Genetic association of COVID-19 severe versus non-severe cases by RNA sequencing in patients hospitalised in Hong Kong

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has caused extensive disruption of public health worldwide. There were reports of COVID-19 patients having multiple complications. This study investigated COVID-19 from a genetic perspective.

METHODS

We conducted RNA sequencing (RNA-Seq) analysis of respiratory tract samples from 24 patients with COVID-19. Eight patients receiving mechanical ventilation or extracorporeal membrane oxygenation were regarded as severe cases; the remaining 16 patients were regarded as non-severe cases. After quality control, statistical analyses were performed by logistic regression and the Kolmogorov-Smirnov test to identify genes associated with disease severity.

RESULTS

Six genes were associated with COVID-19 severity in both statistical tests, namely RPL15, BACE1-AS, CEPT1, EIF4G1, TMEM91, and TBCK. Among these genes, RPL15 and EIF4G1 played roles in the regulation of mRNA translation. Gene ontology analysis showed that the differentially expressed genes were mainly involved in nervous system diseases.

CONCLUSION

RNA sequencing analysis showed that severe acute respiratory syndrome coronavirus 2 infection is associated with the overexpression of genes involved in nervous system disorders.

Awareness, perceptions, and acceptance of human papillomavirus vaccination among parents in Hong Kong

INTRODUCTION

This study investigated the awareness, perceptions, and acceptance of human papillomavirus (HPV) vaccination for children among parents in Hong Kong. It also explored factors associated with, and differences in, vaccine acceptance and hesitancy between parents of girls and boys.

METHODS

Parents of boys or girls in Primary 5 to 6 were invited to participate in an online survey through an established health and lifestyle e-platform.

RESULTS

Overall, 851 parents completed the survey: 419 (49.2%) had daughters, 348 (40.9%) had sons, and 84 (9.9%) had children of both genders. Parents who enrolled their children into the Childhood Immunisation Programme were more likely to accept HPV vaccination (79.7% vs 33.7%, odds ratio [OR]=7.70; 95% confidence interval [CI]=5.39-11.01; P<0.001); parents of girls were more likely to accept than parents of boys (86.0% vs 71.8%, OR=2.40; 95% CI=1.67-3.46; P<0.001). Among parents of girls and boys, the main reasons for HPV vaccination acceptance were prevention of cancers (girls: 68.8% and boys: 68.7%), prevention of sexually transmitted diseases (girls: 67.3% and boys: 68.3%), and optimal timing before initiation of sexual activity (girls: 62.8% and boys: 59.8%). Vaccine hesitancy was mainly associated with concerns about serious side-effects (girls: 66.7% and boys: 68.0%) and the belief that their children were too young (girls: 60.0% and boys: 54.0%).

CONCLUSION

Parents in Hong Kong are hesitant about HPV vaccination for their sons. This barrier could be removed by providing information to correct vaccine safety misconceptions and offering a gender-neutral vaccination programme through the school-based Childhood Immunisation Programme.

Effects of strict public health measures on seroprevalence of anti-SARS-CoV-2 antibodies during pregnancy

INTRODUCTION

A substantial number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain asymptomatic throughout the course of infection. Nearly half of pregnant women with coronavirus disease 2019 (COVID-19) are asymptomatic upon diagnosis; these cases are not without risk of maternal morbidity. Here, we investigated the seroprevalence of anti-SARS-CoV-2 antibodies in an unselected sample of pregnant women in Hong Kong.

METHODS

This prospective cohort study included pregnant women who presented for routine Down syndrome screening (DSS) between November 2019 and October 2020; all women subsequently delivered at the booking hospitals. Serum antibodies against SARS-CoV-2 were analysed using a qualitative serological assay in paired serum samples taken at DSS and delivery for all participants.

