Impact of nutritional status on vaccine-induced immunity in children living in South Africa: Investigating the B-cell repertoire and metabolic hormones

OBJECTIVES

We explored the role of metabolic hormones and the B-cell repertoire in the association between nutritional status and vaccine responses.

METHODS

In this prospective cohort study, nested within a larger randomized open-label trial, 211 South African children received two doses of measles vaccine and two or three doses of pneumococcal conjugate vaccine (PCV). Metabolic markers (leptin, ghrelin and adiponectin) and distribution of B-cell subsets (n = 106) were assessed at 18 months of age.

RESULTS

Children with a weight-for-height z-score (WHZ) ≤ -1 standard deviation (SD) at booster vaccination had a decreased mean serotype-specific PCV IgG response compared with those with WHZ > -1 and <+1 SD or WHZ ≥ +1 SD at 9 months post-booster (18 months of age). (Naive) pre-germinal center B-cells were associated with pneumococcal antibody decay between one to nine months post-booster. Predictive performance of elastic net models for the combined effect of B-cell subsets, metabolic hormones and nutritional status (in addition to age, sex, and randomization group) on measles and PCV vaccine response had an average area under the receiver operating curve of 0.9 and 0.7, respectively.

CONCLUSIONS

The combined effect of B-cell subsets, metabolic hormones and nutritional status correlated well with the vaccination response for measles and most PCV serotypes.

CLINICALTRIALS

gov registration of parent studies: NCT02943902 and NCT03330171.

Predictors of TB disease in HIV-exposed children from Southern Africa

BACKGROUND: P1041 was a randomised, placebo-controlled isoniazid prophylaxis trial in South Africa. We studied predictors for TB in HIV-exposed children participating in the P1041 trial.METHODS: We included data from entry until Week 108. Predictors considered were type of housing, overcrowding, age, sex, ethnicity, tobacco exposure, weight-for-age percentile Z-score (WAZ), CD4%, viral load (VL), antiretroviral therapy (ART) and number of household smokers.RESULTS: Of 543 HIV-positive (HIV+) and 808 HIV-exposed uninfected (HEU) infants at entry, median age was 96 days (interquartile range: 92-105). Of 1,351 caregivers, 125 (9%) had a smoking history, and 62/1,351 reported current smoking. In 594/1,351 (44%) households, there was at least one smoker. Smoking caregivers consumed 1-5 cigarettes daily. In the HIV+ cohort, significant baseline TB predictors after adjusting covariates were as follows: WAZ (adjusted hazard ratio [aHR] 0.76, P = 0.002) and log10 HIV RNA copies/ml (aHR 1.50, P = 0.009). Higher CD4% (aHR 0.88, P = 0.002) and ART (aHR 0.50, P = 0.006) were protective. In the HEU cohort, smoking exposure was associated with reduced TB-free survival on univariate analysis, but not after adjustment in the multivariate model.CONCLUSION: Low WAZ and high VL were strong predictors of TB disease or death. Rising CD4 percentage and being on ART were protective in the HIV+ cohort.

In-hospital mortality risk stratification in children aged under 5 years with pneumonia with or without pulse oximetry: A secondary analysis of the Pneumonia REsearch Partnership to Assess WHO REcommendations (PREPARE) dataset

OBJECTIVES

We determined the pulse oximetry benefit in pediatric pneumonia mortality risk stratification and chest-indrawing pneumonia in-hospital mortality risk factors.

METHODS

We report the characteristics and in-hospital pneumonia-related mortality of children aged 2-59 months who were included in the Pneumonia Research Partnership to Assess WHO Recommendations dataset. We developed multivariable logistic regression models of chest-indrawing pneumonia to identify mortality risk factors.

RESULTS

Among 285,839 children, 164,244 (57.5%) from hospital-based studies were included. Pneumonia case fatality risk (CFR) without pulse oximetry measurement was higher than with measurement (5.8%, 95% confidence interval [CI] 5.6-5.9% vs 2.1%, 95% CI 1.9-2.4%). One in five children with chest-indrawing pneumonia was hypoxemic (19.7%, 95% CI 19.0-20.4%), and the hypoxemic CFR was 10.3% (95% CI 9.1-11.5%). Other mortality risk factors were younger age (either 2-5 months [adjusted odds ratio (aOR) 9.94, 95% CI 6.67-14.84] or 6-11 months [aOR 2.67, 95% CI 1.71-4.16]), moderate malnutrition (aOR 2.41, 95% CI 1.87-3.09), and female sex (aOR 1.82, 95% CI 1.43-2.32).

CONCLUSION

Children with a pulse oximetry measurement had a lower CFR. Many children hospitalized with chest-indrawing pneumonia were hypoxemic and one in 10 died. Young age and moderate malnutrition were risk factors for in-hospital chest-indrawing pneumonia-related mortality. Pulse oximetry should be integrated in pneumonia hospital care for children under 5 years.

Assembling a global database of child pneumonia studies to inform WHO pneumonia management algorithm: Methodology and applications

Background

The existing World Health Organization (WHO) pneumonia case management guidelines rely on clinical symptoms and signs for identifying, classifying, and treating pneumonia in children up to 5 years old. We aimed to collate an individual patient-level data set from large, high-quality pre-existing studies on pneumonia in children to identify a set of signs and symptoms with greater validity in the diagnosis, prognosis, and possible treatment of childhood pneumonia for the improvement of current pneumonia case management guidelines.

Methods

Using data from a published systematic review and expert knowledge, we identified studies meeting our eligibility criteria and invited investigators to share individual-level patient data. We collected data on demographic information, general medical history, and current illness episode, including history, clinical presentation, chest radiograph findings when available, treatment, and outcome. Data were gathered separately from hospital-based and community-based cases. We performed a narrative synthesis to describe the final data set.

Results

Forty-one separate data sets were included in the Pneumonia Research Partnership to Assess WHO Recommendations (PREPARE) database, 26 of which were hospital-based and 15 were community-based. The PREPARE database includes 285 839 children with pneumonia (244 323 in the hospital and 41 516 in the community), with detailed descriptions of clinical presentation, clinical progression, and outcome. Of 9185 pneumonia-related deaths, 6836 (74%) occurred in children <1 year of age and 1317 (14%) in children aged 1-2 years. Of the 285 839 episodes, 280 998 occurred in children 0-59 months old, of which 129 584 (46%) were 2-11 months of age and 152 730 (54%) were males.

Conclusions

This data set could identify an improved specific, sensitive set of criteria for diagnosing clinical pneumonia and help identify sick children in need of referral to a higher level of care or a change of therapy. Field studies could be designed based on insights from PREPARE analyses to validate a potential revised pneumonia algorithm. The PREPARE methodology can also act as a model for disease database assembly.

An outbreak of infection due to severe acute respiratory corona virus-2 in a neonatal unit from a low and middle income setting

Introduction

The provision of kangaroo mother care (KMC) involving continuous skin-to-skin care (SSC) is an important intervention in neonatal care, which is recommended even when women are infected with severe acute respiratory syndrome coronavirus (SARS-CoV-2). We report on a nosocomial outbreak of SARS-CoV-2 infections in a KMC ward.

Methods

Contact tracing was conducted following the diagnosis of SARS-CoV-2 in a mother lodging in the KMC ward. All mother-newborn dyads in the KMC and healthcare workers (HCW) were tested for SARS-CoV-2 within 24-72 h of diagnosing the index case. Nasopharyngeal swab samples were obtained and tested from contacts, with a nucleic acid amplification test (NAAT) assay. Next-generation sequencing was done on positive samples. The secondary attack rate (SAR) was calculated assuming that the mother who presented with symptoms was the source of infection.

Results

Twelve (70.6%) of 17 mothers and 8 (42.1%) of 19 neonates who were in the KMC ward with the index case were found to be positive with SARS-CoV-2. Seven (87.5%) of the 8 neonates who tested positive had mothers who also tested positive. Seventy-five percent (9/12) of the mothers and 62.5% (5/8) of the neonates who tested positive were asymptomatic. Eight (27.6%) of 29 HCW were found to be positive and were all asymptomatic. One neonate died from Acinetobacter baumannii sepsis, and his post-mortem lung histopathology showed features compatible with SARS-CoV-2 pneumonia. The sequencing of 13 specimens, which included 1 mother-newborn dyad, indicated clustering to the same phylogenetic lineage with identical mutations. In assessing for factors contributing to this outbreak, it was found that spaces between beds were less than 1 m and mothers had their meals around the same table at the same time.

Conclusion

We report on a nosocomial outbreak of SARS-CoV-2 in a KMC ward, affecting a high number of mothers and neonates, and to a lesser extent HCWs. Although it is difficult to point to the index case as the source of this outbreak, as asymptomatic individuals can spread infection, the inadequate adherence to non-pharmaceutical interventions was assessed to have contributed to the spread of infection. This highlights the need for awareness and adherence to mitigation strategies to avoid SARS-CoV-2 outbreaks.

