12). 26 (52.0%) of the units fed the infants 2 hourly. Breastmilk fortification was practiced in 7 (14.0%) units, while folate, iron, calcium, and phosphorus were prescribed in 42 (84.0%), 36 (72.0%), 22 (44.0%), 5 (10.0%) of these units, respectively. No unit had access to donor breastmilk, and only 18 (36.0%) had storage facilities for expressed breastmilk. Twelve (24.0%) used wet nurses whilst 30 (60.0%) used formula feeds.

Conclusion

Feeding practices for very preterm and VLBW infants vary widely within Nigeria and Kenya, likely because of lack of locally generated evidence. High quality research that informs the feeding of these infants in the context of limited human resources, technology, and consumables, is urgently needed.

An open label, randomised controlled trial of rifapentine versus rifampicin based short course regimens for the treatment of latent tuberculosis in England: the HALT LTBI pilot study

BACKGROUND

Ending the global tuberculosis (TB) epidemic requires a focus on treating individuals with latent TB infection (LTBI) to prevent future cases. Promising trials of shorter regimens have shown them to be effective as preventative TB treatment, however there is a paucity of data on self-administered treatment completion rates. This pilot trial assessed treatment completion, adherence, safety and the feasibility of treating LTBI in the UK using a weekly rifapentine and isoniazid regimen versus daily rifampicin and isoniazid, both self-administered for 12 weeks.

METHODS

An open label, randomised, multi-site pilot trial was conducted in London, UK, between March 2015 and January 2017. Adults between 16 and 65 years with LTBI at two TB clinics who were eligible for and agreed to preventative therapy were consented and randomised 1:1 to receive either a weekly combination of rifapentine/isoniazid ('intervention') or a daily combination of rifampicin/isoniazid ('standard'), with both regimens taken for twelve weeks; treatment was self-administered in both arms. The primary outcome, completion of treatment, was self-reported, defined as taking more than 90% of prescribed doses and corroborated by pill counts and urine testing. Adverse events were recorded.

RESULTS

Fifty-two patients were successfully enrolled. In the intervention arm 21 of 27 patients completed treatment (77.8, 95% confidence interval [CI] 57.7-91.4), compared with 19 of 25 (76.0%, CI 54.9-90.6) in the standard of care arm. There was a similar adverse effect profile between the two arms.

CONCLUSION

In this pilot trial, treatment completion was comparable between the weekly rifapentine/isoniazid and the daily rifampicin/isoniazid regimens. Additionally, the adverse event profile was similar between the two arms. We conclude that it is safe and feasible to undertake a fully powered trial to determine whether self-administered weekly treatment is superior/non-inferior compared to current treatment.

TRIAL REGISTRATION

The trial was funded by the NIHR, UK and registered with ISRCTN ( 26/02/2013-No.04379941 ).

Burden of disease and risk factors for mortality amongst hospitalized newborns in Nigeria and Kenya

OBJECTIVE

To describe the patient population, priority diseases and outcomes in newborns admitted <48 hours old to neonatal units in both Kenya and Nigeria.

STUDY DESIGN

In a network of seven secondary and tertiary level neonatal units in Nigeria and Kenya, we captured anonymised data on all admissions <48 hours of age over a 6-month period.

RESULTS

2280 newborns were admitted. Mean birthweight was 2.3 kg (SD 0.9); 57.0% (1214/2128) infants were low birthweight (LBW; <2.5kg) and 22.6% (480/2128) were very LBW (VLBW; <1.5 kg). Median gestation was 36 weeks (interquartile range 32, 39) and 21.6% (483/2236) infants were very preterm (gestation <32 weeks). The most common morbidities were jaundice (987/2262, 43.6%), suspected sepsis (955/2280, 41.9%), respiratory conditions (817/2280, 35.8%) and birth asphyxia (547/2280, 24.0%). 18.7% (423/2262) newborns died; mortality was very high amongst VLBW (222/472, 47%) and very preterm infants (197/483, 40.8%). Factors independently associated with mortality were gestation <28 weeks (adjusted odds ratio 11.58; 95% confidence interval 4.73-28.39), VLBW (6.92; 4.06-11.79), congenital anomaly (4.93; 2.42-10.05), abdominal condition (2.86; 1.40-5.83), birth asphyxia (2.44; 1.52-3.92), respiratory condition (1.46; 1.08-2.28) and maternal antibiotics within 24 hours before or after birth (1.91; 1.28-2.85). Mortality was reduced if mothers received a partial (0.51; 0.28-0.93) or full treatment course (0.44; 0.21-0.92) of dexamethasone before preterm delivery.

CONCLUSION

Greater efforts are needed to address the very high burden of illnesses and mortality in hospitalized newborns in sub-Saharan Africa. Interventions need to address priority issues during pregnancy and delivery as well as in the newborn.

