Discrepant serological findings in SARS-CoV-2 PCR negative, hospitalised patients with fever and acute respiratory symptoms during the pandemic

BACKGROUND

COVID-19 serology has an evolving role in the diagnosis of SARS-CoV-2 infection. However, its use in hospitalised patients with acute respiratory symptoms remains unclear.

METHODS

Hospitalised patients with acute respiratory illness admitted to an isolation ward were recruited. All patients had negative nasopharyngeal swab polymerase chain reaction (PCR) for SARS-CoV-2. Serological studies using 4 separate assays (cPass: surrogate neutralising ELISA; Elecsys: N-antigen based chemiluminescent assay; SFB: S protein flow-based; epitope peptide-based ELISA;) were performed on stored plasma collected from patients during the initial hospital stay, and a convalescent visit 4-12 weeks later.

RESULTS

Of the 51 patients studied (aged 54, IQR 21-84; 62.7% male), no patients tested positive on the Elecsys or cPass assays. 5/51 patients had antibodies detected on B-cell Epitope Assay, and 3/51 had antibodies detected on SFB assay. These 8 patients with positive serological test to COVID-19 were more likely to have a high-risk occupation (p=0.039), bacterial infection (p=0.028) and neutrophilia (p=0.013) during their initial hospital admission.

CONCLUSION

Discrepant COVID-19 serological findings were observed amongst those with recent hospital admissions and bacterial infections. The positive serological findings within our cohort raise important questions about the interpretation of sero-epidemiology during the current pandemic. This article is protected by copyright. All rights reserved.

Low uptake of isoniazid window prophylaxis in patients exposed to a health-care worker with pulmonary tuberculosis in a paediatric ward

AIM

A nurse on a paediatric multidisciplinary ward was diagnosed with smear-positive pulmonary tuberculosis. Children <2 years old, immunocompromised, or >40 h of contact (n = 173) were contact-traced.

METHODS

Children received clinical review, chest X-ray, tuberculin skin test (TST; <5 years old) and/or an interferon-gamma release assay (Quantiferon TB-Gold, ≥5 years old). Infants <6 months old or children <5 years old screened <2 months from exposure were recommended isoniazid window prophylaxis (WP) until a repeat TST at 6 months old or 8-10 weeks after the last exposure to the index case, respectively. Empiric treatment for latent tuberculosis infection (LTBI) was individually considered for immunocompromised patients.

RESULTS

Of 173 children (135 immunocompetent, 38 immunocompromised), two were uncontactable, seven refused screening and two immunocompromised children excluded. Eight of 126 immunocompetent children were diagnosed with LTBI (initial TST positive n = 7, TST conversion n = 1); seven started isoniazid. Thirty-two of 36 immunocompetent children were recommended WP; 15 accepted (one non-compliant after 1 month). Six of seven immunocompromised children accepted empiric LTBI treatment due to severe immunosuppression/initial indeterminate Quantiferon TB-Gold result. Of 15 immunocompromised children offered WP, only five accepted.

CONCLUSIONS

There was high acceptance of screening but low uptake of isoniazid WP in high-risk children exposed to pulmonary tuberculosis. Perception of exposure risk and chemoprophylaxis should be explored further.

SARS-CoV-2 in migrant worker dormitories: Geospatial epidemiology supporting outbreak management

Background

Migrant worker dormitories—residential complexes where 10–24 workers share living spaces—account for the majority of cases of SARS-CoV-2 infection in Singapore. To prevent overspill of transmission to the wider population, starting in early April 2020, residents were confined to their dormitories while measures were put in place to arrest the spread of infection. This descriptive study presents epidemiological data for a population of more than 60 000 migrant workers living in two barracks-style and four apartment-style dormitories located in western Singapore from April 3 to June 10, 2020.

Methods

Our report draws from data obtained over the first 50 days of outbreak management in order to describe SARS-CoV-2 transmission in high-density housing environments. Cumulative counts of SARS-CoV-2 cases and numbers of housing units affected were analyzed to report the harmonic means of harmonic means of doubling times and their 95% confidence intervals (CI).

Results

Multiple transmission peaks were identified involving at least 5467 cases of SARS-CoV-2 infection across six dormitories. Our geospatial heat maps gave an early indication of outbreak severity in affected buildings. We found that the number of cases of SARS-CoV-2 infection doubled every 1.56 days (95% CI 1.29–1.96) in barracks-style buildings. The corresponding doubling time for apartment-style buildings was 2.65 days (95% CI 2.01–3.87).

Conclusions

Geospatial epidemiology was useful in shaping outbreak management strategies in dormitories. Our results indicate that building design plays an integral role in transmission and should be considered in the prevention of future outbreaks.