RESULTS

In total, 1830 women were recruited. Six women (0.33%) were seropositive at the DSS visit; this seropositivity persisted until delivery. Of the six women, none reported relevant symptoms during pregnancy; one reported a travel history before DSS and one reported relevant contact history. The interval between sample collections was 177 days (range, 161-195). Among women with epidemiological risk factors, 1.79% with travel history, 50% with relevant contact history, and 0.77% with community SARS-CoV-2 testing history, were seropositive.

CONCLUSION

The low seroprevalence in this study suggests that strict public health measures are effective for preventing SARS-CoV-2 transmission. However, these measures cannot be maintained indefinitely. Until a highly effective therapeutic drug targeting SARS-CoV-2 becomes available, vaccination remains the best method to control the COVID-19 pandemic.

91Is rainfall associated with paediatric acute gastroenteritis in an affluent setting? A 21-Year Retrospective Investigation

Background

Although many literatures demonstrated heavy rainfall was associated with an increased risk of acute gastroenteritis via contaminated food and water, we hypothesized there is no association between rainfall and paediatric acute gastroenteritis in a setting with high-standard food and water hygiene.

Methods

Intestinal infection-related hospital admissions data during 1998-2018 for children under 5 years of age in Hong Kong were collected. Meteorological data were collected from the Hong Kong Observatory. A distributed lag nonlinear model was employed to examine the associations between meteorological factors and the risk of hospital admissions due to acute gastroenteritis.

Results

Rainfall did not exhibit a statistically significant association with the risk of paediatric admission due to acute gastroenteritis but low temperature, low and high relative humidity did. The risk was 6.3% higher (95% confidence interval: 0.3% to 12.6%) when temperature was at 15.1oC (i.e. the 5th percentile). The adjusted relative risk was statistically significantly higher when relative humidity was ≤73.0% or ≥ 84.0%.

Conclusions

Text: We suggest rainfall playing a minor role in disease transmission via contaminated food and water in affluent societies like Hong Kong. Instead, we speculate low temperature and humidity extremes have greater impact on transmission through increased stability and infectivity of enteric viruses.

Key messages

Weather plays a minor role in food and water contamination in affluent societies.

Low temperature and humidity extremes might improve survival of enteric viruses.

Faecal microbiota transplantation for treatment of recurrent or refractory Clostridioides difficile infection in Hong Kong

INTRODUCTION

Clostridioides difficile infection (CDI) is a leading cause of healthcare-associated infection globally, causing significant morbidity and mortality. Faecal microbiota transplantation (FMT) has emerged as a promising option for recurrent and refractory CDI. This study aimed to assess the safety, efficacy, and feasibility of FMT for CDI in Hong Kong.

METHODS

We conducted a single-centre, retrospective study for all consecutive cases of recurrent or refractory CDI who underwent FMT from 2013 to 2018. Clinical demographics, outcome, and safety parameters were collected.

RESULTS

A total of 24 patients with recurrent or refractory CDI (median age 70 years, interquartile range=45.0-78.3 years; 67% male) were included. Over 80% had been recently hospitalised or were long-term care facility residents. Faecal microbiota transplantation was delivered by feeding tube in 11 (45.8%), oesophagogastroduodenoscopy in eight (33.3%), and colonoscopy in six (25%) of the patients. Resolution of diarrhoea without relapse within 8 weeks was achieved in 21 out of 24 patients (87.5%) after FMT. No deaths occurred within 30 days. The FMT was well tolerated and no serious adverse events attributable to FMT were reported.

CONCLUSION

Our results confirm that FMT is a safe, efficacious, and feasible intervention for patients with refractory or recurrent CDI in Hong Kong. Given the increasing disease burden and the lack of effective alternatives in Hong Kong for difficult-to-treat cases of CDI, we recommend that a territory-wide FMT service be established to address increasing demand for this treatment.