Completeness of TB notification in Portugal, 2015: an inventory and capture-recapture study

BACKGROUND: Despite the steady decline in the last few decades, Portugal remains the Western European country with the highest TB notification rates. The aim of this study was to estimate the completeness of notification to the National Tuberculosis Programme (NTP) Surveillance System (SVIG-TB) in 2015.METHODS: We implemented an inventory study and a three-source log-linear capture-recapture analysis using two additional data sources that were deterministic and probabilistically linked: the national notifiable diseases surveillance system (Sistema Nacional de Vigilância Epidemiológica SINAVE) and the national hospital discharge database (Grupos de Diagnósticos Homogéneos GDH).RESULTS: We identified 2328 unique probable/confirmed TB cases across the three data sources. We found a positive dependency between SVIG-TB and SINAVE (incidence rate ratio IRR 8.9, 95%CI 6.6-12.0) and between GDH and SINAVE (IRR 2.6, 95%CI 2.0-3.4). After adjusting for these dependencies, we estimated that 266 cases (95%CI 198-358) were not reported, indicating a notification (to SVIG-TB) completeness rate of 77.0%.CONCLUSION: True incidence rate of TB in Portugal in 2015 could have been as high as 26.1 per 100 000. This could be an overestimation because of false-positive cases recorded in both SINAVE and GDH or on a smaller scale, false non-matches. Studies aimed at validating potentially false-positive cases should be implemented to address these limitations.

Mobile-based and open-source infectious disease surveillance and outbreak management in Tanzania

Introduction

The PANDORA-ID-NET consortium aims to build capacity for effective outbreak response in sub-Saharan Africa. Part of this mission is to develop a real-time data sharing platform for disease outbreaks that leverages centralised data management and uses mobile technologies for data gathering and feedback. We have committed to using open-source technologies, so that the platform can be deployed on regional IT infrastructure and further developed by local staff, and collected data can be stored and processed in the region of origin. This abstract aims to describe how we identified a state of the art open-source system that fulfils these criteria, and the process of how we are extending it to function within the current infectious disease control framework in Tanzania, under our partnership with the Ifakara Health Institute (IHI).

Methods

To find state of the art open-source systems matching our criteria, we performed a rapid review of the literature. We screened 1022 articles and found 15 candidate systems, out of which only SORMAS satisfied the criteria. SORMAS was developed jointly by the Helmholtz Centre for Infection Research (HZI) and the Nigeria CDC, and was modeled on Nigeria's successful response to the Ebola outbreak. The system can be used for case management, contact tracing, surveillance, and laboratory sample management. Data is collected and synchronised using Android mobile devices (both online and offline) and data aggregation and analysis are performed in real-time via a web application

Results

Having chosen SORMAS, we established a collaboration between the SORMAS developer team and the PANDORA team. IHI are guiding ongoing work on adapting SORMAS to the Tanzanian health facility geography and the country's case definition guidelines for notifiable diseases.

Conclusions

Once adapted for Tanzania, SORMAS will fill an unoccupied niche in infectious disease control, improving the quality of collected case data and enabling better outbreak response

Key messages

A state of the art, mobile-based, open-source outbreak management and infectious disease surveillance system (SORMAS) is being deployed in Tanzania. We outline our experience with piloting SORMAS in Tanzania, building on the experience of our Nigerian and German partners, who rolled out this system nationally in Nigeria and other African countries.

Protocol for a cluster randomised control trial evaluating the efficacy and safety of treatment for latent tuberculosis infection in recent migrants within primary care: the CATAPuLT trial

Background

The identification and treatment of LTBI is a key component of the WHO’s strategy to eliminate TB. Recent migrants from high TB-incidence countries are recognised to be at risk TB reactivation, and many high-income countries have focused on LTBI screening and treatment programmes for this group. However, migrants are the group least likely to complete the LTBI cascade-of-care. This pragmatic cluster-randomised, parallel group, superiority trial investigates whether a model of care based entirely within a community setting (primary care) will improve treatment completion compared with treatment in specialist TB services (secondary care).

Methods

The CATAPuLT trial (Completion and Acceptability of Treatment Across Primary Care and the community for Latent Tuberculosis) randomised 34 general practices in London, England, to evaluate the efficacy and safety of treatment for LBTI in recent migrants within primary care. GP practices were randomised to either provide management for LTBI entirely within primary care (GPs and community pharmacists) or to refer patients to secondary care. The target recruitment number for individuals is 576. The primary outcome is treatment completion (defined as taking at least 90% of antibiotic doses). The secondary outcomes assess adherence, acceptance of treatment, the incidence of adverse effects including drug-induced liver injury, the rates of active TB, patient satisfaction and cost-effectiveness of LTBI treatment. This protocol adheres to the SPIRIT Checklist.

Discussion

The CATAPuLT trial seeks to provide implementation research evidence for a patient-centred intervention to improve treatment completion for LTBI amongst recent migrants to the UK.

Trial registration

NCT03069807, March 2017, registered retrospectively.

Tuberculosis infection and disease in people living with HIV in countries with low tuberculosis incidence

In countries with low tuberculosis (TB) incidence, TB is concentrated in vulnerable populations, including people living with the human immunodeficiency virus (PLHIV), who have a substantially greater risk of TB than people without HIV. We searched PubMed, EMBASE and Web of Science for studies evaluating the risk factors for latent tuberculous infection (LTBI) or active TB in PLHIV in countries with TB incidence 10 per 100 000 population. Due to the number of risk factors evaluated and heterogeneity in study designs, we present summary data and a narrative synthesis. We included 45 studies: 17 reported data on the risk factors for LTBI and 32 on active TB. Black, Asian or Hispanic ethnicity, birth or long-term residence in a country with high TB incidence, and HIV acquisition via injecting drug use (IDU) or heterosexual sex were strong predictors of both LTBI and active TB. History of contact, a greater degree of immunosuppression at diagnosis or higher viral load increased the TB risk. Early HIV diagnosis to allow timely initiation of antiretroviral therapy is essential for the prevention of TB in PLHIV. Screening and treating PLHIV for LTBI to reduce the risk of progression to active TB disease should also be considered to further reduce the burden of active TB in low TB incidence settings. Research to support the expansion of TB and HIV prevention and treatment globally is essential to eliminate TB in low-incidence settings.