Derivation and validation of a novel risk assessment tool to identify children aged 2–59 months at risk of hospitalised pneumonia-related mortality in 20 countries

Introduction

Existing risk assessment tools to identify children at risk of hospitalised pneumonia-related mortality have shown suboptimal discriminatory value during external validation. Our objective was to derive and validate a novel risk assessment tool to identify children aged 2–59 months at risk of hospitalised pneumonia-related mortality across various settings.

Methods

We used primary, baseline, patient-level data from 11 studies, including children evaluated for pneumonia in 20 low-income and middle-income countries. Patients with complete data were included in a logistic regression model to assess the association of candidate variables with the outcome hospitalised pneumonia-related mortality. Adjusted log coefficients were calculated for each candidate variable and assigned weighted points to derive the Pneumonia Research Partnership to Assess WHO Recommendations (PREPARE) risk assessment tool. We used bootstrapped selection with 200 repetitions to internally validate the PREPARE risk assessment tool.

Results

A total of 27 388 children were included in the analysis (mean age 14.0 months, pneumonia-related case fatality ratio 3.1%). The PREPARE risk assessment tool included patient age, sex, weight-for-age z-score, body temperature, respiratory rate, unconsciousness or decreased level of consciousness, convulsions, cyanosis and hypoxaemia at baseline. The PREPARE risk assessment tool had good discriminatory value when internally validated (area under the curve 0.83, 95% CI 0.81 to 0.84).

Conclusions

The PREPARE risk assessment tool had good discriminatory ability for identifying children at risk of hospitalised pneumonia-related mortality in a large, geographically diverse dataset. After external validation, this tool may be implemented in various settings to identify children at risk of hospitalised pneumonia-related mortality.

High-throughput nanofluidic real-time PCR to discriminate Pneumococcal Conjugate Vaccine (PCV)-associated serogroups 6, 18, and 22 to serotypes using modified oligonucleotides

Current real-time high-throughput Polymerase Chain Reaction (qPCR) methods do not distinguish serotypes 6A from 6B, 18C from 18A/B and 22F from 22A. We established a nanofluidic real-time PCR (Fluidigm) for serotyping that included Dual-Priming-Oligonucleotides (DPO), a Locked-Nucleic-Acid (LNA) probe and TaqMan assay-sets for high-throughput serotyping. The designed assay-sets target capsular gene wciP in serogroup 6, wciX and wxcM in serogroup 18, and wcwA in serogroup 22. An algorithm combining results from published assay-sets (6A/B/C/D; 6C/D; 18A/B/C; 22A/F) and designed assay-sets for 6A/C; 18B/C/F; 18C/F, 18F and 22F was validated through blind analysis of 1973 archived clinical samples collected from South African children ≤ 5-years-old (2009–2011), previously serotyped with the culture-based Quellung method. All assay-sets were efficient (92–101%), had low variation between replicates (R² > 0.98), and were able to detect targets at a limit of detection (LOD) of < 100 Colony-Forming-Units (CFU)/mL of sample. There was high concordance (Kappa = 0.73–0.92); sensitivity (85–100%) and specificity (96–100%) for Fluidigm compared with Quellung for serotyping 6A; 6B; 6C; 18C and 22F. Fluidigm distinguishes vaccine-serotypes 6A, 6B, 18C, next-generation PCV-serotype 22F and non-vaccine-serotypes 6C, 6D, 18A, 18B, 18F and 22A. Discriminating single serotypes is important for assessing serotype replacement and the impact of PCVs on vaccine- and non-vaccine serotypes.

External validation of the RISC, RISC-Malawi, and PERCH clinical prediction rules to identify risk of death in children hospitalized with pneumonia

BACKGROUND

Existing scores to identify children at risk of hospitalized pneumonia-related mortality lack broad external validation. Our objective was to externally validate three such risk scores.

METHODS

We applied the Respiratory Index of Severity in Children (RISC) for HIV-negative children, the RISC-Malawi, and the Pneumonia Etiology Research for Child Health (PERCH) scores to hospitalized children in the Pneumonia REsearch Partnerships to Assess WHO REcommendations (PREPARE) data set. The PREPARE data set includes pooled data from 41 studies on pediatric pneumonia from across the world. We calculated test characteristics and the area under the curve (AUC) for each of these clinical prediction rules.

RESULTS

The RISC score for HIV-negative children was applied to 3574 children 0-24 months and demonstrated poor discriminatory ability (AUC = 0.66, 95% confidence interval (CI) = 0.58-0.73) in the identification of children at risk of hospitalized pneumonia-related mortality. The RISC-Malawi score had fair discriminatory value (AUC = 0.75, 95% CI = 0.74-0.77) among 17 864 children 2-59 months. The PERCH score was applied to 732 children 1-59 months and also demonstrated poor discriminatory value (AUC = 0.55, 95% CI = 0.37-0.73).

CONCLUSIONS

In a large external application of the RISC, RISC-Malawi, and PERCH scores, a substantial number of children were misclassified for their risk of hospitalized pneumonia-related mortality. Although pneumonia risk scores have performed well among the cohorts in which they were derived, their performance diminished when externally applied. A generalizable risk assessment tool with higher sensitivity and specificity to identify children at risk of hospitalized pneumonia-related mortality may be needed. Such a generalizable risk assessment tool would need context-specific validation prior to implementation in that setting.

Asymptomatic COVID-19 in South Africa - implications for the control of transmission

Asymptomatic COVID-19 may contribute significantly to the pandemic trajectory based on global biological, epidemiological and modelling evidence. A retrospective analysis was done to determine the proportion of asymptomatic COVID-19 in the workplace during the lockdown period from 27 March to 31 May 2020. We found that nearly 45% of cases were asymptomatic at the time of the first test. This high proportion of asymptomatic COVID-19 cases has implications for interventions, such as enforcing quarantine of all close contacts of COVID-19 cases regardless of symptoms.

COVID-19 vaccines - less obfuscation, more transparency and action

Letter by Venter et al. on editorial  by Schoub (Dial down the rhetoric over COVID-19 vaccines. S Afr Med J 2021;111(6):522-523. https://doi.org/10.7196/SAMJ.2021.v111i6.15740).

Diagnosis and management of community-acquired pneumonia in children: South African Thoracic Society guidelines

BACKGROUND

Pneumonia remains a major cause of morbidity and mortality amongst South African children. More comprehensive immunisation regimens, strengthening of HIV programmes, improvement in socioeconomic conditions and new preventive strategies have impacted on the epidemiology of pneumonia. Furthermore, sensitive diagnostic tests and better sampling methods in young children improve aetiological diagnosis.

OBJECTIVES

To produce revised guidelines for pneumonia in South African children under 5 years of age.

METHODS

The Paediatric Assembly of the South African Thoracic Society and the National Institute for Communicable Diseases established seven expert subgroups to revise existing South African guidelines focusing on: (i) epidemiology; (ii) aetiology; (iii) diagnosis; (iv) antibiotic management and supportive therapy; (v) management in intensive care; (vi) prevention; and (vii) considerations in HIV-infected or HIVexposed, uninfected (HEU) children. Each subgroup reviewed the published evidence in their area; in the absence of evidence, expert opinion was accepted. Evidence was graded using the British Thoracic Society (BTS) grading system. Sections were synthesized into an overall guideline which underwent peer review and revision.

RECOMMENDATIONS

Recommendations include a diagnostic approach, investigations, management and preventive strategies. Specific recommendations for HIV infected and HEU children are provided.

VALIDATION

The guideline is based on available published evidence supplemented by the consensus opinion of SA paediatric experts. Recommendations are consistent with those in published international guidelines.

Streptococcus pneumoniae colonization in pneumococcal vaccine-naïve human immunodeficiency virus-exposed infected and -uninfected South African children

Pneumococcal nasopharyngeal colonization is a pre-requisite for pneumococcal disease; the risk for pneumococcal disease is high in children born to women living with human immunodeficiency virus (HIV). We investigated pneumococcal colonization, serotype distribution and antibiotic susceptibility of Streptococcus pneumoniae isolates carried by perinatal HIV-infected and HIV-exposed-uninfected (HEU) children.Serial nasopharyngeal swabs were collected from 331 HIV-infected and 491 HEU children, at up to 6 scheduled timepoints, between median ages of 25 to 181 weeks. Pneumococcus was identified by culture; serotyping and antibiotic susceptibility testing were done by conventional methods. No pneumococcal vaccine was given.HIV-infected children were less likely to be colonized with 7-valent pneumococcal conjugate vaccine 7 serotypes than HEU at a median of 25 weeks of age (23% vs 36%; P < .001); however, no differences in colonization between the 2 groups were observed at subsequent study-visits. Over the 36-months study-period pneumococcal colonization increased in both HIV-infected (from 45% to 77%) and HEU (from 57% to 61%) children. Over the study-period, pneumococcal isolates non-susceptible to cotrimoxazole decreased from 92% to 57% and had a similar trend to penicillin (from 65% to 42%) in HIV-infected children. Similarly, pneumococcal nonsusceptible to cotrimoxazole decreased from 93% to 57% and to penicillin from 69% to 37% in HEU children.Vaccine serotype colonization was common in this population and similar rates were observed in HIV-infected and HEU children. The prevalence of pneumococcal isolates non-susceptible to cotrimoxazole and penicillin decreased with age.

