COVID-19 antibody testing: from hype to immunological reality

The potential role for serological tests in the current COVID-19 pandemic has generated very considerable recent interest across many sectors worldwide, inter alia pathologists seeking additional weapons for their armoury of diagnostic tests; epidemiologists seeking tools to gain seroprevalence data that will inform improved models of the spread of disease; research scientists seeking tools to study the natural history of COVID-19 disease; vaccine developers seeking tools to assess vaccine efficacy in clinical trials; and companies and governments seeking tools to aid return-to-work decision-making. However, much of the local debate to date has centred on questions surrounding whether regulatory approval processes are limiting access to serological tests, and has not paused to consider the intrinsically limiting impact of underlying fundamental biology and immunology on where and how different COVID-19 serological tests can usefully be deployed in the response to the current pandemic. We review, from an immunological perspective, recent experimental evidence on the time-dependency of adaptive immune responses following SARS-CoV-2 infection and the impact of this on the sensitivity and specificity of COVID-19 antibody tests made at different time points post infection. We interpret this scientific evidence in terms of mooted clinical applications for current COVID-19 antibody tests in identifying acute infections, in confirming recent or past infections at the individual and population level, and in detecting re-infection and protective immunity. We conclude with guidance on where current COVID-19 antibody tests can make a genuine impact in the pandemic

The mechanics of setting up a COVID-19 response: Experiences of the COVID-19 epidemic from Groote Schuur Hospital, Cape Town, South Africa

The COVID-19 pandemic has challenged the provision of healthcare in ways that are unprecedented in our lifetime. Planning for the sheer numbers expected during the surge has required public hospitals to de-escalate all non-essential clinical services to focus on COVID-19. Western Cape Province was the initial epicentre of the COVID-19 epidemic in South Africa (SA), and the Cape Town metro was its hardest-hit geographical region. We describe how we constructed our COVID-19 hospital-wide clinical service at Groote Schuur Hospital, the University of Cape Town's tertiary-level teaching hospital. By describing the barriers and enablers, we hope to provide guidance rather than a blueprint for hospitals elsewhere in SA and in low-resource countries that face similar challenges now or during subsequent waves

Emergency Peripartum Hysterectomies at Muhimbili National Hospital; Tanzania: A Review of Cases from 2003 to 2007

Abstract:A retrospective review of all cases of emergency peripartum hysterectomy performed between January 1; 2003 and December 31; 2007 at Muhimbili National Hospital was done to determine the incidence; indications and complications; background characteristics; antenatal care attendance; referral status; and maternal and foetal outcomes. There were 55;152 deliveries during the study period and 165 cases of emergency peripartum hysterectomy; giving the incidence of emergency peripartum hysterectomy of 3 per 1000 deliveries. The main indication was uterine rupture (79) followed by severe post-partum haemorrhage due to uterine atony (12.7). The case fatality rate was 10.3 where as perinatal mortality rate was 7.7 per 1000 deliveries. The common complication identified intraoperatively was severe haemorrhage which accounted for 39.4 where as intensive care unit admissions (14.4) and febrile morbidity (12.4) were common after the operation. Blood was ordered in all cases but in 31 cases it was indicated that it was not available. Seventy nine patients received blood transfusion with the maximum number of units given to one patient being eight. Twenty two patients were given fresh frozen plasma (FFP); the median number of units given was two (range = 1- 6). In conclusion; emergency peripartum hysterectomy is a life saving procedure and very common at MNH. The most common indication was ruptured uterus followed by severe postpartum haemorrhage. More than half of the patients underwent emergency peripartum hysterectomy were referred from other health facilities with ruptured or suspected ruptured uterus. The procedure was associated with unacceptably high maternal and perinatal morbidity and mortality

Accuracy in Diagnosis of Postpartum Haemorrhage Using Visual Estimation of Blood Loss versus Change in Haematocrit in a Tertiary Teaching Hospital in Tanzania

Abstract:Postpartum haemorrhage is the leading cause of maternal death in the developing country and yet is poorly diagnosed due to inaccurate measurement of blood loss following delivery. A study was carried out at Muhimbili National Hospital (MNH) Tanzania between October 2005 and January 2006 to determine the accuracy of visual estimation of blood loss (VEBL) in comparison to laboratory measurement of blood loss in diagnosis of primary postpartum haemorrhage (PPH). A total of 426 pregnant women who were in active phase of labour were recruited and their venous blood was drawn for estimation of haematocrit before delivery and 12 hours thereafter. Active management of third stage of labour was conducted by giving 10IU of oxytocin (intramuscularly or intravenously) and this was followed by visual estimation of blood loss. The proportion of patients who developed PPH was then determined by both methods. The mean duration of third stage of labour was 8.3 minutes and mean blood loss was 164.9ml. The prevalence of PPH was 8.9 and 16.2 by VEBL and changes in haematocrit; respectively. Change in haematocrit in diagnosis of PPH was found to be more accurate; specific with high positive predictive values compared to VEBL. The need for additional uterotonics was 5.8 and the commonest labour complications associated with PPH were second degree tear; retained placenta and EUA for continued bleeding. In conclusion; VEBL using calibrated vessel will increase accuracy where conventional method using non calibrated method is used for diagnosis of PPH. Service providers working in labour wards need to be trained on how to estimate blood loss using simulated methods so as to increase their long term memory and accuracy in diagnosis of post-partum haemorrhage; hence provision of immediate intervention