Comparison of high-flow nasal cannula versus oxygen face mask for environmental bacterial contamination in critically ill pneumonia patients: a randomized controlled crossover trial

Whereas high-flow nasal cannula use is gaining prevalence, its high gas flow raises concerns about aerosolization of infectious particles and spread of infection. This randomized controlled crossover non-inferiority trial (N = 20) evaluated the degree of environmental contamination by viable bacteria associated with the use of high-flow nasal cannula compared with conventional oxygen mask for critically ill patients with Gram-negative pneumonia. The results show that high-flow nasal cannula use was not associated with increased air or contact surface contamination by either Gram-negative bacteria or total bacteria, suggesting that additional infection control measures are not required.

Virological response to peramivir treatment in adults hospitalised for influenza-associated lower respiratory tract infections

An open-label trial on intravenous peramivir was conducted among adult patients hospitalised for influenza-associated lower respiratory tract complications (LRTCs). Virus culture and quantitative reverse transcription PCR (qRT-PCR) were performed serially until Day 10. Peramivir treatment was associated with viral RNA decline as well as culture and RNA negativity, which occurred at rates comparable with those of oseltamivir: by Day 5, viral load decline -2.5 log10 copies/mL [βinteraction -0.071, standard error (SE) 0.121, 95% confidence interval (CI) -0.309 to 0.167]; culture-negative, 94% (vs. 95%); and RNA-negative, 44% (vs. 36%). Extended treatment of >5 days was required in 69% of cases because of slow clinical resolution and viral clearance in LRTCs. Peramivir was well tolerated. These data are useful for future trial design in this unique population.

High morbidity and mortality in adults hospitalized for respiratory syncytial virus infections

BACKGROUND

Better understanding of complications and outcomes of adults hospitalized with respiratory syncytial virus (RSV) infection is necessary.

METHODS

A retrospective cohort study was conducted on all adults (≥ 18 years) admitted to 3 acute care general hospitals in Hong Kong with virologically confirmed RSV infection during 2009-2011 (N = 607). Adults hospitalized for seasonal influenza during the period were used for comparison (n = 547). Both infections were prospectively diagnosed following a standard protocol. Independent reviews of chest radiographs were performed by radiologists. Main outcome measures were all-cause death, respiratory failure requiring ventilatory support, and hospitalization duration. Cox proportional hazards models were used for analyses.

RESULTS

The mean age of RSV patients was 75 (SD, 16) years; 87% had underlying conditions. Lower respiratory and cardiovascular complications were diagnosed in 71.9% (pneumonia, 42.3%; acute bronchitis, 21.9%; chronic obstructive pulmonary disease/asthma exacerbation, 27.3%) and 14.3% of patients, respectively; 12.5% had bacterial superinfections. Supplemental oxygen and ventilatory support were required in 67.9% and 11.1%, respectively. Crude all-cause mortality was 9.1% and 11.9% within 30 days and 60 days, respectively; mean length of stay of survivors was 12 (SD, 13) days. Advanced age, radiographic pneumonia, requirement for ventilation, bacterial superinfection, and elevated urea level and white blood cell count were independently associated with poorer survival. Systemic corticosteroid use was associated with longer hospitalization and secondary infections. The overall outcomes of survival and length of stay were not significantly different from those in influenza.

CONCLUSIONS

RSV can cause severe lower respiratory complications in older adults, resulting in respiratory failure, prolonged hospitalization, and high mortality similar to seasonal influenza. Corticosteroids did not seem to improve outcomes. The unmet need for antiviral therapy and vaccination against RSV in adults should be promptly addressed.

Respiratory viruses and atypical bacteria triggering severe asthma exacerbation in children

1. Respiratory viruses and atypical bacteria were detected in 51.0% of Hong Kong children with asthma exacerbations, which was significantly higher than the detection rate of 27.3% in children with chronic stable asthma. 2. Co-infections of two or more respiratory pathogens were more commonly found in children with asthma exacerbations (10.7%) than in patients with stable asthma (2.6%). 3. Human rhinovirus infection was a significant risk factor for asthma exacerbations. 4. There was no significant association between the severity of asthma exacerbations and respiratory viral or atypical bacterial infections. 5. Routine use of macrolide antibiotics in the treatment of childhood asthma exacerbations should be discouraged.