Measles seroprevalence in pregnant women in Soweto, South Africa: a nested cohort study

OBJECTIVES

Measles infection causes particularly severe disease in young children who, prior to vaccination, are dependent on maternal antibodies for protection against infection. Measles vaccination was introduced into the South African public immunization programme in 1983 and became widely available in 1992. The aim of this study was to determine measles-specific immunoglobulin G (IgG) levels in pregnant women living with and without HIV born before and after measles vaccine introduction in South Africa.

METHODS

Measles IgG antibody level from blood obtained at the time of delivery was compared between women who were born before 1983 (n = 349) and since 1992 (n = 349). Serum samples were tested for measles IgG antibody using an enzyme-linked immunosorbent assay. Geometric mean titres (GMTs) and the proportion with seronegative (<200 mIU/mL) or seropositive titres (≥275 mIU/mL) were compared.

RESULTS

Women born since 1992 had lower GMTs [379.7 mIU/mL (95% CI 352.7-448.6)] and fewer were seropositive (55.9%, 195/349) than women born before 1983 [905.8 mIU/mL (95% CI 784.7-1045.5); 76.8%, 268/349], for both comparisons p < 0.001.

CONCLUSIONS

We found an association between measles vaccine implementation into the public immunization program in South Africa and peri-partum maternal measles immunity, where women born before vaccine introduction had higher measles IgG antibody titres and were more likely to be seropositive. These findings suggest a need to reconsider the infant measles immunization schedule in settings where women have derived immunity mainly from measles vaccine rather than wild-type virus exposure.

Vaccinology in sub-Saharan Africa

We undertook a landscape analysis of vaccinology research and training in sub-Saharan Africa in order to identify key gaps and opportunities for capacity development in the field. We conducted interviews with regional and global immunisation experts, reviewed university and research centre websites, searched the scientific literature and analysed donor databases as part of our mapping exercise. We found that (1) few vaccinology training programmes are available in the region; (2) vaccinology research sites are numerous but unevenly distributed across countries and subregions and of widely varying capacity; (3) donor funding favours HIV, tuberculosis and malaria vaccine development over other high-burden diseases; (4) lack of vaccine design, manufacturing and regulatory capacity slows the progress of new vaccines through the research and development pipeline and (5) vaccine implementation research garners limited support. Regional efforts to strengthen African vaccinology expertise should develop advanced vaccinology training programmes, support clinical trial and implementation research sites in geographic areas with limited capacity and conduct multidisciplinary research to help design, license and roll out new vaccines.

Use of antiretrovirals in HIV-infected children in a tuberculosis prevention trial: IMPAACT P1041

SETTING

International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) P1041, a tuberculosis (TB) prevention trial conducted among children enrolled from 2004 to 2008 during South Africa's roll-out of combination antiretroviral therapy (ART).

OBJECTIVE

To estimate TB incidence and mortality and the effect of ART.

DESIGN

Children were pre-screened to exclude TB disease and exposure, actively screened 3-monthly for TB exposure and symptoms, and provided post-exposure isoniazid prophylaxis therapy (IPT). TB diagnoses were definite, probable, or possible, and mortality all-cause. Testing was at the 5% significance level.

RESULTS

In 539 children (aged 3-4 months) followed up for a median of 74 weeks (interquartile range [IQR] 48-116), incidence/100 person-years (py) was 10.67 (95%CI 8.47-13.26) for any TB and 2.89 (95%CI 1.85-4.31) for definite/probable TB. Any TB incidence was respectively 9.39, 13.59, and 9.83/100 py before, <180 days after, and 180 days after ART initiation. Adjusted analysis showed a non-significant increase in any TB (HR 1.32, 95%CI 0.71-2.52, P = 0.38) and a significant reduction in mortality (HR 0.39, 95%CI 0.17-0.82, P = 0.017) following ART initiation.

CONCLUSIONS

ART reduced mortality but not TB incidence in human immunodeficiency virus (HIV) infected children in IMPAACT P1041, possibly attributable to active screening for TB exposure and symptoms with post-exposure IPT. Research into this as a strategy for TB prevention in high HIV-TB burden settings may be warranted.

Incidence of tuberculosis meningitis in a high HIV prevalence setting: time-series analysis from 2006 to 2011

SETTING

This study was undertaken at a tertiary hospital in Soweto, a peri-urban low-middle income setting. Mycobacterium tuberculosis meningitis (TBM) is a severe manifestation of extra-pulmonary tuberculosis.

OBJECTIVE

To describe the incidence, mortality and clinical features of TBM in human immunodeficiency virus (HIV) infected and non-infected children in South Africa from 2006 to 2011.

DESIGN

A retrospective, cross-sectional descriptive study.

METHODS

Electronic databases and individual patient records of all children with a discharge diagnosis of TBM were reviewed to yield incidence rate ratios (IRR) in HIV-infected and non-infected children. Clinical, laboratory and radiological characteristics were compared between HIV-infected and non-infected children with TBM.

RESULTS

Overall TBM incidence per 100 000 population in 2006 was 6.9 (95%CI 4.4-10.3) and 9.8 (95%CI 6.9-13.6) in 2009, but had subsequently declined to 3.1 (95%CI 1.6-5.5) by 2011. There was a significant reduction in the IRR of TBM among HIV-infected children (IRR 0.916, P = 0.036). The overall case fatality ratio was 6.7%. Clinical features, cerebrospinal fluid and computed tomography brain findings were similar in HIV-infected and non-infected children.

CONCLUSION

TBM incidence decreased over the study period from 2006 to 2011, and was temporally associated with an increase in the uptake of antiretroviral treatment in HIV-infected individuals.

Source case identification in HIV-exposed infants and tuberculosis diagnosis in an isoniazid prevention study

BACKGROUND

Identifying source cases of children exposed to tuberculosis (TB) is challenging. We examined the time-point of obtaining contact information of TB source cases in human immunodeficiency virus (HIV) infected and HIV-exposed uninfected (HEU) children in a randomised, placebo-controlled trial of pre-exposure to isoniazid prophylaxis.

METHODS

A total of 543 HIV-infected and 808 HEU infants without TB exposure aged 3-4 months were enrolled between 2004 and 2008. At 3-monthly follow-up, infants were evaluated for TB and care givers were asked about new TB exposure.

RESULTS

In total, 128 cases of TB disease and 40 deaths were recorded among 19% (105/543) of the HIV-infected and 8% (63/808) of the HEU children; 229 TB contact occasions were reported in 205/1351 (15%) children, of which 83% (189/229) were in the household. Of the 189 household contacts, 108 (53%) underwent microbiological evaluations; 81% (87/108) were positive. HIV-infected and HEU infants had similar frequencies of TB contact: in 48% of infants with definite TB, 58% with probable TB and 43% with possible TB. Of 128 children diagnosed with TB, a TB contact was identified for 59. Of these, 29/59 (49%) were identified at or after the child's TB diagnosis.

CONCLUSION

TB source cases are often identified at or after a child's TB diagnosis. More effort is required for earlier detection.

Temporal association of rotavirus vaccination and genotype circulation in South Africa: Observations from 2002 to 2014

BACKGROUND

Rotavirus vaccination has reduced diarrhoeal morbidity and mortality globally. The monovalent rotavirus vaccine was introduced into the public immunization program in South Africa (SA) in 2009 and led to approximately 50% reduction in rotavirus hospitalization in young children. The aim of this study was to investigate the rotavirus genotype distribution in SA before and after vaccine introduction.

MATERIALS AND METHODS

In addition to pre-vaccine era surveillance conducted from 2002 to 2008 at Dr George Mukhari Hospital (DGM), rotavirus surveillance among children <5 years hospitalized for acute diarrhoea was established at seven sentinel sites in SA from April 2009 to December 2014. Stool specimens were screened by enzyme immunoassay and rotavirus positive specimens genotyped using standardised methods.

RESULTS

At DGM, there was a significant decrease in G1 strains from pre-vaccine introduction (34%; 479/1418; 2002-2009) compared to post-vaccine introduction (22%; 37/170; 2010-2014; p for trend <.001). Similarly, there was a significant increase in non-G1P[8] strains at this site (p for trend <.001). In expanded sentinel surveillance, when adjusted for age and site, the odds of rotavirus detection in hospitalized children with diarrhoea declined significantly from 2009 (46%; 423/917) to 2014 (22%; 205/939; p<.001). The odds of G1 detection declined significantly from 2009 (53%; 224/421) to 2010-2011 (26%; 183/703; aOR=0.5; p<.001) and 2012-2014 (9%; 80/905; aOR=0.1; p<.001). Non-G1P[8] strains showed a significant increase from 2009 (33%; 139/421) to 2012-2014 (52%; 473/905; aOR=2.5; p<.001).

CONCLUSIONS

Rotavirus vaccination of children was associated with temporal changes in circulating genotypes. Despite these temporal changes in circulating genotypes, the overall reduction in rotavirus disease in South Africa remains significant.

