SARS-CoV-2 viral RNA load dynamics in the nasopharynx of infected children.

It is important to understand the temporal trend of the paediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load to estimate the transmission potential of children in schools and communities. We determined the differences in SARS-CoV-2 viral load dynamics between nasopharyngeal samples of infected asymptomatic and symptomatic children. Serial cycle threshold values of SARS-CoV-2 from the nasopharynx of a cohort of infected children were collected for analysis. Among 17 infected children, 10 (58.8%) were symptomatic. Symptomatic children, when compared to asymptomatic children, had higher viral loads (mean cycle threshold on day 7 of illness 28.6 vs. 36.7, P = 0.02). Peak SARS-CoV-2 viral loads occurred around day 2 of illness in infected children. Although we were unable to directly demonstrate infectivity, the detection of significant amount of virus in the upper airway of asymptomatic children suggest that they have the potential to shed and transmit SARS-CoV-2. Our study highlights the importance of contact tracing and screening for SARS-CoV-2 in children with epidemiological risk factors regardless of their symptom status, in order to improve containment of the virus in the community, including educational settings.

Reliability of acute illness dihydrorhodamine-123 testing for chronic granulomatous disease.

BACKGROUND: Dihydrorhodamine (DHR) flow cytometric analysis is used to evaluate granulocyte oxidative bursts and is the test of choice for the diagnosis of chronic granulomatous disease (CGD). We present the clinical and DHR test profiles of five subjects assessed during and after acute illness. METHODS: This was a retrospective report of the findings of five out of a total of one hundred and seventeen patients, whose blood was sent to the laboratory for dihydrorhodamine-123 flow cytometry testing between January 2005 and December 2010. Using whole blood technique and stimulation using phorbol myristate acetate, the results of DHR were expressed as stimulation index and coefficient of variation of histograms of stimulated cells and compared with healthy controls. DHR tests were repeated when the patients had recovered and were clinically well. RESULTS: These five patients showed abnormal DHR test results during their acute illness, with a stimulation index (SI) lower (p = 0.009) and coefficient of variation (CV) higher (p = 0.009) than controls. The DHR profiles repeated when patients had recovered showed normalization of tests with no significant difference for SI (p = 0.602) and CV (p = 0.917) compared to controls. Wilcoxon Signed Rank tests showed a significant improvement in SI (p = 0.043) and CV (p = 0.043) upon recovery. On follow up, all five patients were well, with no further severe or atypical infections. CONCLUSIONS: DHR may be transiently abnormal during acute illness, and may therefore not be reliable when assessed during an acute illness. If these subjects had CGD, it would be of a hypomorphic variant that has not previously been described.

Correlations between clinical illness, respiratory virus infections and climate factors in a tropical paediatric population.

Weekly (August 2003-December 2008) numbers of five common paediatric diseases and the incidence of respiratory viruses were obtained from a children's hospital in Singapore and correlated with climate data using multivariate time-series techniques. Upper respiratory tract infections were positively correlated with the incidences of influenza A, B, respiratory syncytial virus (RSV) and parainfluenza viruses (types 1-3 combined). Lower respiratory tract infections were positively correlated with only the incidence of RSV. Both upper and lower respiratory tract infections were negatively correlated with relative humidity. Asthma admissions were negatively correlated with maximum temperature and positively correlated with the incidence of influenza B and increasing hours of sunshine. Although sporadic cases of adenovirus infection were identified, not enough cases were available for a more detailed analysis. Gastroenteritis and urinary tract infections, included as control diseases, were not correlated significantly with any climate parameters. These correlations are compatible with current understanding of respiratory virus survival under certain climate conditions and may assist the prediction of disease burdens and hospital resource planning in such tropical environments.

Routine antiseptic baths and MRSA decolonization: diverse approaches across Singapore's acute-care hospitals.

To determine the variation in practices on meticillin-resistant Staphylococcus aureus (MRSA) surveillance and management of MRSA-colonized patients amongst 17 acute healthcare facilities in Singapore, the Ministry of Health convened a sharing session with Infection Prevention and Control Leads. All hospitals practised close to universal MRSA entry swabbing in keeping with national policy. There were, however, major variations in the response to both positive and negative surveillance swabs across facilities including the role of routine antiseptic bathing and MRSA decolonization. Most undertaking decolonization considered its role to be in 'bioburden reduction' rather than longer-term clearance.

Invasive paediatric Elizabethkingia meningoseptica infections are best treated with a combination of piperacillin/tazobactam and trimethoprim/sulfamethoxazole or fluoroquinolone.

OBJECTIVES: Elizabethkingia meningoseptica is a multi-drug-resistant organism that is associated with high mortality and morbidity in newborn and immunocompromised patients. This study aimed to identify the best antimicrobial therapy for treating this infection. METHODS: A retrospective descriptive study was conducted from 2010 to 2017 in a tertiary paediatric hospital in Singapore. Paediatric patients aged 0 to 18 years old with a positive culture for E. meningoseptica from any sterile site were identified from the hospital laboratory database. The data collected included clinical characteristics, antimicrobial susceptibility and treatment, and clinical outcomes. RESULTS: Thirteen cases were identified in this study. Combination therapy with piperacillin/tazobactam and trimethoprim/sulfamethoxazole or a fluoroquinolone resulted in a cure rate of 81.8  %. The mortality rate was 15.4  % and neurological morbidity in patients with bacteraemia and meningitis remained high (75 %). CONCLUSIONS: Treatment with combination therapy of piperacillin/tazobactam and trimethoprim/sulfamethoxazole or a fluroquinolone was effective in this study, with low mortality rates being observed.

Comparative seroepidemiology of pertussis, diphtheria and poliovirus antibodies in Singapore: waning pertussis immunity in a highly immunized population and the need for adolescent booster doses.

BACKGROUND: We assessed the seroepidemiology of pertussis, diphtheria and poliovirus antibodies in a cohort of highly immunized children, together with the burden of these diseases in Singapore. METHODS: Hospital residual sera collected between August 2008 and July 2010 from 1200 children aged 1-17 years were tested for the prevalence of IgG antibodies against Bordetella pertussis, diphtheria toxoid, and all three poliovirus types by enzyme-linked immunosorbent assays. RESULTS: We found an overall seroprevalence of 99.4% (95% CI 98.8-99.7%) for diphtheria, and 92.3% (95% CI 90.6-93.6%) for poliomyelitis, along with no indigenous cases of these diseases since 1993. However, the seroprevalence for pertussis was 60.8% (95% CI 58.0-63.5%) only. Among the subjects who had completed three doses of pertussis vaccination by the age of 2 years (n=1092), the pertussis seroprevalence was 85.0% (95% CI 79.7-89.2%) in those who received the last vaccination within a year before the study, and it decreased to 75.0% (95% CI 64.5-83.2%) and 63.1% (95% CI 50.9-73.8%) in those who had the last vaccination 1 year and 2 years before the study, respectively. The seroprevalence remained at about 50% for those whose last pertussis vaccination was administered 4 years and longer before the study. CONCLUSIONS: The high seroprevalence for poliomyelitis and diphtheria confer solid herd immunity to eliminate these diseases in Singapore. In contrast, immunity against pertussis waned considerably over time, and routine boosters should be given to adolescents to ensure sustained immunity against pertussis.