Influenza virus load in hospitalised patients

1. Hospitalised patients with severe influenza have persistently high viral loads, for whom a different therapeutic approach may be needed. 2. Active screening of influenza infection should be performed in all high-risk patients hospitalised with febrile respiratory illness. Early diagnosis and treatment to suppress the high viral load may maximise clinical benefit. 3. For late presenting high risk patients with severe symptoms, their viral load may remain high, and initiation of antiviral treatment may still be worthwhile. 4. More stringent infection control measures, including strict droplet precautions and preferably isolation for an extended period of time may be necessary owing to prolonged viral shedding. 5. Randomised, controlled trials are indicated to address timing and dosage of treatment for severe influenza infection.

Relationship between age and prevalence of hepatitis B infection in first-year university students in Hong Kong

PURPOSE

To determine the effect of age on the prevalence of hepatitis B virus (HBV) infection during a routine screening programme of first-year students enrolled in Health Sciences Studies at the Chinese University of Hong Kong from 2001 to 2009.

METHODS

In a retrospective cohort study, data on the hepatitis B surface antigen (HBsAg) status was retrieved from the University Health Service and analysed according to the age of the student at testing and year of birth.

RESULTS

Of the 2,688 students enrolled in the study group, 79 (2.9 %) tested positive for HBsAg. The prevalence increased significantly from 0.9, 2.3, 4.3 to 5.5 % for those tested at age ≤ 18, 19, 20 and ≥ 21 years, respectively (p < 0.001). On logistic regression analysis, taking age ≤ 18 years and year of birth before 1983 (before the availability of HBV vaccination) as the reference group, HBV infection increased progressively with age, with an adjusted odds ratio of 3.36 [95 % confidence interval (CI) 1.01-11.23], 6.04 (95 % CI 1.74-20.98) and 11.61 (95 % CI 3.20-42.13) for age 19, 20 and ≥ 21 years, respectively. There was no significant change in the odds ratio after adjustment for the year of birth before and after introduction of the vaccination programme.

CONCLUSION

Among the university students enrolled in our study, the overall prevalence of HBV infection before and after the introduction of HBV vaccination was lower than the 10 % found in the general population. There was, however, a significant progressive increase with age at testing from ≤ 18 to ≥ 21 years, suggesting a previously overlooked contribution of horizontal transmission to the high prevalence of HBV infection found in our adult population.

Differences in the compliance with hospital infection control practices during the 2009 influenza H1N1 pandemic in three countries

BACKGROUND

In December 2009, the World Health Organization (WHO) issued updated guidelines on the prevention of H1N1 influenza virus in healthcare settings. In 2010, the WHO pandemic influenza alert level was still at phase 6.

AIM

To study the practice of infection control measures during the 2009 influenza H1N1 pandemic among healthcare workers (HCWs) in three countries.

METHODS

A standardized, self-administered anonymous questionnaire survey was conducted in 2010 among doctors, nurses and allied HCWs in 120 hospital-based clinical departments in Hong Kong, Singapore and the UK. Questions were asked on demographics; previous experience and perceived severity of influenza; infection control practices; uptake of seasonal influenza vaccination and H1N1 vaccination. Multiple logistic regression was used to test the independent association with different factors.

FINDINGS

A total of 2100 HCWs in the three countries participated. They reported high compliance (>80%) with infection control procedures regarded as standard for droplet-transmitted infections including wearing and changing gloves, and washing hands before and after patient contact. However, the reported use of masks with indirect or direct patient contact (surgical or N95 as required by their hospital) varied considerably (96.4% and 70.4% for Hong Kong; 82.3% and 87.7% for Singapore; 25.3% and 62.0% for the UK). Reported compliance was associated with job title, number of patient contacts and perceived severity of pandemics. There was no association between the uptake for seasonal or 2009 H1N1 vaccines and compliance.