Acute viral bronchiolitis in South Africa: Diagnostic flow

Bronchiolitis may be diagnosed on the basis of clinical signs and symptoms. In a young child, the diagnosis can be made on the clinical pattern of wheezing and hyperinflation. Clinical symptoms and signs typically start with an upper respiratory prodrome, including rhinorrhoea, low-grade fever, cough and poor feeding, followed 1 - 2 days later by tachypnoea, hyperinflation and wheeze as a consequence of airway inflammation and air trapping.The illness is generally self limiting, but may become more severe and include signs such as grunting, nasal flaring, subcostal chest wall retractions and hypoxaemia. The most reliable clinical feature of bronchiolitis is hyperinflation of the chest, evident by loss of cardiacdullness on percussion, an upper border of the liver pushed down to below the 6th intercostal space, and the presence of a Hoover sign(subcostal recession, which occurs when a flattened diaphragm pulls laterally against the lower chest wall).Measurement of peripheral arterial oxygen saturation is useful to indicate the need for supplemental oxygen. A saturation of <92% at sea level and 90% inland indicates that the child has to be admitted to hospital for supplemental oxygen. Chest radiographs are generally unhelpful and not required in children with a clear clinical diagnosis of bronchiolitis.Blood tests are not needed routinely. Complete blood count tests have not been shown to be useful in diagnosing bronchiolitis or guiding its therapy. Routine measurement of C-reactive protein does not aid in management and nasopharyngeal aspirates are not usually done.Viral testing adds little to routine management. Risk factors in patients with severe bronchiolitis that require hospitalisation and may even cause death, include prematurity, congenital heart disease and congenital lung malformations.

Acute viral bronchiolitis in South Africa: Strategies for management and prevention

Management of acute viral bronchiolitis is largely supportive. There is currently no proven effective therapy other than oxygen for hypoxic children. The evidence indicates that there is no routine benefit from inhaled, rapid short-acting bronchodilators, adrenaline or ipratropium bromide for children with acute viral bronchiolitis. Likewise, there is no demonstrated benefit from routine use of inhaled or oral corticosteroids, inhaled hypertonic saline nebulisation, montelukast or antibiotics. The last should be reserved for children with severe disease, when bacterial co-infection is suspected. Prevention of respiratory syncytial virus (RSV) disease remains a challenge. A specific RSV monoclonal antibody, palivizumab, administered as an intramuscular injection, is available for children at risk of severe bronchiolitis, including premature infants, young children with chronic lung disease, immunodeficiency, or haemodynamically significant congenital heart disease. Prophylaxis should be commenced at the start of the RSV season and given monthly during the season. The development of an RSV vaccine may offer a more effective alternative to prevent disease, for which the results of clinical trials are awaited. Education of parents or caregivers and healthcare workers about diagnostic and management strategies should include the following: bronchiolitis is caused by a virus; it is seasonal; it may start as an upper respiratory tract infection with low-grade fever; symptoms are cough and wheeze, often with fast breathing; antibiotics are generally not needed; and the condition is usually self limiting, although symptoms may occur for up to four weeks in some children.

Advocating for efforts to protect African children, families, and communities from the threat of infectious diseases: report of the First International African Vaccinology Conference

One means of improving healthcare workers’ knowledge of and attitudes to vaccines is through running vaccine conferences which are accessible, affordable, and relevant to their everyday work. Various vaccinology conferences are held each year worldwide. These meetings focus heavily on basic science with much discussion about new developments in vaccines, and relatively little coverage of policy, advocacy, and communication issues. A negligible proportion of delegates at these conferences come from Africa, home to almost 40% of the global burden of vaccine-preventable diseases. To the best of our knowledge, no major vaccinology conference has ever been held on the African continent apart from World Health Organization (WHO) meetings. The content of the first International African Vaccinology Conference was planned to be different; to focus on the science, with a major part of discussions being on clinical, programmatic, policy, and advocacy issues. The conference was held in Cape Town, South Africa, from 8 to 11 November 2012. The theme of the conference was “Advocating for efforts to protect African children, families, and communities from the threat of infectious diseases”. There were more than 550 registered participants from 55 countries (including 37 African countries). There were nine pre-conference workshops, ten plenary sessions, and 150 oral and poster presentations. The conference discussed the challenges to universal immunisation in Africa as well as the promotion of dialogue and communication on immunisation among all stakeholders. There was general acknowledgment that giant strides have been made in Africa since the global launch of the Expanded Programme on Immunisation in 1974. For example, there has been significant progress in introducing new and under-utilised vaccines; including hepatitis B, Haemophilus influenza type b, pneumococcal conjugate, rotavirus, meningococcal A conjugate, and human papillomavirus vaccines. In May 2012, African countries endorsed the Global Vaccine Action Plan at the World Health Assembly. However, more than six million children remain incompletely vaccinated in Africa leading to more than one million vaccine-preventable deaths annually. In addition, there are persistent problems with leadership and planning, vaccine stock management, supply chain capacity and quality, provider-parent communication, and financial sustainability. The conference delegates agreed to move from talking to taking concrete actions around children's health, and to ensure that African governments commit to saving children's lives. They would advocate for lower costs of immunisation programmes in Africa, perhaps through bulk buying and improved administration of vaccine rollout through the New Partnership for Africa's Development.

Maternal group B Streptococcus-related stillbirth: a systematic review

BACKGROUND

Limited epidemiological data on the association between maternal rectovaginal group B Streptococcus (GBS) colonisation and stillbirth makes assessment of antenatal interventions for GBS stillbirth difficult.

OBJECTIVES

To systematically review the existing literature and evaluate the incidence of GBS-related stillbirth by region up to March 2015.

SEARCH STRATEGY

A systematic review of the published literature was completed using PubMed/MEDLINE, EMBASE, LILACS, and Cochrane Library, with Medical Subject Headings (MeSH) and search terms based upon the Centers for Disease Control and Prevention's (CDC) Active Bacterial Core Surveillance (ABCs) GBS-related stillbirth definition and chorioamnionitis.

SELECTION CRITERIA

Studies reporting original data on GBS-related stillbirth occurring ≥20 weeks of gestation, with GBS confirmed by autopsy or by culture from the placenta, amniotic fluid, or other normally sterile site samples from the stillborn.

DATA COLLECTION AND ANALYSIS

Descriptive analyses were performed with the absolute GBS-related stillbirth rates and proportion of stillbirths attributed to GBS calculated per study where possible. Differences in stillbirth definitions did not allow for pooled estimates to be calculated.

MAIN RESULTS

Seventeen studies reported GBS-related stillbirth rates varying from 0.04 to 0.9 per 1000 births, with the proportion of stillbirths associated with GBS ranging from 0 to 12.1%. Most studies reported data from before the year 2000 and from high-income countries.

CONCLUSIONS

The sparsely available epidemiological evidence was not reported consistently, emphasising the importance of standardised stillbirth definitions and diagnostic methods to optimally assess the effectiveness of any future antenatal interventions. Timing of stillbirth, GBS serotype, and global diversity were gaps in the current evidence.

TWEETABLE ABSTRACT

Systematic review finds Group B Streptococcus causes up to 12.1% of stillbirths, but more research is needed.

Natural acquired humoral immunity against serotype-specific group B Streptococcus rectovaginal colonization acquisition in pregnant women

Group B Streptococcus (GBS) rectovaginal colonization in pregnant women is associated with invasive GBS disease in newborns, preterm delivery and stillbirths. We studied the association of GBS serotype-specific capsular polysaccharide (CPS) antibody on new acquisition and clearance of rectovaginal GBS colonization in pregnant women from 20 weeks until 37 to 40 weeks' gestation. Serum serotype-specific CPS IgG antibody concentration was measured by multiplex enzyme-linked immunosorbent assay and opsonophagocytic activity (OPA) titres. Rectovaginal swabs were evaluated for GBS colonization, using standard culture methods and serotyping by latex agglutination, at five to six weekly intervals. Higher serotype III CPS antibody concentration was associated with lower risk of rectovaginal acquisition of serotype III during pregnancy (p 0.009). Furthermore, serotype-specific OPA titres to Ia and III were higher in women who remained free of GBS colonization throughout the study compared to those who acquired the homotypic serotype (p <0.001 for both serotypes). Serum CPS IgG values of ≥1μg/mL for serotype V and ≥3μg/mL for serotypes Ia and III were significantly associated with protection against rectovaginal acquisition of the homotypic serotype. A GBS vaccine that induces sufficient capsular antibody in pregnant women, including high OPA titres, could protect against rectovaginal colonization during the latter half of pregnancy.

Temporal association of infant immunisation with pneumococcal conjugate vaccine on the ecology of Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus nasopharyngeal colonisation in a rural South African community

BACKGROUND

Immunisation of children with pneumococcal conjugate vaccines (PCV) may affect the bacterial-ecology of the nasopharynx, including colonisation by Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. The aim of this study was to evaluate the effect of infant PCV-immunisation on the nasopharyngeal ecology of these potentially pathogenic bacteria in a rural African setting.

METHODS

Two cross sectional surveys were undertaken from May to October in 2009 (Period-1) which coincided with the introduction of 7-valent PCV (PCV7) and in May-October 2011 (Period-2). Consenting household members, where there was a child <2 years of age in residence, had nasopharyngeal swabs undertaken for culture.