Establishing a New Normal for Hospital Care: A Whole of Hospital Approach to COVID-19

Singapore’s hospitals had prepared operations to receive patients (potentially) infected with SARS-CoV-2, planning various scenarios and levels of surge with a policy of isolating all confirmed cases as inpatients. The National University Hospital, adopted a whole of hospital approach to COVID-19 with three primary goals: zero hospital-acquired COVID-19, all patients receive timely necessary care, and maintenance of staff morale. These goals to date have been met. A large influx of COVID-19 cases emerged requiring a significant transformation of clinical and operational processes. Isolation room numbers almost tripled and dedicated COVID-19 cohort wards were established, elective care was postponed and Intensive Care Units were augmented with equipment and manpower. In the wake of the surge establishing a new normal for hospital care requires a considered balance of maintaining vigilance to detect endemic COVID-19, establishing contingency plans to ramp up in case of another surge, while returning to business as usual.

Scenarios to Manage the Demand for N95 Respirators for Healthcare Workers During the COVID-19 Pandemic

Background

By estimating N95 respirator demand based on simulated epidemics, we aim to assist planning efforts requiring estimations of respirator demand for the healthcare system to continue operating safely in the coming months.

Methods

We assess respiratory needs over the course of mild, moderate and severe epidemic scenarios within Singapore as a case study using a transmission dynamic model. The number of respirators required within the respiratory isolation wards and intensive care units was estimated over the course of the epidemic. We also considered single-use, extended-use and prolonged-use strategies for N95 respirators for use by healthcare workers treating suspected but negative (misclassified) or confirmed COVID-19 patients.

Results

Depending on the confirmed to misclassified case ratio, from 1:0 to 1:10, a range of 117.1 million to 1.1 billion masks are required for single-use. This decreases to 71.6–784.4 million for extended-use and 12.8–148.2 million for prolonged-use, representing a 31.8–38.9% and 86.5–89.1% reduction, respectively.

Conclusion

An extended-use policy should be considered when short-term supply chains are strained but planning measures are in place to ensure long-term availability. With severe shortage expectations from a severe epidemic, as some European countries have experienced, prolonged use is necessary to prolong supply.

Control and management of multidrug resistant Acinetobacter baumannii: A review of the evidence and proposal of novel approaches

Hospital-acquired infections are on the rise and are a substantial cause of clinical and financial burden for healthcare systems. While infection control plays a major role in curtailing the spread of outbreak organisms, it is not always successful. One organism of particular concern is Acinetobacter baumannii, due to both its persistence in the hospital setting and its ability to acquire antibiotic resistance. A. baumannii has emerged as a nosocomial pathogen that exhibits high levels of resistance to antibiotics, and remains resilient against traditional cleaning measures with resistance to Colistin increasingly reported. Given the magnitude and costs associated with hospital acquired infections, and the increase in multidrug-resistant organisms, it is worth re-evaluating our current approaches and looking for alternatives or adjuncts to traditional antibiotics therapies. The aims of this review are to look at how this organism is spread within the hospital setting, discuss current treatment modalities, and propose alternative methods of outbreak management.

Rapid publications risk the integrity of science in the era of COVID-19

BACKGROUND

Preprint manuscripts, rapid publications and opinion pieces have been essential in permitting the lay press and public health authorities to preview data relating to coronavirus disease 2019 (COVID-19), including the range of clinical manifestations and the basic epidemiology early on in the pandemic. However, the rapid dissemination of information has highlighted some issues with communication of scientific results and opinions in this time of heightened sensitivity and global concern.

MAIN TEXT

Rapid publication of COVID-19 literature through expedited review, preprint publications and opinion pieces are important resources for the medical scientific community. Yet the risks of unverified information loom large in times when the healthcare community is desperate for information. Information that has not been properly vetted, or opinion pieces without solid evidence, may be used to influence public health policy decisions. We discuss three examples of unverified information and the consequences in this time of high anxiety surrounding COVID-19.

CONCLUSIONS

In an era when information can be widely and swiftly disseminated, it is important to ensure that the scientific community is not an inadvertent source of misinformation. This will require a multimodal approach, with buy-in from editors, publishers, preprint servers, authors and journalists. The landscape of medical publications has changed, and a collaborative approach is required to maintain a high standard of scientific communications.

Responding to COVID-19: how an academic infectious diseases division mobilized in Singapore

BACKGROUND

On January 30, COVID-19 was declared a Public Health Emergency of International Concern-a week after Singapore's first imported case and 5 days before local transmission. The National University Hospital (NUH) is Singapore's third largest hospital with 1200 beds, heavy clinical workloads, and major roles in research and teaching.