Accuracy of an automated system for tuberculosis detection on chest radiographs in high-risk screening

SETTING:

Tuberculosis (TB) screening programmes can be optimised by reducing the number of chest radiographs (CXRs) requiring interpretation by human experts.

OBJECTIVE:

To evaluate the performance of computerised detection software in triaging CXRs in a high-throughput digital mobile TB screening programme.

DESIGN:

A retrospective evaluation of the software was performed on a database of 38 961 postero-anterior CXRs from unique individuals seen between 2005 and 2010, 87 of whom were diagnosed with TB. The software generated a TB likelihood score for each CXR. This score was compared with a reference standard for notified active pulmonary TB using receiver operating characteristic (ROC) curve and localisation ROC (LROC) curve analyses.

RESULTS:

On ROC curve analysis, software specificity was 55.71% (95%CI 55.21–56.20) and negative predictive value was 99.98% (95%CI 99.95–99.99), at a sensitivity of 95%. The area under the ROC curve was 0.90 (95%CI 0.86–0.93). Results of the LROC curve analysis were similar.

CONCLUSION:

The software could identify more than half of the normal images in a TB screening setting while maintaining high sensitivity, and may therefore be used for triage.

Active case finding and treatment adherence in risk groups in the tuberculosis pre-elimination era

Vulnerable populations, including homeless persons, high-risk drug and alcohol users, prison inmates and other marginalised populations, contribute a disproportionate burden of tuberculosis (TB) cases in low-incidence settings. Drivers of this disease burden include an increased risk of both TB transmission in congregate settings, and progression from infection to active disease. Late diagnosis and poor treatment completion further propagate the epidemic and fuel the acquisition of drug resistance. These groups are therefore a major priority for TB control programmes in low-incidence settings. Targeted strategies include active case finding (ACF) initiatives and interventions to improve treatment completion, both of which should be tailored to local populations. ACF usually deploys mobile X-ray unit screening, which allows sensitive, high-throughput screening with immediate availability of results. Such initiatives have been found to be effective and cost-effective, and associated with reductions in proxy measures of transmission in hard-to-reach groups. The addition of point-of-care molecular diagnostics and automated X-ray readers may further streamline the screening pathway. There is little evidence to support interventions to improve adherence among these risk groups. Such approaches include enhanced case management and directly observed treatment, while video-observed therapy (currently under evaluation) appears to be a promising tool for the future. Integrating outreach services to include both case detection and case-management interventions that share a resource infrastructure may allow cost-effectiveness to be maximised. Integrating screening and treatment for other diseases that are prevalent among targeted risk groups into TB outreach interventions may further improve cost-effectiveness. This article reviews the existing literature, and highlights priorities for further research.

Public health outcome of Tuberculosis Cluster Investigations, England 2010-2013

OBJECTIVES

Tuberculosis (TB) is a serious re-emergent public health problem in the UK. In response to rising case incidence a National TB Strain-Typing Service based on molecular strain-typing was established. This facilitates early detection and investigation of clusters, targeted public health action, and prevention of further transmission. We review the added public health value of investigating molecular TB strain-typed (ST) clusters.

METHODS

A structured questionnaire for each ST cluster investigated in England between 1 January 2010 and 30 June 2013 was completed. Questions related to epidemiological links and public health action and the perceived benefits of ST cluster investigation.

RESULTS

There were 278 ST cluster investigations (CIs) involving 1882 TB cases. Cluster size ranged from 2 to 92. CIs identified new epidemiological links in 36% of clusters; in 18% STs were discordant refuting transmission thought to have occurred. Additional public health action was taken following 23% of CI.

CONCLUSIONS

We found positive benefits of TB molecular ST and CI, in identifying new epidemiological links between cases and taking public health action and in refuting transmission and saving resources. This needs to be translated to a decrease in transmission to provide evidence of public health value in this low prevalence high resource setting.

Development of a data collection and management system in West Africa: challenges and sustainability

BACKGROUND

Developing and sustaining a data collection and management system (DCMS) is difficult in malaria-endemic countries because of limitations in internet bandwidth, computer resources and numbers of trained personnel. The premise of this paper is that development of a DCMS in West Africa was a critically important outcome of the West African International Centers of Excellence for Malaria Research. The purposes of this paper are to make that information available to other investigators and to encourage the linkage of DCMSs to international research and Ministry of Health data systems and repositories.

METHODS

We designed and implemented a DCMS to link study sites in Mali, Senegal and The Gambia. This system was based on case report forms for epidemiologic, entomologic, clinical and laboratory aspects of plasmodial infection and malarial disease for a longitudinal cohort study and included on-site training for Principal Investigators and Data Managers. Based on this experience, we propose guidelines for the design and sustainability of DCMSs in environments with limited resources and personnel.