CONCLUSIONS

Compliance with infection control measures for pandemic influenza appears to vary widely depending on the setting.

Neonatal herpes: what lessons to learn

Vesicular rashes in neonates are challenging in terms of diagnosis and management. Herpes infection is an important diagnostic consideration. We report two illustrative neonatal cases of herpesvirus infections with vesicular rashes. Such babies may be remarkably asymptomatic. A high index of suspicion leading to a prompt diagnosis, timely quarantine measures, and institution of antiviral treatment are pivotal for desirable outcomes.

Human coronavirus NL63 in children: epidemiology, disease spectrum, and genetic diversity

1. Human coronaviruses (HCoVs)were detected in 2.5% of 2982 local children hospitalised for acute respiratory infections in 2005 to 2007. 2. Using the 'pancoronavirus' reverse transcription-polymerase chain reaction assay, detection rates were 0.6% for HCoVNL63,1.2% for HCoV-OC43,0.5% for HCoV-HKU1, and 0.2% for HCoV-229E. Notably, HCoV-NL63 infections were significantly more common among children hospitalised in 2006/2007 (1.2%) than in 2005/2006 (0.3%).3. The peak season for HCoVNL63 infection was autumn(September to October). 4. HCoV-NL63 infection was associated with younger age,croup, febrile convulsion, and acute gastroenteritis. Such disease associations were not found with the other three HCoVs. 5. Most local HCoV-NL63 isolates were closely related to the prototype strain in Netherlands(NL496), but a few were phylogenetically distinct from the major cluster.

Factors associated with length of hospital stay in children with respiratory disease

OBJECTIVES

To explore factors associated with length of stay, and secondarily to explore the potential of enhanced diagnostics to address respiratory disease burden in children.

DESIGN

Prospective study.

SETTING

A university teaching hospital in Hong Kong.

PATIENTS

Data from 475 children with respiratory tract symptoms or fever admitted to Prince of Wales Hospital, Hong Kong from November 2005 to April 2007.

MAIN OUTCOME MEASURES

Aetiological diagnoses based on enhanced diagnostics and their association with clinical information.

RESULTS

Data from 469 subjects showed that major presentations were fever (84%), cough (72%), and runny nose (64%). The median length of stay was longest (3 days) for adenovirus, metapneumovirus and mycoplasma infections, while children with negative aetiological results had a median length of stay of 2 days. Fever duration during admission (P<0.001), the highest recorded temperature during admission (P < 0.001), use of antibiotics during admission (P<0.001), ear pain before admission (P = 0.019), and high white cell counts (P = 0.021) were associated with increased length of stay (univariate analysis). Identifying an aetiological agent did not affect length of stay. Comparison of children with a positive immunofluorescence test result (rapidly available) with those in whom the test was negative though a positive multiplex polymerase chain reaction ensued (result not available to clinicians) also showed no association with length of stay.

CONCLUSION

Although rapid enhanced diagnostics may not have a major influence on length of stay, these data form an integral part of enhanced sentinel surveillance systems.

Monitoring of perceptions, anticipated behavioral, and psychological responses related to H5N1 influenza

BACKGROUND

The aim of this study was to monitor changes in behavioral and emotional responses to human H5N1 in the community over a 28-month period (from November 2005 to February 2008).

METHODS

A total of 3,527 Hong Kong Chinese adults were interviewed by telephone within the framework of six identical cross-sectional surveys carried out during the 28-month study period. Given a hypothetical scenario that two to three new human-to-human H5N1 cases had been reported in Hong Kong, the trends of the respondents in various H5N1-related risk perceptions, anticipated personal psychological responses, and anticipated personal preventive behaviors were investigated.