RESULTS

From Period-1 to Period-2 in children 0-2 years and 3-12 years, prevalence of overall S. pneumoniae colonisation decreased from 74.9% to 67.0% (p<0.001) and H. influenzae declined among children 3-12 years (55.1-45.3%, p<0.001) but not among those <2 years. The prevalence of S. aureus remained unchanged in all children. Competitive associations were found between S. pneumoniae and S. aureus and between H. influenzae and S. aureus among children. In individuals >12 years, the prevalence of colonisation decreased from 11.2% to 6.8%, 16.7% to 8.8% and 31.2% to 23.7% for S. pneumoniae, H. influenzae and S. aureus, respectively; p<0.001 for all comparions. Synergistic relationships for S. aureus with H. influenzae and S. pneumoniae were observed in both periods among this group.

Pneumonia in low and middle income countries: progress and challenges

Pneumonia remains the leading cause of childhood mortality and the most common reason for adult hospitalisation in low and middle income countries, despite advances in preventative and management strategies. In the last decade, pneumonia mortality in children has fallen to approximately 1.3 million cases in 2011, with most deaths occurring in low income countries. Important recent advances include more widespread implementation of protein-polysaccharide conjugate vaccines against Haemophilus influenzae type B and Streptococcus pneumoniae, implementation of case-management algorithms and better prevention and treatment of HIV. Determining the aetiology of pneumonia is challenging in the absence of reliable diagnostic tests. High uptake of new bacterial conjugate vaccines may impact on pneumonia burden, aetiology and empiric therapy but implementation in immunisation programmes in many low and middle income countries remains an obstacle. Widespread implementation of currently effective preventative and management strategies for pneumonia remains challenging in many low and middle income countries.

Respiratory viral and pneumococcal coinfection of the respiratory tract: implications of pneumococcal vaccination

The interactions between Streptococcus pneumoniae and other respiratory pathogens have been studied in vitro, in animal models and in humans - including epidemiologic and vaccine probe studies. Interactions of pneumococcus with respiratory viruses are common, and many mechanisms have been suggested to explain this phenomenon. The aim of this review is to explore pneumococcal interactions with respiratory viruses and consider the potential role that the pneumococcal polysaccharide-protein conjugate vaccine may play in modifying pneumococcal-respiratory viral interactions.

Community-onset Staphylococcus aureus bacteraemia in hospitalised African children: high incidence in HIV-infected children and high prevalence of multidrug resistance

BACKGROUND

Invasive bacterial disease causes significant morbidity and mortality in children in developing countries. The burden of invasive disease caused by Staphylococcus aureus and S. aureus antimicrobial resistance patterns in African children in settings with a high prevalence of HIV infection remain ill-defined.

AIMS AND OBJECTIVES

To describe the burden of community-onset bacteraemic S. aureus infections in children in an area with a high prevalence of paediatric HIV infection, and to describe the antimicrobial resistance patterns.

METHODS

A retrospective record review of children hospitalised at Chris Hani Baragwanath Hospital, Soweto, with S. aureus bacteraemia between January 2005 and December 2006 was conducted. Community-onset S. aureus bloodstream infections were defined as S. aureus cultured from blood obtained within 48 hours of admission.

RESULTS

Community-onset S. aureus bacteraemia was identified in 161 children, representing an incidence of 26/100,000, with 63 (39%) isolates identified as methicillin-resistant (10/100,000). The incidence of community-onset S. aureus bacteraemia, both methicillin-susceptible and methicillin-resistant, was inversely related to age and greater in HIV-infected than uninfected children. High rates of antibiotic resistance were observed in MRSA isolates and only resistance to amikacin, fusidic acid and ciprofloxacin was <40%. MRSA isolates were frequently multidrug-resistant. Among HIV-infected children, resistance to trimethoprim-sulfamethoxazole was 100% and to rifampicin was 78%.

CONCLUSIONS

This study highlights the burden of S. aureus bacteraemia in a setting with a high prevalence of paediatric HIV infection. The high incidence of S. aureus bacteraemia coupled with a high prevalence of methicillin resistance, particularly in HIV-infected children, needs to be considered in the empirical management of paediatric sepsis in settings such as ours.

Early antiretroviral treatment reduces risk of bacille Calmette-Guérin immune reconstitution adenitis

SETTING

Two centres in Soweto and Cape Town, South Africa.

OBJECTIVE

To assess the effects of timing of initiation of antiretroviral treatment (ART) and other factors on the risk of bacille Calmette-Guérin (BCG) related regional adenitis due to immune reconstitution inflammatory syndrome (BCG-IRIS) in human immunodeficiency virus (HIV) infected infants.

DESIGN

HIV-infected infants aged 6-12 weeks with CD4 count ≥25% enrolled in the Children with HIV Early Antiretroviral Therapy (CHER) Trial received early (before 12 weeks) or deferred (after immunological or clinical progression) ART; infants with CD4 count <25% all received early ART. All received BCG vaccination after birth. Reactogenicity to BCG was assessed prospectively during routine study follow-up.

RESULTS

Of 369 infants, 32 (8.7%) developed BCG-IRIS within 6 months of starting ART, 28 (88%) within 2 months after ART initiation. Of the 32 cases, 30 (93.8%) had HIV-1 RNA > 750 000 copies/ml at initiation. Incidence of BCG-IRIS was 10.9 and 54.3 per 100 person-years (py) among infants with CD4 count ≥25% at enrolment receiving early (at median age 7.4 weeks) vs. deferred (23.2 weeks) ART, respectively (HR 0.24, 95%CI 0.11-0.53, P < 0.001). Infants with CD4 count <25% receiving early ART had intermediate incidence (41.7/100 py). Low CD4 counts and high HIV-1 RNA at initiation were the strongest independent risk factors for BCG-IRIS.

CONCLUSIONS

Early ART initiation before immunological and/or clinical progression substantially reduces the risk of BCG-IRIS regional adenitis.

Use of a rapid test of pneumococcal colonization density to diagnose pneumococcal pneumonia

BACKGROUND

There is major need for a more sensitive assay for the diagnosis of pneumococcal community-acquired pneumonia (CAP). We hypothesized that pneumococcal nasopharyngeal (NP) proliferation may lead to microaspiration followed by pneumonia. We therefore tested a quantitative lytA real-time polymerase chain reaction (rtPCR) on NP swab samples from patients with pneumonia and controls.

METHODS

In the absence of a sensitive reference standard, a composite diagnostic standard for pneumococcal pneumonia was considered positive in South African human immunodeficiency virus (HIV)-infected adults hospitalized with radiographically confirmed CAP, if blood culture, induced good-quality sputum culture, Gram stain, or urinary Binax demonstrated pneumococci. Results of quantitative lytA rtPCR in NP swab samples were compared with quantitative colony counts in patients with CAP and 300 HIV-infected asymptomatic controls.

RESULTS

Pneumococci were the leading pathogen identified in 76 of 280 patients with CAP (27.1%) using the composite diagnostic standard. NP colonization density measured by lytA rtPCR correlated with quantitative cultures (r = 0.67; P < .001). The mean lytA rtPCR copy number in patients with pneumococcal pneumonia was 6.0 log(10) copies/mL, compared with patients with CAP outside the composite standard (2.7 log(10) copies/mL; P < .001) and asymptomatic controls (0.8 log(10) copies/mL; P < .001). A lytA rtPCR density ≥8000 copies/mL had a sensitivity of 82.2% and a specificity of 92.0% for distinguishing pneumococcal CAP from asymptomatic colonization. The proportion of CAP cases attributable to pneumococcus increased from 27.1% to 52.5% using that cutoff.

CONCLUSIONS

A rapid molecular assay of NP pneumococcal density performed on an easily available specimen may significantly increase pneumococcal pneumonia diagnoses in adults.

One-year post-primary antibody persistence and booster immune response to a DTaP-IPV//PRP~T vaccine (Pentaxim) given at 18 - 19 months of age in South African children primed at 6, 10 and 14 weeks of age with the same vaccine

OBJECTIVE

To assess the immunogenicity and safety of a pentavalent diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Hib polysaccharide-conjugate vaccine booster.

DESIGN, SETTING AND PARTICIPANTS

A DTaP-IPV//PRP~T vaccine (Pentaxim, a Sanofi Pasteur AcXim family vaccine) was given to 182 healthy children in South Africa at 18 - 19 months of age following priming with the same vaccine plus a monovalent hepatitis B vaccine at 6, 10 and 14 weeks of age. Outcome measures. Seroprotection (SP) and seroconversion (SC) rates, geometric mean titres (GMTs) and concentrations (GMCs) were assessed before, and 1 month after, the booster dose. Safety was assessed using parental reports.