RESULTS

From 2012 to 2017, we performed biannual thick smear surveys for plasmodial infection, mosquito collections for anopheline biting rates and sporozoite rates and year-round passive case detection for malarial disease in four longitudinal cohorts with 7708 individuals and 918 households in Senegal, The Gambia and Mali. Major challenges included the development of uniform definitions and reporting, assessment of data entry error rates, unstable and limited internet access and software and technology maintenance. Strengths included entomologic collections linked to longitudinal cohort studies, on-site data centres and a cloud-based data repository.

CONCLUSIONS

At a time when research on diseases of poverty in low and middle-income countries is a global priority, the resources available to ensure accurate data collection and the electronic availability of those data remain severely limited. Based on our experience, we suggest the development of a regional DCMS. This approach is more economical than separate data centres and has the potential to improve data quality by encouraging shared case definitions, data validation strategies and analytic approaches including the molecular analysis of treatment successes and failures.

Discordance in latent tuberculosis (TB) test results in patients with end-stage renal disease

OBJECTIVES

This natural experiment was designed to assess the impact of exposure to an active case of tuberculosis (TB) on a group of immunosuppressed individuals, with end-stage renal disease over an extended follow-up.

STUDY DESIGN

Close contacts of people with sputum smear-positive Mycobacterium tuberculosis are at high risk of infection, particularly immunosuppressed individuals. An infectious TB healthcare worker worked in a renal dialysis unit for a month before diagnosis, with 104 renal dialysis patients, was exposed for ≥8 h.

METHODS

Patients were informed and invited for screening 8-10 weeks postexposure. They either underwent standard two-step assessment with tuberculin skin test (TST) and QuantiFERON^®-TB Gold (Cellestis GmbH; QFN) interferon-gamma release assay (IGRA) or after consent, enrolled in a study where these two tests were performed simultaneously with T-SPOT^®-TB (Oxford Immunotec Ltd; TSPOT). Patients within the study were followed up for 2 years from exposure, with QFN and TSPOT repeated at months 3 and 6 from the first testing.

RESULTS

Of 104 exposed individuals, 75 enrolled in the study. There was a high degree of discordance among QFN, TSPOT and TST. This was seen at both the first time point and also over time in subjects who were retested. No patients had active TB at the baseline testing. None received treatment for latent TB infection. Over the following 2 years, no one developed TB disease.

CONCLUSION

This study suggests that there is a low risk of progression to active TB in low-incidence countries even in high-risk groups. This plus the degree of the test result discordance emphasises the complexities of managing TB in such settings as it is unclear which of these tests, if any, provides the best diagnostic accuracy.

Assessing uncertainty in the burden of hepatitis C virus: Comparison of estimated disease burden and treatment costs in the UK

Hepatitis C virus (HCV) is a major and growing public health concern. We need to know the expected health burden and treatment cost, and understand uncertainty in those estimates, to inform policymaking and future research. Two models that have been important in informing treatment guidelines and assessments of HCV burden were compared by simulating cohorts of individuals with chronic HCV infection initially aged 20, 35 and 50 years. One model predicts that health losses (measured in quality-adjusted life-years [QALYs]) and treatment costs decrease with increasing initial age of the patients, whilst the other model predicts that below 40 years, costs increase and QALY losses change little with age, and above 40 years, they decline with increasing age. Average per-patient costs differ between the models by up to 38%, depending on the patients' initial age. One model predicts double the total number, and triple the peak annual incidence, of liver transplants compared to the other model. One model predicts 55%-314% more deaths than the other, depending on the patients' initial age. The main sources of difference between the models are estimated progression rates between disease states and rates of health service utilization associated with different disease states and, in particular, the age dependency of these parameters. We conclude that decision-makers need to be aware that uncertainties in the health burden and economic cost of HCV disease have important consequences for predictions of future need for care and cost-effectiveness of interventions to avert HCV transmission, and further quantification is required to inform decisions.

Measuring ventilation and modelling M. tuberculosis transmission in indoor congregate settings, rural KwaZulu-Natal

SETTING: Molecular epidemiology suggests that most Mycobacterium tuberculosis transmission in high-burden settings occurs outside the home.

OBJECTIVE: To estimate the risk of M. tuberculosis transmission inside public buildings in a high TB burden community in KwaZulu-Natal, South Africa.

DESIGN: Carbon dioxide (CO₂) sensors were placed inside eight public buildings. Measurements were used with observations of occupancy to estimate infection risk using an adaptation of the Wells-Riley equation. Ventilation modelling using CONTAM was used to examine the impact of low-cost retrofits on transmission in a health clinic.

RESULTS: Measurements indicate that infection risk in the church, classroom and clinic waiting room would be high with typical ventilation, occupancy levels and visit durations. For example, we estimated that health care workers in a clinic waiting room had a 16.9–24.5% annual risk of M. tuberculosis infection. Modelling results indicate that the simple addition of two new windows allowing for cross-ventilation, at a cost of US$330, would reduce the annual risk to health care workers by 57%.

CONCLUSIONS: Results indicate that public buildings in this community have a range of ventilation and occupancy characteristics that may influence transmission risks. Simple retrofits may result in dramatic reductions in M. tuberculosis transmission, and intervention studies should therefore be considered.

Medical Informatics in Medical Research

Objectives: Computers are widely used for data management in clinical trials in the developed coutries, unlike in developing countries. Dependable systems are vital for data management, and medical decision making in clinical research. Monitoring and evaluation of data management is critical.

