Carriage of Haemophilus influenzae in Cape Town children

Little is known about the epideIDiology of Haemophilus influenzae infections in South Africa. This study was designed to determine the prevalence, serotype distribution, antimicrobial susceptibility pattern and effect of age and hospitalisation on the carriage of H. influenzae in 322 Cape Town children.The overall and type b specific carriage rates in normal children (N =107) were 45,8% and 4,7% respectively. The yield following nasopharyngeal culture was twice that following throat culture (P < 0,001). Children hospitalised with tuberculosis (N =62) had significantly greater carriage rates, 66,1% and 37,1% respectively (P =0,02). Institutionalised mentally handicapped children (N =77) and children with tuberculosis attending an outpatient clinic (N =76) had lower carriage rates (P < 0,02). Antimicrobial resistance was a major problem only in children hospitalised with tuberculosis (rifampicin 100%, penicillin 43,9%, erythromycin 85,4%, co-trimoxazole 82,9%). This universal resistance to rifampicin has not been reported previously. There was no difference in the mean age of children with positive or negative cultures, with the exception of those hospitalised with tuberculosis. In this group children infected with type b were much younger (mean 19,7 months) than those with other and non-typeableinfections (32,1 months) and the non-infected(50,1 months) (P =0,04). Duration of hospitalisation or outpatient therapy in the patients with tuberculosis did not influence carriage rates.We conclude that carriage of H. influenzae in normal children is similar to that reported from other countries and that carriage, particularly of type b, in children hospitalised with tuberculosis was of significance and probably contributed to an outbreak of multi-resistant invasive H. influenzae disease in this group

Conductivity in quasi two-dimensional systems

The conductivity in quasi two-dimensional systems is calculated using the quantum kinetic equation. Linearizing the Lenard-Balescu collision integral with the extension to include external field dependences allows one to calculate the conductivity with diagrams beyond the GW approximation including maximally crossed lines. Consequently the weak localization correction as an interference effect appears here from the field dependence of the collision integral (the latter dependence sometimes called intra-collisional field effect). It is shown that this weak localization correction has the same origin as the Debye-Onsager relaxation effect in plasma physics. The approximation is applied to a system of quasi two-dimensional electrons in hetero-junctions which interact with charged and neutral impurities and the low temperature correction to the conductivity is calculated analytically. It turns out that the dynamical screening due to charged impurities leads to a linear temperature dependence, while the scattering from neutral impurities leads to the usual Fermi-liquid behavior. By considering an appropriate mass action law to determine the ratio of charged to neutral impurities we can describe the experimental metal-insulator transition at low temperatures as a Mott-Hubbard transition.Comment: 7 pages 7 pages appendix 11 figure

The 1992 measles epidemic in Cape Town - a changing epidemiological pattern

Over the last 6 years there has been a decline in the incidence of measles in Cape Town. However, during August 1992 an outbreak occurred, with cases reported at many schools in children presumably immunised. The objectives of this study were to characterise the epidemic in Cape Town and to determine possible reasons for the outbreak. The investigation consisted of two components - a description of the epidemic and an investigation of an outbreak at one primary school. Results indicate that during the last 4 months of the year, 757 cases were notified in Cape Town, com.pared with 144 in the first 8 months. The epidemic affected mainly white and coloured children over 5 years of age (P < 0,001). In contrast, during the period before the epidemic most cases occurred in black children and in those aged less than 1 year (P < 0,001). There was no significant increase in hospitalised cases. Investigation of the outbreak at one school revealed that the attack rate was 7,6% (25/329 children). Immunisation coverage (at least one dose of any measles vaccine) was 91% and vaccine efficacy was estimated to be 79% (95% Cl 55 - 90); it was highest for monovalent measles (100%) and lowest for measles-mumps-rubella (74%). The epidemiology of measles in Cape Town has thus changed as evinced in this epidemic, with an increase in the number of cases occurring in older, previously vaccinated children. The possible reasons for this include both primary and secondary vaccine failure. To prevent epidemics of this nature, immediate reimmunisation of all children at schools where outbreaks were identified is recommended and, in the long term, reimmunisation of all children before they start school should be considered

Assessment of humoral and cell-mediated immune responses to pertussis vaccination: A systematic review protocol