RESULTS

Over time, a decreased proportion of the respondents (1) felt susceptible to contracting H5N1, (2) expected a large outbreak would eventually occur, (3) believed that the impacts of H5N1 were worse than those of severe acute respiratory syndrome (SARS), and (4) anticipated adopting more types of preventive measures and experiencing mental distress in the case of a small-scale outbreak in Hong Kong (AOR from 0.27 to 0.43, p < 0.001), but the public remained vigilant on public health behaviors, such as hand-washing. The prevalence of misconceptions on the mode of transmission declined, but remained high; perceptions on the fatality of H5N1 remained largely underestimated. The SARS experience and unconfirmed beliefs about the transmission modes were associated with variables on anticipated preventive behaviors and emotional distress.

CONCLUSION

Starting in 2005 through to 2008, respondents perceived a decreasing level of susceptibility, severity, and anticipated stress towards a hypothetical human-to-human H5N1 outbreak, possibly due to the low efficiency of transmission. The public's general preparedness was still relatively good and rational, even though individual preventive behaviors were less common. However, misconceptions were prevalent among the respondents. Based on these results, public education is warranted to rectify these misconceptions.

Outcomes of adults hospitalised with severe influenza

BACKGROUND

The aim of this study was to investigate factors affecting clinical outcomes of adults hospitalised with severe seasonal influenza.

METHODS

A prospective, observational cohort study was conducted over 24 months (2007-2008) in two acute, general hospitals. Consecutive, hospitalised adult patients were recruited and followed once their laboratory diagnosis of influenza A/B was established (based on viral antigen detection and virus isolation from nasopharyngeal aspirates collected per protocol). Outcomes studied included in-hospital death, length of stay and duration of oxygen therapy. Factors affecting outcomes were analysed using multivariate Cox proportional hazards models. Sequencing analysis on the neuraminidase gene was performed for available H1N1 isolates.

RESULTS

754 patients were studied (influenza A, n=539; >75% H3N2). Their mean age was 70+/-18 years; co-morbidities and serious complications were common (61-77%). Supplemental oxygen and ventilatory support was required in 401 (53.2%) and 41 (5.4%) patients, respectively. 39 (5.2%) patients died; pneumonia, respiratory failure and sepsis were the causes. 395 (52%) patients received antiviral (oseltamivir) treatment. Omission of antiviral treatment was associated with delayed presentation or negative antigen detection results. The mortality rate was 4.56 and 7.42 per 1000 patient-days in the treated and untreated patients, respectively; among those with co-morbidities, it was 5.62 and 11.64 per 1000 patient-days, respectively. In multivariate analysis, antiviral use was associated with reduced risk of death (adjusted HR (aHR) 0.27 (95% CI 0.13 to 0.55); p<0.001). Improved survival was observed with treatment started within 4 days from onset. Earlier hospital discharge (aHR 1.28 (95% CI 1.04 to 1.57); p=0.019) and faster discontinuation of oxygen therapy (aHR 1.30 (95% CI 1.01 to 1.69); p=0.043) was associated with early treatment within 2 days. Few (n=15) H1N1 isolates in this cohort had the H275Y mutation.

CONCLUSIONS

Antiviral treatment for severe influenza is associated with reduced mortality and improved clinical outcomes.

Mechanisms of lymphocyte loss in SARS coronavirus infection

1. Human lymphocytes and monocytes are not permissive to productive SARS coronavirus (SARS-CoV) infection in vitro. 2. Challenge of lymphocytes and monocytes with infectious SARS-CoV, inactivated virions, and receptor-binding fragment of spike protein does not trigger apoptosis. 3. Direct infection/interaction between viruses and lymphocytes/monocytes is unlikely to be the cause of lymphopaenia in SARS patients. 4. Lymphopaenia in SARS patients is likely to result from indirect mechanisms secondary to the viral infection.

Influenza-like illness in residential care homes: a study of the incidence, aetiological agents, natural history and health resource utilisation

BACKGROUND

Influenza-like illness (ILI) among elderly people living in residential care homes (RCHEs) is a common cause for hospitalisation. A study was undertaken to examine the incidence, underlying aetiology, natural history and associated healthcare resource utilisation related to ILI in the RCHE population.