In this paper we describe database structures and procedures of systems used to implement, coordinate, and sustain data management in Africa. We outline major lessons, challenges and successes achieved, and recommendations to improve medical informatics application in biomedical research in sub-Saharan Africa.

Methods: A consortium of experienced research units at five sites in Africa in studying children with disease formed a new clinical trials network, Severe Malaria in African Children. In December 2000, the network introduced an observational study involving these hospital-based sites. After prototyping, relational database management systems were implemented for data entry and verification, data submission and quality assurance monitoring.

Results: Between 2000 and 2005, 25,858 patients were enrolled. Failure to meet data submission deadline and data entry errors correlated positively (correlation coefficient, r = 0.82), with more errors occurring when data was submitted late. Data submission lateness correlated inversely with hospital admissions (r = –0.62).

Conclusions: Developing and sustaining dependable DBMS, ongoing modifications to optimize data management is crucial for clinical studies. Monitoring and communication systems are vital in multi-center networks for good data management. Data timeliness is associated with data quality and hospital admissions.

Treatment regimens for rifampicin-resistant tuberculosis: highlighting a research gap

Treatment guidance for non-multidrug-resistant (MDR) rifampicin-resistant (RMP-R) tuberculosis (TB) is variable. We aimed to undertake a systematic review and meta-analysis of the randomised controlled trial (RCT) data behind such guidelines to identify the most efficacious treatment regimens. Ovid MEDLINE, the Web of Science and EMBASE were mined using search terms for TB, drug therapy and RCTs. Despite 12 604 records being retrieved, only three studies reported treatment outcomes by regimen for patients with non-MDR RMP-R disease, preventing meta-analysis. Our systematic review highlights a substantial gap in the literature regarding evidence-based treatment regimens for RMP-R TB.

Capacity strengthening through pre-migration tuberculosis screening programmes: IRHWG experiences

Effective tuberculosis (TB) prevention and care for migrants requires population health-based approaches that treat the relationship between migration and health as a progressive, interactive process influenced by many variables and addressed as far upstream in the process as possible. By including capacity building in source countries, pre-migration medical screening has the potential to become an integral component of public health promotion, as well as infection and disease prevention, in migrant-receiving nations, while simultaneously increasing capabilities in countries of origin. This article describes the collaborative experiences of five countries (Australia, Canada, New Zealand, United Kingdom and the United States of America, members of the Immigration and Refugee Health Working Group [IRHWG]), with similar pre-migration screening programmes for TB that are mandated. Qualitative examples of capacity building through IRHWG programmes are provided. Combined, the IRHWG member countries screen approximately 2 million persons overseas every year. Large-scale pre-entry screening programmes undertaken by IRHWG countries require building additional capacity for health care providers, radiology facilities and laboratories. This has resulted in significant improvements in laboratory and treatment capacity, providing availability of these facilities for national public health programmes. As long as global health disparities and disease prevalence differentials exist, national public health programmes and policies in migrant-receiving nations will continue to be challenged to manage the diseases prevalent in these migrating populations. National TB programmes and regulatory systems alone will not be able to achieve TB elimination. The management of health issues resulting from population mobility will require integration of national and global health initiatives which, as demonstrated here, can be supported through the capacity-building endeavours of pre-migration screening programmes.

Tuberculosis treatment outcomes among disadvantaged patients in India

Setting: Urban slums and poor rural areas in India, 2012-2014. Objective: To describe the characteristics of tuberculosis (TB) patients enrolled in treatment through Operation ASHA, a non-governmental organisation serving disadvantaged populations in India, and to identify risk factors for unfavourable treatment outcomes. Design: This was a retrospective cohort study. Patient characteristics were assessed for their relationship with treatment outcomes using mixed effects logistic regression, adjusting for clustering by treatment centre and Indian state. Outcomes were considered favourable (cured/treatment completed) or unfavourable (treatment failure, loss to follow-up, death, switch to multidrug-resistant TB treatment, transfer out). Results: Of 8415 patients, 7148 (84.9%) had a favourable outcome. On multivariable analysis, unfavourable outcomes were more common among men (OR 1.31, 95%CI 1.15-1.51), older patients (OR 1.12, 95%CI 1.04-1.21) and previously treated patients (OR 2.05, 95%CI 1.79-2.36). Compared to pulmonary smear-negative patients, those with extra-pulmonary disease were less likely to have unfavourable outcomes (OR 0.72, 95%CI 0.60-0.87), while smear-positive pulmonary patients were more likely to have unfavourable outcomes (OR 1.38, 95%CI 1.15-1.66 for low [scanty/1+] and OR 1.71, 95%CI 1.44-2.04 for high [2+/3+] positive smears). Conclusion: The treatment success rate within Operation ASHA is comparable to that reported nationally for India. Men, older patients, retreatment cases and smear-positive pulmonary TB patients may need additional interventions to ensure a favourable outcome.