Increase in the Detection Rate of Viral and Parasitic Enteric Pathogens among Egyptian Children with Acute Diarrhea

Introduction: Acute diarrhea continues to be a major cause of morbidity and mortality in children from developing countries. Determination of the frequency of diarrhea in an area; along with the proportion of disease caused by specific enteric agents of different origins; is considered the first step in controlling diarrheal diseases. Methodology: From 2005 to 2007; a hospital-based surveillance was conducted in two locations in Egypt to determine the causes of acute diarrhea in children younger than 5-years seeking treatment. Five additional enteric viral and parasitic pathogens were tested using commercially-available enzyme immunoassays (EIA) to re-evaluate the prevalence of diarrheal pathogens in undiagnosed cases.Results: Adenovirus; astrovirus; norovirus and G. lamblia were detected as the sole pathogen in 2 (n=34); 3 (n=56); 9 (n=191) and 7 (n=146) of the cases; respectively. E. histolytica was never detected as the sole pathogen. The percentage of diarrheal cases with a known cause increased significantly; from 48 (n=1;006) to 74 (n=1;568) (P0.0001). Conclusion: In our study; the incorporation of immunoassays yielded useful data in identifying pathogens in previously pathogen-negative diarrhea cases

Burden of Aeromonas Hydrophila Associated Diarrhea among Children Younger than 2 Years in Rural Egyptian Community

Introduction: Between 2004 and 2007; a birth cohort of Egyptian children was analysed to evaluate the epidemiology of enteric diseases. Methodology: A stool sample was collected from the study children every two weeks as well as whenever they experienced diarrhea. Samples were tested for routine bacterial pathogens as well as enteropathogenic viruses and parasites. A secondary goal of the study was to evaluate the burden of less commonly reported pathogens including Aeromonas hydrophila. Results: Of the 348 study subjects; 79 had A. hydrophila isolated from their stool at some point during the study. Thirty-six children had exclusively symptomatic (S) infections while 33 had exclusively asymptomatic (AS) infections. However; 10 children had both S and AS infections. Among symptomatic cases; A. hydrophila was the sole pathogen isolated 36of the time. An important aspect of A. hydrophila associated diarrhea was the high level of resistance to cephalosporins. Conclusion: Although relatively uncommon; A. hydrophila was found to be associated with diarrhea among children living in Egypt and was frequently multi-drug resistant

Brain abscesses - the Groote Schuur experience; 1993 - 2003 : neurosurgery

Objective. To review management and outcome of patients with brain abscess treated at Groote Schuur Hospital (GSH) between 1993 and 2003. Patients and methods. Case notes; radiological results and laboratory records were reviewed retrospectively for 121 patients at GSH who underwent a neurosurgical procedure for treatment of a brain abscess between 1993 and 2003. Patients not treated surgically were excluded. Follow-up with serial computed tomography (CT) scans; erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels and the temperature chart were used to determine the duration of parenteral antibiotic treatment and the need for repeat surgical evacuation of pus by either aspiration or excision of the capsule. Results. The mean patient age was 33 years; with a male-to-female ratio of 5:1. Headache; depressed level of consciousness and pyrexia were the commonest presenting symptoms. Other symptoms included seizures and hemiparesis. The frontal lobe was the commonest site (44); the majority of abscesses occurred as a result of infection following trauma. Mastoiditis (21) and sinusitis (8) were the second and third most common causes. Organisms were identified in 81of cases; polymicrobial infections occurred in half of these. Thirty-three different organisms were identified; the majority of which were Gram-positive bacteria. Anaerobes were present in 23; while methicillin-resistant Staphylococcus aureus was identified in 1 patient. Nocardia was seen in 3 patients; 2 of whom were diabetic. The average duration of parenteral antibiotic therapy was 15 and 19 days for excision and aspiration respectively. Accurate ESR records were available in 75of cases; with a positive predictive value in 81; while CRP (in use since 1999) was helpful in 92of cases. Outcome. Sixteen patients (13) died; 12 of whom had been admitted with a Glasgow Coma Score (GCS) of less than 4T/15. Thirteen patients developed epilepsy. On discharge; patients continued to take oral antibiotics for another 4 weeks; at the end of which they were reviewed at the neurosurgery outpatient department. Conclusion. Compared with previous studies from this hospital; mortality and morbidity have been diminishing progressively. GCS at the time of admission remains the most important prognostic factor