METHODS

A prospective study of ILI in four RCHEs in Shatin, Hong Kong was conducted from April 2006 to March 2007. Each RCHE was monitored daily for the occurrence of ILI and followed up until resolution of illness or death. Clinical features were recorded and sputum, nasopharyngeal aspirate, blood and urine specimens were examined for underlying aetiology.

RESULTS

259 episodes of ILI occurred in 194 subjects, with mild peaks in winter and summer, over a sustained level throughout the year. The infectious agent was identified in 61.4% of all episodes, comprising bacterial infection in 53.3% and viral in 46.7%. Multiple infections occurred in 16.2% of subjects. The most frequent organism was Streptococcus pneumoniae, followed by respiratory syncytial virus, Pseudomonas aeruginosa, metapneumovirus and parainfluenza virus types 1 and 3. Clinical features did not vary according to the underlying aetiology, the common presenting features being a decrease in general condition, cognitive and functional deterioration, and withholding of food in addition to fever and respiratory symptoms. Overall, mortality at 1 month/discharge was 9.7%. Infection with methicillin-resistant Staphylococcus aureus, low body mass index and poor function predisposed to mortality. No association was observed between influenza vaccination status and underlying aetiology, clinical features or outcome.

CONCLUSIONS

The clinical presentation of ILI is non-specific and is mainly due to bacterial and viral infections other than influenza in the RCHE population.

Co-circulation of human metapneumovirus and SARS-associated coronavirus during a major nosocomial SARS outbreak in Hong Kong

Background

The clinico-epidemiological significance of human metapneumovirus (hMPV) detected during the SARS outbreak is unknown.

Objectives

To characterize a nosocomial hMPV outbreak during the 2003 SARS epidemic.

Study design and methods

All available nasopharyngeal aspirate (NPA) collected from confirmed patients during the first 8 weeks of the SARS outbreak in 2003 were tested for hMPV by a nested RT-PCR assay targeting the F-gene. Clinico-epidemiological information was used to analyze the relationship of hMPV co-infection to specific risk factors (demographics/symptoms/outcomes; status as health-care workers (HCWs)/patients; history of exposure/contact; ward location). Multivariate logistic regression analysis was performed to determine independent risk factors.

Results

An hMPV outbreak occurred during 6–16 March 2003 (first week of the Hong Kong SARS epidemic). hMPV RNA was detected in 31 of 155 (20%) NPAs from SARS patients. HCW status (OR 2.72, 95% CI 1.11–6.68; p = 0.029) or epidemiological linkage to the SARS outbreak ward (OR 3.59, 95% CI 1.42–9.05; p = 0.007) were independent factors associated with hMPV infection. Symptoms of cough and coryza were more common in co-infected individuals (22.6% vs. 15.9%) but this was not statistically significant. Other clinical manifestations and outcomes were not different in co-infected patients.

Conclusions

A major nosocomial hMPV outbreak involving HCWs occurred during the early SARS epidemic. Patients with dual hMPV and SARS infection were not sicker than those with SARS infection only.

Hypercytokinemia and hyperactivation of phospho-p38 mitogen-activated protein kinase in severe human influenza A virus infection

BACKGROUND

We postulate that hypercytokinemia plays a role in immunopathogenesis of severe human influenza.

METHODS

We prospectively studied 39 consecutive patients who were hospitalized with severe influenza A virus infection. On laboratory confirmation of the diagnosis, paired acute-phase (obtained at hospital admission) and convalescent-phase (obtained >10 days after hospital admission) plasma samples were collected for assay of 11 cytokines and chemokines (interleukin [IL] 1 beta; IL-6; IL-10; IL-12p70; tumor necrosis factor alpha; IL-8; monokine induced by interferon [IFN]-gamma; IFN-inducible protein 10; monocyte chemoattractant protein 1; regulated upon activation, normal T cell-expressed and secreted; and IFN-gamma) using cytometric bead-array analysis and enzyme-linked immunosorbent assay. Simultaneously, virus concentration in the acute-phase nasopharyngeal aspirate was determined using real-time quantitative reverse-transcriptase polymerase chain reaction. Intracellular signaling molecules regulating lymphocyte activation, phospho-p38 mitogen-activated protein kinase and phospho-extracellular signal-regulated protein kinase in CD4+ and CD8+ T lymphocytes were studied in the acute-phase samples using flow cytometric analysis and were compared with results for samples from healthy control subjects.