Drug-resistant tuberculosis clinical trials: proposed core research definitions in adults

Drug-resistant tuberculosis (DR-TB) is a growing public health problem, and for the first time in decades, new drugs for the treatment of this disease have been developed. These new drugs have prompted strengthened efforts in DR-TB clinical trials research, and there are now multiple ongoing and planned DR-TB clinical trials. To facilitate comparability and maximise policy impact, a common set of core research definitions is needed, and this paper presents a core set of efficacy and safety definitions as well as other important considerations in DR-TB clinical trials work. To elaborate these definitions, a search of clinical trials registries, published manuscripts and conference proceedings was undertaken to identify groups conducting trials of new regimens for the treatment of DR-TB. Individuals from these groups developed the core set of definitions presented here. Further work is needed to validate and assess the utility of these definitions but they represent an important first step to ensure there is comparability in clinical trials on multidrug-resistant TB.

Plan Beta for tuberculosis: it's time to think seriously about poorly ventilated congregate settings

Globally, the rates of decline in tuberculosis (TB) incidence are disappointing, but in line with model predictions regarding the likely impact of the DOTS strategy. Here, we review evidence from basic epidemiology, molecular epidemiology and modelling, all of which suggest that, in high-burden settings, the majority of Mycobacterium tuberculosis transmission may occur in indoor congregate settings. We argue that mass environmental modifications in these places might have a significant impact on TB control and suggest a research agenda that might inform interventions of this nature. The necessary technology exists and, critically, implementation would not be dependent on health care workers who are in short supply in the communities worst affected by TB.

What are the most efficacious treatment regimens for isoniazid-resistant tuberculosis? A systematic review and network meta-analysis

Introduction

Consensus on the best treatment regimens for patients with isoniazid-resistant TB is limited; global treatment guidelines differ. We undertook a systematic review and meta-analysis using mixed-treatment comparisons methodology to provide an up-to-date summary of randomised controlled trials (RCTs) and relative regimen efficacy.

Methods

Ovid MEDLINE, the Web of Science and EMBASE were mined using search terms for TB, drug therapy and RCTs. Extracted data were inputted into fixed-effects and random-effects models. ORs for all possible network comparisons and hierarchical rankings for different regimens were obtained.

Results

12 604 records were retrieved and 118 remained postextraction, representing 59 studies—27 standalone and 32 with multiple papers. In comparison to a baseline category that included the WHO-recommended regimen for countries with high levels of isoniazid resistance (rifampicin-containing regimens using fewer than three effective drugs at 4 months, in which rifampicin was protected by another effective drug at 6 months, and rifampicin was taken for 6 months), extending the duration of rifampicin and increasing the number of effective drugs at 4 months lowered the odds of unfavourable outcomes (treatment failure or the lack of microbiological cure; relapse post-treatment; death due to TB) in a fixed-effects model (OR 0.31 (95% credible interval 0.12–0.81)). In a random-effects model all estimates crossed the null.

Conclusions

Our systematic review and network meta-analysis highlight a regimen category that may be more efficacious than the WHO population level recommendation, and identify knowledge gaps where data are sparse.

Systematic review registration number

PROSPERO CRD42014015025.

Non-falciparum malaria infections in pregnant women in West Africa

BACKGROUND

Non-Plasmodium falciparum malaria infections are found in many parts of sub-Saharan Africa but little is known about their importance in pregnancy.

METHODS

Blood samples were collected at first antenatal clinic attendance from 2526 women enrolled in a trial of intermittent screening and treatment of malaria in pregnancy (ISTp) versus intermittent preventive treatment (IPTp) conducted in Burkina Faso, The Gambia, Ghana and Mali. DNA was extracted from blood spots and tested for P. falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale using a nested PCR test. Risk factors for a non-falciparum malaria infection were investigated and the influence of these infections on the outcome of pregnancy was determined.

RESULTS

P. falciparum infection was detected frequently (overall prevalence by PCR: 38.8 %, [95 % CI 37.0, 40.8]), with a prevalence ranging from 10.8 % in The Gambia to 56.1 % in Ghana. Non-falciparum malaria infections were found only rarely (overall prevalence 1.39 % [95 % CI 1.00, 1.92]), ranging from 0.17 % in the Gambia to 3.81 % in Mali. Ten non-falciparum mono-infections and 25 mixed falciparum and non-falciparum infections were found. P. malariae was the most frequent non-falciparum infection identified; P. vivax was detected only in Mali. Only four of the non-falciparum mono-infections were detected by microscopy or rapid diagnostic test. Recruitment during the late rainy season and low socio-economic status were associated with an increased risk of non-falciparum malaria as well as falciparum malaria. The outcome of pregnancy did not differ between women with a non-falciparum malaria infection and those who were not infected with malaria at first ANC attendance.

CONCLUSIONS

Non-falciparum infections were infrequent in the populations studied, rarely detected when present as a mono-infection and unlikely to have had an important impact on the outcome of pregnancy in the communities studied due to the small number of women infected with non-falciparum parasites.

Seasonal variation in haematological and biochemical reference values for healthy young children in The Gambia

Background

Haematological and biochemistry reference values for children are important for interpreting clinical and research results however, differences in demography and environment poses a challenge when comparing results. The study defines reference intervals for haematological and biochemistry parameters and examines the effect of seasonality in malaria transmission.

Methods

Blood samples collected from clinically healthy children, aged 12–59 months, in two surveys during the dry and wet season in the Upper River region of The Gambia were processed and the data analysed to generate reference intervals based on the 2.5^th and 97.5^th percentiles of the data.