MAIN BODY

With memories of SARS still vivid, there was an urgent requirement for the NUH Division of Infectious Diseases to adapt-undergoing major reorganization to face rapidly changing priorities while ensuring usual essential services and standards. Leveraging on individual strengths, our division mobilized to meet the demands of COVID-19 while engaging in high-level coordination, strategy, and advocacy. We present our experience of the 60 days since the nation's first case. During this time, our hospital has managed 3030 suspect cases, including 1300 inpatients, 37 confirmed cases, and overseen 4384 samples tested for COVID-19.

CONCLUSION

Complex hospital adaptations were supported by an unprecedented number of workflows and coordination channels essential to safe and effective operations. The actions we describe, aligned with international recommendations and emerging evidence-based best practices, may serve as a framework for other divisions and institutions facing the spread of COVID-19 globally.

Responding to the COVID-19 pandemic: The role of occupational health services in a tertiary hospital in Singapore

With coronavirus disease 2019 declared a Public Health Emergency of International Concern on 30 January 2020, occupational health services in a tertiary hospital in Singapore stepped up via a three-pronged approach, namely, protection of individual staff, protection of staff workforce, and prevention of nosocomial spread so as to support business continuity plans. Despite the multiple new challenges brought by the COVID-19 pandemic, the hospital's occupational health services were able to adapt and keep all employees and patients safe with strong support from senior management and close collaboration with various departments.

Distinguishing Zika and Dengue Viruses through Simple Clinical Assessment, Singapore

Dengue virus and Zika virus coexist in tropical regions in Asia where healthcare resources are limited; differentiating the 2 viruses is challenging. We showed in a case–control discovery cohort, and replicated in a validation cohort, that the diagnostic indices of conjunctivitis, platelet count, and monocyte count reliably distinguished between these viruses.

Diagnosis and treatment of Clostridium difficile in adults: a systematic review

IMPORTANCE

Since 2000, the incidence and severity of Clostridium difficile infection (CDI) have increased.

OBJECTIVE

To review current evidence regarding best practices for the diagnosis and treatment of CDI in adults (age ≥ 18 years).

EVIDENCE REVIEW

Ovid MEDLINE and Cochrane databases were searched using keywords relevant to the diagnosis and treatment of CDI in adults. Articles published between January 1978 and October 31, 2014, were selected for inclusion based on targeted keyword searches, manual review of bibliographies, and whether the article was a guideline, systematic review, or meta-analysis published within the past 10 years. Of 4682 articles initially identified, 196 were selected for full review. Of these, the most pertinent 116 articles were included. Clinical trials, large observational studies, and more recently published articles were prioritized in the selection process.

FINDINGS

Laboratory testing cannot distinguish between asymptomatic colonization and symptomatic infection with C difficile. Diagnostic approaches are complex due to the availability of multiple testing strategies. Multistep algorithms using polymerase chain reaction (PCR) for the toxin gene(s) or single-step PCR on liquid stool samples have the best test performance characteristics (for multistep: sensitivity was 0.68-1.00 and specificity was 0.92-1.00; and for single step: sensitivity was 0.86-0.92 and specificity was 0.94-0.97). Vancomycin and metronidazole are first-line therapies for most patients, although treatment failures have been associated with metronidazole in severe or complicated cases of CDI. Recent data demonstrate clinical success rates of 66.3% for metronidazole vs 78.5% for vancomycin for severe CDI. Newer therapies show promising results, including fidaxomicin (similar clinical cure rates to vancomycin, with lower recurrence rates for fidaxomicin, 15.4% vs vancomycin, 25.3%; P = .005) and fecal microbiota transplantation (response rates of 83%-94% for recurrent CDI).

CONCLUSIONS AND RELEVANCE

Diagnostic testing for CDI should be performed only in symptomatic patients. Treatment strategies should be based on disease severity, history of prior CDI, and the individual patient's risk of recurrence. Vancomycin is the treatment of choice for severe or complicated CDI, with or without adjunctive therapies. Metronidazole is appropriate for mild disease. Fidaxomicin is a therapeutic option for patients with recurrent CDI or a high risk of recurrence. Fecal microbiota transplantation is associated with symptom resolution of recurrent CDI but its role in primary and severe CDI is not established.

Seasonal influenza A (H1N1) infection in early pregnancy and second trimester fetal demise

A second trimester fetal demise followed influenza-like illness in early pregnancy. Influenza A virus (H1N1) was identified in maternal and fetal tissue, confirming transplacental passage. These findings suggested a causal relationship between early exposure and fetal demise. Management of future influenza outbreaks should include evaluation of products of conception associated with fetal loss.