Introduction Globally, some studies show a resurgence of pertussis. The risks and benefits of using whole-cell pertussis (wP) or acellular pertussis (aP) vaccines in the control of the disease have been widely debated. Better control of pertussis will require improved understanding of the immune response to pertussis vaccines. Improved understanding and assessment of the immunity induced by pertussis vaccines is thus imperative. Several studies have documented different immunological outcomes to pertussis vaccination from an array of assays. We propose to conduct a systematic review of the different immunological assays and outcomes used in the assessment of the humoraland cell-mediated immune response following pertussis vaccination. Methods and analysis The primary outcomes for consideration are quality and quantity of immune responses (humoral and cell-mediated) post-pertussis vaccination. Of interest as secondary outcomes are types of immunoassays used in assessing immune responses post-pertussis vaccination, types of biological samples used in assessing immune responses post-pertussis vaccination, as well as the types of antigens used to stimulate these samples during post-pertussis vaccination immune response assessments. Different electronic databases (including PubMed, Cochrane, EBSCO Host, Scopus and Web of Science) will be accessed for peer-reviewed published and grey literature evaluating immune responses to pertussis vaccines between 1990 and 2019. The quality of included articles will be assessed using standardised risk and quality assessment tools specific to the study design used in each article. Data extraction will be done using a data extraction form. The extracted data will be analysed using STATA V.14.0 and RevMan V.5.3 software. A subgroup analysis will be conducted based on the study population, type of vaccine (wP or aP) and type of immune response (cell-mediated or humoral). Guidelines for reporting systematic reviews in the revised 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement will be used in this study. Ethics and dissemination Ethics approval is not required for this study as it is a systematic review. We will only make use of data already available in the public space. Findings will be reported via publication in a peer-reviewed journal and presented at scientific meetings and workshops. Trial registration number CRD42018102455.SCOPUS: re.jinfo:eu-repo/semantics/publishe

Consensus statement on the revised World Health Organization recommendations for BCG vaccination in HIV-infected infants

This document outlines the consensus agreement from the Union's BCG Working Group regarding BCG vaccination in HIV-infected infants, in response to recently revised World Health Organization (WHO) guidelines, which make HIV infection in infants a full contraindication to bacille Calmette-Guérin (BCG) vaccination. BCG is one of the most widely given vaccines globally and is safe in immunocompetent individuals. Recent evidence shows that HIV-infected infants who were routinely vaccinated with BCG at birth, when asymptomatic, and who later developed AIDS, are at high risk of developing disseminated BCG disease (estimated incidence 407-1300 per 100000). The document outlines requirements to implement selective BCG vaccination strategies in infants born to HIV-infected women and strategies to reduce the risk of vertical HIV transmission and disseminated BCG disease in infants. © 2008 The Union.Revie

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Twice weekly vs. daily chemotherapy for childhood tuberculosis

Background. Treating childhood tuberculosis places a large burden on health services, and ways of lessening this were sought. Methods. A randomized controlled trial was conducted to determine the effectiveness of fully intermittent twice weekly treatment for intrathoracic childhood tuberculosis and its effect on adherence to treatment, in comparison with daily (weekday) treatment. The setting was a district of Cape Town, South Africa, an area of high incident tuberculosis. We randomized 206 children with confirmed (4%), probable (94%) and suspected (2%) intrathoracic tuberculosis: 89 (median age, 25 months) received intermittent treatment; and 117 (median age, 28 months) received daily treatment. Intermittent treatment (twice weekly for 6 months) was isoniazid 15 mg/kg/dose, rifampin 15 mg/kg/dose and pyrazinamide 55 mg/kg/dose for 2 months, followed by isoniazid and rifampin only for 4 months. Daily treatment was isoniazid 10 mg/kg/day, rifampin 10 mg/kg/day and pyrazinamide 25 mg/kg/day on weekdays for 6 months. Results. At 6 months 97% of subjects were discharged, with treatment outcomes in the two groups equivalent at that time (P = 0.90) and at the 18- to 30- month follow-up. One relapse occurred in the twice weekly group (P = 0.25). Adherence was equivalent; 70 children (79%) on intermittent and 90 (77%) on daily treatment took 75% or more of the prescribed doses (P = 0.90). Nonadherence over the full course of therapy was significantly associated with nonadherence during the first month of treatment (P = 0.0002) and household crowding (P = 0.002). Conclusions. Six month fully intermittent antituberculosis treatment is an effective and acceptable alternative to daily treatment.Articl