Results

Analysis was based on data from 1141 children with median age of 32 months. The mean values for the total white cell count and differentials; lymphocyte, monocyte and neutrophil decreased with increasing age, were lower in males and higher in the wet season survey. However, platelet values declined with age (p < 0.0001). There was no evidence of effect of gender on mean values of AST, ALT, lymphocytes, monocytes, platelets and haemoglobin.

Conclusion

Mean estimates for haematological and biochemistry reference intervals are affected by age and seasonality in the first five years of life. This consistency is important for harmonisation of reference values for clinical care and interpretation of trial results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-016-0545-6) contains supplementary material, which is available to authorized users.

A multi-perspective service evaluation exploring tuberculosis contact screening attendance among adults at a North London hospital

BACKGROUND

Non-attendance at TB contact screening clinics has been highlighted as a common phenomenon across a number of sites during recruitment to the PREDICT TB Study. This has obvious implications for the safety of patients, their communities and for NHS resources. The objective of this study was to explore why adults who have been in contact with TB do, and do not, attend their screening appointment, thereby allowing identification of interventions to reduce non-attendance.

METHODS

A multi-method approach was taken using 15 questionnaires with adults who attended for screening, 15 telephone questionnaires with adults who did not attend and in-depth interviews with 8 TB nurses. Interviews were coded to trace emerging descriptive themes, then refined through an iterative process of interpretation and recoding.

RESULTS

Findings from the questionnaires and interviews were categorized into three principle themes following analysis: awareness, hospital factors and leadership. These themes deconstruct the complex phenomena of patients' lack of attendance at this TB contact screening service.

CONCLUSION

Recommendations related to issues of leadership, outreach services, flexibility of clinic timing and awareness amongst both the local community and GPs were made.

A Non-Inferiority, Individually Randomized Trial of Intermittent Screening and Treatment versus Intermittent Preventive Treatment in the Control of Malaria in Pregnancy

BACKGROUND

The efficacy of intermittent preventive treatment for malaria with sulfadoxine-pyrimethamine (IPTp-SP) in pregnancy is threatened in parts of Africa by the emergence and spread of resistance to SP. Intermittent screening with a rapid diagnostic test (RDT) and treatment of positive women (ISTp) is an alternative approach.

METHODS AND FINDINGS

An open, individually randomized, non-inferiority trial of IPTp-SP versus ISTp was conducted in 5,354 primi- or secundigravidae in four West African countries with a low prevalence of resistance to SP (The Gambia, Mali, Burkina Faso and Ghana). Women in the IPTp-SP group received SP on two or three occasions whilst women in the ISTp group were screened two or three times with a RDT and treated if positive for malaria with artemether-lumefantrine (AL). ISTp-AL was non-inferior to IPTp-SP in preventing low birth weight (LBW), anemia and placental malaria, the primary trial endpoints. The prevalence of LBW was 15.1% and 15.6% in the IPTp-SP and ISTp-AL groups respectively (OR = 1.03 [95% CI: 0.88, 1.22]). The mean hemoglobin concentration at the last clinic attendance before delivery was 10.97g/dL and 10.94g/dL in the IPTp-SP and ISTp-AL groups respectively (mean difference: -0.03 g/dL [95% CI: -0.13, +0.06]). Active malaria infection of the placenta was found in 24.5% and in 24.2% of women in the IPTp-SP and ISTp-AL groups respectively (OR = 0.95 [95% CI 0.81, 1.12]). More women in the ISTp-AL than in the IPTp-SP group presented with malaria parasitemia between routine antenatal clinics (310 vs 182 episodes, rate difference: 49.4 per 1,000 pregnancies [95% CI 30.5, 68.3], but the number of hospital admissions for malaria was similar in the two groups.

CONCLUSIONS

Despite low levels of resistance to SP in the study areas, ISTp-AL performed as well as IPTp-SP. In the absence of an effective alternative medication to SP for IPTp, ISTp-AL is a potential alternative to IPTp in areas where SP resistance is high. It may also have a role in areas where malaria transmission is low and for the prevention of malaria in HIV positive women receiving cotrimoxazole prophylaxis in whom SP is contraindicated.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01084213 Pan African Clinical trials Registry PACT201202000272122.

The impact of genomics on public health practice

INTRODUCTION

Genomic science is developing rapidly, and engagement of public health professionals will be necessary to appraise new technologies and use them effectively.

SOURCES OF DATA

We use established domains of public health and draw on the literature and expert knowledge to illustrate how genomic technologies give rise to new applications.

AREAS OF AGREEMENT

Genomic technologies are useful in rare inherited disease, including population screening programmes, in health care and for surveillance, diagnosis and treatment of infectious disease.

AREAS OF CONTROVERSY

It is less clear when and how genetic susceptibility testing will be used for common chronic disease prevention or protection from environmental hazards.

GROWING POINTS

Developments in public health practice will be necessary to ensure rapid and effective implementation of genomic science.

AREAS TIMELY FOR DEVELOPING RESEARCH

Public health researchers should address how to accelerate the implementation of genomics for health benefit in developed and developing countries.

Effect of BCG vaccination against Mycobacterium tuberculosis infection in children: systematic review and meta-analysis

OBJECTIVES

To determine whether BCG vaccination protects against Mycobacterium tuberculosis infection as assessed by interferon γ release assays (IGRA) in children.

DESIGN

Systematic review and meta-analysis. Searches of electronic databases 1950 to November 2013, checking of reference lists, hand searching of journals, and contact with experts.