RESULTS

One month after primary vaccination, at least 94.3% of participants were seroprotected against tetanus (≥ 0.01 IU/ml), diphtheria (≥ 0.01 IU/ml), poliovirus (≥ 8 1/dil) and Haemophilus influenzae type b (Hib) infection (≥ 0.15 µg/ml). Before the booster dose, the SP rates ranged from 65.7% to 100%. One month after the booster dose, SP rates were 97.7% for Hib (anti-PRP titre 1.0 μg/ml), 100.0% for diphtheria (≥ 0.1 IU/ml) and 100% for tetanus (≥ 0.1 IU/ml) and poliovirus types 1, 2, 3 (≥ 8 1/dil). At least 95.7% of participants had 4 fold post-booster increases in anti-pertussis antibody titres. GMTs increased from 11.21 to 465.51 EU/ml and from 12.89 to 520.35 EU/ml for anti-PT and anti-FHA respectively. Anti-PRP GMT increased from 0.35 to 47.01 μg/ml. The DTaP-IPV//PRP~T vaccine booster was well tolerated, with fever ≥ 39.0°C in only 1.7% of participants.

CONCLUSIONS

Antibody persistence following priming was satisfactory. The pentavalent DTaP-IPV//PRP~T vaccine booster was highly immunogenic and well tolerated.

QuantiFERON-TB Gold In-Tube for the detection of Mycobacterium tuberculosis infection in children with household tuberculosis contact

SETTING

Improved strategies are needed for detecting Mycobacterium tuberculosis infection in children in TB-endemic settings.

OBJECTIVE

To determine the prevalence of M. tuberculosis infection by tuberculin skin testing (TST) and by the QuantiFERON-TB Gold In-Tube (QFT-GIT) test in children with an adult household contact with pulmonary TB in South Africa.

DESIGN

Cross-sectional study.

RESULTS

A total of 167 adult pulmonary TB cases (153/167, 92% human immunodeficiency virus [HIV] infected) and 270 pediatric contacts (median age 6 years, 14/270, 5% HIV-infected) were enrolled. All children completed QFT-GIT testing and 254 (94.1%) completed TST testing. Prevalence of M. tuberculosis infection was 28% (71/254, 95%CI 23-34) using TST (5 mm cut-off) and 29% (79/270, 95%CI 24-35) using QFT-GIT (P = 0.49). Agreement between TST and QFT-GIT was 81% (kappa 0.58). Nineteen (7%) QFT-GIT results were indeterminate. Children aged <2 years were more likely than older children to have indeterminate QFT-GIT results (aOR 5.7, 95%CI 1.5-22, P = 0.01) and discordant QFT-GIT and TST results (aOR 3.5, 95%CI 1.7-7.6, P = 0.001).

CONCLUSION

Prevalence of M. tuberculosis infection in pediatric contacts was high regardless of the diagnostic method used. TST should not be excluded for the detection of pediatric M. tuberculosis infection in this setting, but QFT-GIT may be a feasible alternative in children aged ≥ 2 years.

Antibiotic and systemic therapies for pneumonia in human immunodeficiency virus (HIV)-infected and HIV-exposed children

Introduction: Pneumonia is the leading cause of mortality in both human immunodeficiency virus (HIV)-infected and HIV-exposed children.  Administration of appropriate empirical antimicrobial and/or adjunctive systemic therapies may improve clinical outcomes. Methodology: To identify effective antimicrobial and/or adjunctive systemic therapy for pneumonia in HIV-infected and HIV-exposed, uninfected children, we searched for published and unpublished studies from 11 databases including MedLine, Global Health Database,  Biological Abstracts (BIOSIS), the Cochrane Central Register of Controlled Trials, the World Health Organization Library Information System, AIDSLine, and the System for Information on Grey Literature in Europe, along with additional four regional databases including African Index Medicus, Latin America and Caribbean, Eastern Mediterranean, and South-East Asian databases. Data from full articles of selected studies were independently extracted by two reviewers. Results: No a priori planned randomized controlled trials (RCT) were identified, only subgroup analyses of an RCT comparing oral amoxicillin versus parenteral penicillin for severe pneumonia in children. HIV-infected children had significantly higher treatment failure rates compared to their uninfected counterparts. An RCT study investigating adjunctive corticosteroid therapy for Pneumocystis jiroveci pneumonia (PCP) failed to identify a statistically significant reduction in mortality in the treatment group with a relative risk of 0.57 (95% CI 0.30-1.07). A before-after observational study showed substantial beneficial effect of corticosteroid treatment in reducing mortality among HIV-infected children with PCP. Conclusions: Insufficient evidence exists to identify effective antimicrobial treatment regimens for HIV-associated pneumonia in paediatric populations or confirm the beneficial effect of corticosteroid treatment for HIV-infected children with PCP. 

Tuberculosis culture testing at a tertiary care hospital: options for improved management and use for treatment decisions

SETTING

Chris Hani Baragwanath Hospital, a tertiary care hospital in Johannesburg, South Africa.

OBJECTIVES

To determine the proportion of patients with positive Mycobacterium tuberculosis cultures and whether those who were positive were on treatment.

DESIGN

Tuberculosis (TB) culture results were obtained from the laboratory for a 3-month period. Positive results were checked against registrations at the hospital TB Care Centre (TBCC). The treatment status of non-registered patients was obtained from various records at the hospital, district clinics and from home visits.

RESULTS

Overall, 3909 patients had 5404 samples sent for culture. Of these, 708 patients (18%) had at least one positive culture. The positive yield from 2749 adult sputum samples was 33% and ranged from 6% to 40% for different extra-pulmonary specimens. Among 1160 children, the yield varied from 0% to 12%, with 12% in sputum and gastric washing specimens. Of the 708 culture-positive patients, 429 (61%) patients were registered at the TBCC and were known to have started TB treatment. Of the 279 subjects not registered (39% overall), 100 (36%) died. Only 67 of the 179 survivors were confirmed on treatment, 40 were not on treatment and 72 could not be traced.

CONCLUSIONS

Large numbers of TB culture tests were performed, some inappropriately. Study findings highlight inadequacies in the management of culture-confirmed TB at this hospital.

Influenza guideline for South Africa--update 2008

OBJECTIVE

The South African Thoracic Society, in conjunction with interested stakeholders, published a Guideline for Influenza Management in Adults in 1999. This year the South African Thoracic Society (SATS) identified the need to revise that guideline for the following reasons: * To indicate the viral strains that are to be incorporated into the vaccine for the 2008 season * To add important new data regarding treatment of influenza * To add a section on influenza in children * To clarify issues in managing and preventing influenza in HIV-infected individuals.

INFLUENZA VIRUS

The influenza virus genus belongs to the family orthomyxoviridae. The haemagglutinin (HA) protein is the outermost protein, responsible for attachment to the host receptor, and is critical in determining the host's immune response to the virus. Changes in the antigenic epitopes of HA therefore allow the virus to escape the host's specific immune response. The genus is classified into three types, A, B and C, on the basis of the antigenic epitopes of the nucleoprotein (NP). Type A, which is widespread in nature in birds and mammals, is the most important type clinically and epidemiologically. It is further divided into subtypes on the basis of the antigenic epitopes of the HA and neuraminidase (NA) proteins. Each of the human subtypes H1N1, H2N2 and H3N2 are further subdivided into strains on the basis of more subtle antigenic properties of the HA protein.

INFLUENZA VACCINATION

Influenza vaccine is the mainstay of influenza prevention strategies. All persons who are at high risk of influenza and its complications because of underlying medical conditions or who are receiving regular medical care for conditions such as chronic pulmonary and cardiac disease, chronic renal diseases, neuromuscular diseases, diabetes mellitus and similar metabolic disorders, and individuals who are immunosuppressed (including HIV-infected persons with CD4 counts above 100 cells/microl and HIV-infected children with CD4 counts >15%), should be vaccinated. Vaccines should be given from at least 2 months prior to the onset of autumn (March in South Africa). The recommended vaccine formulation for 2008 is: * A/Solomon Islands/3/2006 (H1N1) (IVR-145) * A/Brisbane/10/2007 (H3N2) (IVR-147) * B/Florida/4/2006 or B/Brisbane/3/2007.

TREATMENT OF INFLUENZA

Influenza illness is characterised by the acute onset of systemic and respiratory signs occurring in autumn or winter. Recommendations for the Prevention and Control of Influenza have indicated that neither amantadine nor rimantadine should be used for the treatment or chemoprophylaxis of influenza A. NA inhibitors are an important adjunct to influenza vaccination, in both the prevention and treatment of influenza. Because of concerns about the possibility of the development of viral resistance with overuse of these agents, it is recommended that NA inhibitors in the treatment of influenza should be reserved for high-risk or sicker influenza patients.

Impact of conjugate Haemophilus influenzae type b (Hib) vaccine introduction in South Africa

OBJECTIVE

To analyse trends in reported invasive Haemophilus influenzae disease in South Africa within the first five years of introduction of conjugate Haemophilus influenzae type b (Hib) vaccine in the routine child immunization schedule.

METHODS

We used national laboratory-based surveillance data to identify cases of invasive H. influenzae disease between July 1999 and June 2004, and submitted isolates for serotyping and antimicrobial susceptibility testing.