SETTING

Community congregate settings and households.

INCLUSION CRITERIA

Vaccinated and unvaccinated children aged under 16 with known recent exposure to patients with pulmonary tuberculosis. Children were screened for infection with M tuberculosis with interferon γ release assays.

DATA EXTRACTION

Study results relating to diagnostic accuracy were extracted and risk estimates were combined with random effects meta-analysis.

RESULTS

The primary analysis included 14 studies and 3855 participants. The estimated overall risk ratio was 0.81 (95% confidence interval 0.71 to 0.92), indicating a protective efficacy of 19% against infection among vaccinated children after exposure compared with unvaccinated children. The observed protection was similar when estimated with the two types of interferon γ release assays (ELISpot or QuantiFERON). Restriction of the analysis to the six studies (n=1745) with information on progression to active tuberculosis at the time of screening showed protection against infection of 27% (risk ratio 0.73, 0.61 to 0.87) compared with 71% (0.29, 0.15 to 0.58) against active tuberculosis. Among those infected, protection against progression to disease was 58% (0.42, 0.23 to 0.77).

CONCLUSIONS

BCG protects against M tuberculosis infection as well as progression from infection to disease.Trial registration PROSPERO registration No CRD42011001698 (www.crd.york.ac.uk/prospero/).

Systematic review and meta-analysis of the current evidence on the duration of protection by bacillus Calmette-Guérin vaccination against tuberculosis

BACKGROUND

Recent evidence suggests that the duration of protection by bacillus Calmette-Guérin (BCG) may exceed previous estimates with potential implications for estimating clinical and cost-efficacy.

OBJECTIVES

To estimate the protection and duration of protection provided by BCG vaccination against tuberculosis, explore how this protection changes with time since vaccination, and examine the reasons behind the variation in protection and the rate of waning of protection.

DATA SOURCES

Electronic databases including MEDLINE, Excerpta Medica Database (EMBASE), Cochrane Databases, NHS Economic Evaluation Database (NHS EED), Database of Abstracts of Reviews of Effects (DARE), Web of Knowledge, Biosciences Information Service (BIOSIS), Latin American and Caribbean Health Sciences Literature (LILACs), MEDCARIB Database, Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched from inception to May 2009. Index to Theses, System for Information on Grey Literature in Europe (SIGLE), Centre for Agricultural Bioscience International (CABI) Abstracts, Scopus, Article First, Academic Complete, Africa-Wide Information, Google Scholar, Global Health, British National Bibliography for Report Literature, and clinical trial registration websites were searched from inception to October 2009.

REVIEW METHODS

Electronic databases searches, screening of identified studies, data extraction and analysis were undertaken. Meta-analysis was used to present numerical and graphical summaries of clinical efficacy and efficacy by time since vaccination. Evidence of heterogeneity was assessed using the tau-squared statistic. Meta-regression allowed the investigation of observed heterogeneity. Factors investigated included BCG strain, latitude, stringency of pre-BCG vaccination tuberculin testing, age at vaccination, site of disease, study design and vulnerability to biases. Rate of waning of protection was estimated using the ratio of the measure of efficacy after 10 years compared with the efficacy in the first 10 years of a study.

RESULTS

Study selection. A total of 21,030 references were identified, providing data on 132 studies after abstract and full-text review. Efficacy. Protection against pulmonary tuberculosis in adults is variable, ranging from substantial protection in the UK MRC trial {rate ratio 0.22 [95% confidence interval (CI) 0.16 to 0.31]}, to absence of clinically important benefit, as in the large Chingleput trial [rate ratio 1.05 (95% CI 0.88 to 1.25)] and greater in latitudes further away from the equator. BCG vaccination efficacy was usually high, and varied little by form of disease (with higher protection against meningeal and miliary tuberculosis) or study design when BCG vaccination was given only to infants or to children after strict screening for tuberculin sensitivity. High levels of protection against death were observed from both trials and observational studies. The observed protective effect of BCG vaccination did not differ by the strain of BCG vaccine used in trials.

DURATION

Reviewed studies showed that BCG vaccination protects against pulmonary and extrapulmonary tuberculosis for up to 10 years. Most studies either did not follow up participants for long enough or had very few cases after 15 years. This should not be taken to indicate an absence of effect: five studies (one trial and four observational studies) provided evidence of measurable protection at least 15 years after vaccination. Efficacy declined with time. The rate of decline was variable, with faster decline in latitudes further from the equator and in situations where BCG vaccination was given to tuberculin-sensitive participants after stringent tuberculin testing.

LIMITATIONS

The main limitation of this review relates to quality of included trials, most of which were conducted before current standards for reporting were formulated. In addition, data were lacking in some areas and the review had to rely on evidence from observational studies.

CONCLUSIONS

BCG vaccination protection against tuberculosis varies between populations, to an extent that cannot be attributed to chance alone. Failure to exclude those already sensitised to mycobacteria and study latitude closer to the equator were associated with lower efficacy. These factors explained most of the observed variation. There is good evidence that BCG vaccination protection declines with time and that protection can last for up to 10 years. Data on protection beyond 15 years are limited; however, a small number of trials and observational studies suggest that BCG vaccination may protect for longer. Further studies are required to investigate the duration of protection by BCG vaccination.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.