FINDINGS

The absolute number of Hib cases (reported to the national surveillance system) among children below one year of age decreased by 65%, from 55 cases in 1999-2000 to 19 cases in 2003-04. Enhanced surveillance initiated in 2003, identified human immunodeficiency virus (HIV)-infection and incomplete vaccination as contributing factors for Hib transmission. The total number of laboratory-confirmed cases of H. influenzae remained unchanged because non-type b disease was being increasingly reported to the surveillance system concomitant with system enhancements. Children with non-typable disease were more likely to be HIV-positive (32 of 34, 94%) than children with Hib disease (10 of 14, 71%), P = 0.051. Recent Hib isolates were more likely to be multidrug resistant (2% in 1999-2000 versus 19% in 2003-04, P = 0.001).

CONCLUSION

Data from a newly established national laboratory-based surveillance system showed a decrease in Hib disease burden among South African children following conjugate vaccine introduction and identified cases of non-typable disease associated with HIV infection.

Diagnosis and management of community-acquired pneumonia in childhood--South African Thoracic Society Guidelines

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality in South African children. The incidence, severity and spectrum of childhood pneumonia have changed owing to the HIV epidemic. Increasing emergence of antimicrobial resistance necessitates a rational approach to the use of antibiotics in pneumonia management.

OBJECTIVE

To develop guidelines for the diagnosis, management and prevention of CAP in South African children.

METHODS

The Paediatric Assembly of the South African Thoracic Society established five expert subgroups to address: (i) epidemiology and aetiology; (ii) diagnosis; (iii) antibiotic treatment; (iv) supportive therapy; and (v) prevention of CAP. Each subgroup developed a position paper based on the available published evidence; in the absence of evidence, expert opinion was accepted. After peer review and revision, the position papers were synthesised into an overall guideline which was further reviewed and revised.

RECOMMENDATIONS

Recommendations based on epidemiological factors include a diagnostic approach, investigations, supportive therapy, appropriate antibiotic treatment and preventive strategies. Specific recommendations for HIV-infected children are provided.

VALIDATION

These guidelines are based on the available evidence supplemented by the consensus opinion of South African experts in paediatrics, paediatric pulmonology, radiology, infectious diseases and microbiology. Published international guidelines have also been consulted.

Guideline for the management of upper respiratory tract infections

INTRODUCTION

Inappropriate use of antibiotics for upper respiratory tract infections (URTIs), many of which are viral, adds to the burden of antibiotic resistance. Antibiotic resistance is increasing in Streptococcus pneumoniae, responsible for most cases of acute otitis media (AOM) and acute bacterial sinusitis (ABS).

METHOD

The Infectious Diseases Society of Southern Africa held a multidisciplinary meeting to draw up a national guideline for the management of URTIs. Background information reviewed included randomised controlled trials, existing URTI guidelines and local antibiotic susceptibility patterns. The initial document was drafted at the meeting. Subsequent drafts were circulated to members of the working group for modification. The guideline is a consensus document based upon the opinions of the working group.

OUTPUT

Penicillin remains the drug of choice for tonsillopharyngitis. Single-dose parenteral administration of benzathine penicillin is effective, but many favour oral administration twice daily for 10 days. Amoxycillin remains the drug of choice for both AOM and ABS. A dose of 90 mg/ kg/day is recommended in general, which should be effective for pneumococci with high-level penicillin resistance (this is particularly likely in children < or = 2 years of age, in day-care attendees, in cases with prior AOM within the past 6 months, and in children who have received antibiotics within the last 3 months). Alternative antibiotic choices are given in the guideline with recommendations for their specific indications. These antibiotics include amoxycillin-clavulanate, some cephalosporins, the macrolide/azalide and ketolide groups of agents and the respiratory fluoroquinolones.

CONCLUSION

The guideline should assist rational antibiotic prescribing for URTIs. However, it should be updated when new information becomes available from randomised controlled trials and surveillance studies of local antibiotic susceptibility patterns.

HIV and childhood tuberculosis: the way forward

Tuberculosis has been a major cause of morbidity and mortality in under-resourced communities. By causing progressive immunodeficiency, the human immunodeficiency virus (HIV) increases susceptibility to tuberculosis in an already vulnerable community. Similarities in clinical presentation and radiological appearance contribute to diagnostic difficulties, as even in the absence of HIV childhood tuberculosis is not easy to diagnose. The majority of studies thus far have been descriptive and often cross-sectional, but have defined the extent of this complex interaction. There is now a need to undertake prospective diagnostic, therapeutic and prevention studies. An emerging concern is how to integrate antiretroviral with anti-tuberculosis treatment and to explore whether lessons learned in tuberculosis can support antiretroviral therapy. Interactions between therapies for both conditions also need careful study.

Severe lower respiratory tract infections associated with human parainfluenza viruses 1-3 in children infected and noninfected with HIV type 1

The aim of this study was to compare the clinical course of severe lower respiratory tract infections associated with human parainfluenza virus types 1-3 (HPIV 1-3) in hospitalised children infected with the human immunodeficiency virus type 1 (HIV-1) versus that in hospitalised children not infected with HIV-1. Children were enrolled prospectively as part of a broader study that evaluated the aetiology of lower respiratory tract infections in HIV-1-infected and -noninfected children from March 1997 through March 1999. HPIV types 1-3 were isolated from nasopharyngeal aspirate samples that were analysed using immunofluorescein monoclonal antibody assays. Thirty percent (24 of 80) of the children from whom HPIV was isolated were infected with HIV-1. Sixty-six percent (47 of 62) and 22% (14 of 62) of the HPIV isolates that were typed were subtypes 3 and 1, respectively. The clinical presentation of severe lower respiratory tract infection was similar in both HIV-1-infected and -noninfected children, except that the former were less likely to have wheezing (4.2% vs. 28.6%, P=0.01). Furthermore, the duration of hospitalisation was longer in HIV-1-infected children than in HIV-1-noninfected children (median 11.5 days [range 1-15 days] vs. median 7.5 days [range 1-22 days]; P=0.02), and mortality was higher (5 of 24 [20.8%] infected children vs. 0 of 56 noninfected children; P=0.001). Importantly, four of five (80%) of the HIV-1-infected children who died had other concurrent illnesses or predisposing factors for severe HPIV-associated disease. HPIV-associated lower respiratory tract infection causes greater morbidity and mortality in HIV-1-infected children than in HIV-1-noninfected children; however, this may be due to other concurrent illnesses in HIV-1-infected children.

Impact of human immunodeficiency virus type 1 infection on the epidemiology and outcome of bacterial meningitis in South African children

OBJECTIVE

To define the impact that the human immunodeficiency virus type 1 (HIV-1) epidemic has had on the burden and outcome of bacterial meningitis in an area with a high prevalence of pediatric HIV-1 infection.

METHODS

Children less than 12 years of age with proven or suspected bacterial meningitis were enrolled in this study between March 1997 and February 1999, and their hospital records were retrospectively reviewed for clinical data.

RESULTS

Sixty-two (42.2%) of the 147 children tested for HIV-1 infection were infected. Streptococcus pneumoniae (Pnc) exceeded Haemophilus influenzae type b (Hib) as the most important cause of meningitis in HIV-1-infected (74.2% vs. 12.9%, respectively) compared with uninfected children (29.4% vs. 42.3%, respectively, P less than 10(-5)). The estimated relative risk of Pnc meningitis was greater in HIV-1-infected than in uninfected children under 2 years of age (relative risk [RR] = 40.4; 95% confidence intervals [CI] = 17.7-92.2). Overall, HIV-1-infected children had a higher rate of mortality than uninfected children (30.6% vs. 11.8%, respectively, P = 0.01), and in particular, HIV-1-infected children with Pnc meningitis (60.8% vs. 36.0%, respectively, P = 0.04) had a poorer outcome.

CONCLUSIONS

Streptococcus pneumoniae has exceeded Hib as the most important pathogen causing bacterial meningitis in HIV-1-infected compared with uninfected children. Effective vaccination against Hib and Pnc should be evaluated to reduce the overall burden of bacterial meningitis in HIV-1-infected children.

Differing manifestations of respiratory syncytial virus-associated severe lower respiratory tract infections in human immunodeficiency virus type 1-infected and uninfected children

BACKGROUND

Respiratory syncytial virus (RSV) causes increased morbidity and mortality in immunocompromised children. The outcome of RSV-associated lower respiratory tract infections (LRTI) in HIV-infected children, is less well described.

METHODS

Children from a prospective study evaluating the etiology of

Impact of human immunodeficiency virus type 1 on the disease spectrum of Streptococcus pneumoniae in South African children

BACKGROUND

HIV-infected children are at increased risk of developing invasive Streptococcus pneumoniae disease.

OBJECTIVE

To determine the impact of the HIV epidemic on the epidemiology of invasive pneumococcal disease in hospitalized African children.

METHODS

Children <12 years of age with invasive pneumococcal disease were enrolled between March, 1997, and February, 1999.

RESULTS

The seroprevalence of HIV was 64.9% (146 of 225). In children with pneumococcal isolates from serogroups 6, 9, 14, 19 or 23 (pediatric serogroups), pneumonia and pneumonia with concurrent meningitis was more common in HIV-infected children (P = 0.03 and P = 0.003, respectively), whereas septic shock occurred more often in HIV-uninfected children (P = 0.0003). The overall burden of severe invasive pneumococcal disease was 41.7 (95% confidence interval, 26.5 to 65.6) fold increased in HIV-infected compared with HIV-uninfected children. Reduced susceptibility to penicillin (45.91% vs. 27.9%, P = 0.009), trimethoprim-sulfamethoxazole (44.5% vs. 19.0%, P = 0.0002) and multiple drug resistance was more common in HIV-infected than in HIV-uninfected children (24.0% vs. 6.4%, P = 0.01), respectively. The increased burden of disease and reduced antibiotic susceptibility of pneumococcal isolates in HIV-infected children was because of a heightened susceptibility to disease caused by pediatric serogroups in these children than in HIV-uninfected children (P = 0.01). Although the case fatality rates did not differ between HIV-infected and -uninfected children, mortality in HIV-infected children with advanced AIDS (Stage C, 22 of 61; 36.1%) was greater than that in children with moderate AIDS (Stage B, 12 of 85; 14.1%, P = 0.002).

CONCLUSIONS

In children with invasive pneumococcal disease caused by the pediatric serogroups, HIV-infected children have more antibiotic-resistant isolates and have a different clinical presentation than do HIV-uninfected children.

Increased burden of respiratory viral associated severe lower respiratory tract infections in children infected with human immunodeficiency virus type-1

OBJECTIVES

To determine the burden of viral associated severe lower respiratory tract infections (SLRTI) in human immunodeficiency virus-infected (HIV+) and HIV-uninfected (HIV-) urban black South African children.

METHODS

Children with SLRTI aged 2 to 60 months were enrolled between March 1997 and March 1998. Monoclonal antibody immunofluorescent testing was performed on nasopharyngeal aspirates to detect respiratory syncytial virus (RSV), influenza A and B, parainfluenza 1-3, and adenovirus-specific antigens.

RESULTS

Of the 990 children studied, 44.6% were HIV+. The estimated burden of disease of viral associated SLRTI in children under 2 years was increased for RSV, influenza A/B viruses, parainfluenza 1-3 viruses, and adenovirus in children who were HIV+ compared with children who were HIV- (P <.001). Viral pathogens, however, were identified less frequently (15.7% vs 34.8%, P < 10(-5)) and bacterial pathogens more frequently (12.5% vs 5.8%, P <.0001) in children who were HIV+ than in children who were HIV- and had SLRTI. The seasonal peak for RSV in late summer-early autumn observed in children who were HIV- was less evident in children who were HIV+ (P =.02). Children who were HIV+ and had virus-associated SLRTI had a higher mortality rate (7. 5%) than did children who were HIV- (0%, P < 10(-3)).

CONCLUSIONS

The contribution of viral associated SLRTI differs between HIV+ and HIV- children. In HIV+ children in South Africa, RSV isolation is not limited by season.

Increased disease burden and antibiotic resistance of bacteria causing severe community-acquired lower respiratory tract infections in human immunodeficiency virus type 1-infected children

To improve the management of lower respiratory tract infections (LRTI) in human immunodeficiency virus type 1 (HIV-1)-infected children, we assessed the burden of disease, clinical outcome and antibiotic susceptibility of bacteria causing severe community-acquired LRTI in children. A prospective, descriptive study was performed in the pediatric wards at a secondary and tertiary care hospital in South Africa. Urban black children aged 2-60 months admitted with severe acute LRTI from March 1997 through February 1998 were enrolled. HIV-1 infection was present in 45.1% of 1215 cases of severe LRTI. Bacteremia occurred in 14.9% of HIV-1-infected and in 6.5% of HIV-1-uninfected children (P<.00001). The estimated relative incidence of bacteremic severe LRTI in children aged from 2 to 24 months were greater in HIV-1-infected than in -uninfected children for Streptococcus pneumoniae (risk ratio [RR], 42.9; 95% confidence interval [CI], 20.7-90.2), Haemophilus influenzae type b (RR, 21.4; 95% CI, 9.4-48.4), Staphylococcus aureus (RR, 97.9; 95% CI, 11.4-838.2) and Escherichia coli (RR, 49.0; 95% CI, 15.4-156). Isolation of Mycobacterium tuberculosis was also more common in HIV-1-infected than in -uninfected children (RR, 22.5; 95% CI, 13.4-37.6). In HIV-1-infected children, 60% of S. aureus and 85.7% of E. coli isolates were resistant to methicillin and trimethoprim-sulfamethoxazole, respectively. The case-fatality rates among HIV-1-infected children was 13.1%, and among HIV-1-uninfected children, 2.1% (adjusted odds ratio [AOR]; 6.52, 95% CI, 3.53-12.05; P<.00001). The changing spectrum of bacteria and antibiotic susceptibility patterns in HIV-1-infected children requires a reevaluation of the empirical treatment of community-acquired severe LRTI in children from developing countries with a high prevalence of childhood HIV-1 infection.

HIV-1 co-infection in children hospitalised with tuberculosis in South Africa

SETTING

Hospitals associated with the Department of Paediatrics at the University of the Witwatersrand, Johannesburg, South Africa.

OBJECTIVES

To define the prevalence of human immunodeficiency virus (HIV) co-infection and differences in clinical presentation between HIV-infected and non-infected hospitalised children with tuberculosis.

DESIGN

Children were prospectively enrolled between August 1996 and January 1997.

RESULTS

Of 161 children enrolled, 42% were HIV-infected, including 67/137 with pulmonary tuberculosis (PTB) and 1/24 with extra-pulmonary disease (EPTB). Positive microscopy or bacteriology did not differ by HIV status for children with either PTB or EPTB. Although age did not differ between HIV-infected and non-infected children with PTB, non-HIV-infected children with EPTB were significantly older than those with PTB only (median age 32 months vs 14.5 months, P = 0.004). Chronic weight loss, malnutrition and the absence of BCG scarring were more common in HIV-infected children with PTB. HIV-infected children were also more likely to show cavitation (P = 0.001) and miliary TB (P = 0.01) on chest X-ray. Reactivity to tuberculin (> or = 5 mm and > or = 10 mm in HIV-infected and non-infected children, respectively) was significantly lower in HIV-infected children, as were CD4+ lymphocyte levels. The mortality rate during the study was 13.4% in HIV-infected children compared with 1.5% in non-HIV-infected children (P = 0.03).

CONCLUSIONS

There is a high prevalence of HIV co-infection in children with TB. Progressive PTB and death are more common in HIV-infected children. Tuberculin skin testing is of limited use in screening for TB in HIV-infected children even when using a cut-point of > or = 5 mm.

Correlation between CD4+ lymphocyte counts, concurrent antigen skin test and tuberculin skin test reactivity in human immunodeficiency virus type 1-infected and -uninfected children with tuberculosis

BACKGROUND

HIV-infected children are at high risk of developing tuberculosis after infection by Mycobacterium tuberculosis. Emphasis is placed on tuberculin skin testing (TST) for diagnosing tuberculosis in children; however, its value in HIV-infected children is controversial.

OBJECTIVES

To determine whether concurrent antigen testing and/or CD4+ lymphocyte counts help in the interpretation of the TST in children with tuberculosis.

METHODS

Children eligible for the study were diagnosed as having tuberculosis on clinical criteria. CD4+ lymphocyte counts and delayed-type hypersensitivity (DTH) test, using the CMI Multitest were performed when tuberculosis was diagnosed.

RESULTS

One hundred thirty children were enrolled. Tuberculin reactivity was lower in HIV-infected children at all cutoff levels than in HIV-uninfected children (P < 0.0001). The positive predictive value of normal CD4+ lymphocyte counts in predicting tuberculin reactions of > or =5 mm (in HIV-1-infected) and > or =10 mm (in HIV-uninfected patients) were 50 and 80.3%, respectively (P < 0.0001). An intact DTH reaction to the CMI Multitest in predicting reactions of > or =5 mm and > or =10 mm to tuberculin in HIV-infected and -uninfected children were 55 and 76%, respectively (P < 0.001). Kwashiorkor was responsible for 53.3% of false-negative TST in HIV-uninfected children with normal CD4+ lymphocyte counts.

CONCLUSION

TST is of limited value as an adjunct in diagnosing tuberculosis in HIV-infected children. CD4+ lymphocyte counts and concurrent DTH testing are not useful for predicting tuberculin reactivity in HIV-infected patients with tuberculosis.

Emergence of drug resistance. Impact on bacterial meningitis

Antimicrobial resistance has emerged among the three major bacterial pathogens causing meningitis. Chloramphenicol resistance in the meningococcus recently has been described, and although intermediate penicillin resistance is common in some countries, the clinical importance of penicillin resistance in the meningococcus has yet to be established. Beta-lactamase-producing Haemophilus influenzae are relatively common, and chloramphenicol resistance is emerging. Third-generation cephalosporins are required to treat meningitis caused by these resistant strains. Pneumococcus resistance to penicillin and to chloramphenicol is widespread, and resistance to third-generation cephalosporins is found in many parts of the world. Correct management of these strains includes the addition of vancomycin or rifampin to therapy with third-generation cephalosporins.