RESULTS

Statistically significant increases in plasma IL-6 (3.7-fold increase), IL-8 (2.6-fold increase), IFN-induced protein 10 (4.9-fold increase), and monokine induced by IFN-gamma (2.3-fold increase) concentrations were detected during acute illness (P < .01 for all, by Wilcoxon signed-rank test); the highest concentrations were observed on symptom days 3 and 4. Corresponding plasma cytokine and chemokine concentrations and nasopharyngeal viral loads showed statistically significant correlations (rho = 0.41, 0.49, 0.54, and 0.46, respectively; P < or = .01). Phospho-p38 mitogen-activated protein kinase expression in CD4+ lymphocytes was increased, correlating with cytokine concentrations (e.g., for IFN-induced protein 10, rho = 0.78; P < .01); phospho-extracellular signal-regulated protein kinase was suppressed. Advanced age and comorbidity were associated with aberrant IL-6, IL-8, and monokine induced by IFN-gamma responses (P < .05, by Mann-Whitney U test). An elevated IL-6 concentration was independently associated with prolonged hospitalization (hospitalization for >5 days; P = .02), adjusted for age, comorbidity, and virus load.

CONCLUSIONS

Hypercytokinemia (of proinflammatory and T helper 1 cytokines) is detected in severe influenza, correlating with clinical illness and virus concentration. Hyperactivation of phospho-p38 mitogen-activated protein kinase (in T helper cells) is possibly involved. Early viral suppression may attenuate these potentially deleterious cytokine responses.

Features discriminating SARS from other severe viral respiratory tract infections

This study investigated the discriminatory features of severe acute respiratory syndrome (SARS) and severe non-SARS community-acquired viral respiratory infection (requiring hospitalization) in an emergency department in Hong Kong. In a case-control study, clinical, laboratory and radiological data from 322 patients with laboratory-confirmed SARS from the 2003 SARS outbreak were compared with the data of 253 non-SARS adult patients with confirmed viral respiratory tract infection from 2004 in order to identify discriminatory features. Among the non-SARS patients, 235 (93%) were diagnosed as having influenza infections (primarily H3N2 subtype) and 77 (30%) had radiological evidence of pneumonia. In the early phase of the illness and after adjusting for baseline characteristics, SARS patients were less likely to have lower respiratory symptoms (e.g. sputum production, shortness of breath, chest pain) and more likely to have myalgia (p < 0.001). SARS patients had lower mean leukocyte and neutrophil counts (p < 0.0001) and more commonly had “ground-glass” radiological changes with no pleural effusion. Despite having a younger average age, SARS patients had a more aggressive respiratory course requiring admission to the ICU and a higher mortality rate. The area under the receiver operator characteristic curve for predicting SARS when all variables were considered was 0.983. Using a cutoff score of >99, the sensitivity was 89.1% (95%CI 82.0–94.0) and the specificity was 98.0% (95%CI 95.4–99.3). The area under the receiver operator characteristic curve for predicting SARS when all variables except radiological change were considered was 0.933. Using a cutoff score of >8, the sensitivity was 80.7% (95%CI 72.4–87.3) and the specificity was 94.5% (95%CI 90.9–96.9). Certain clinical manifestations and laboratory changes may help to distinguish SARS from other influenza-like illnesses. Scoring systems may help identify patients who should receive more specific tests for influenza or SARS.

Patients with malignant or pre-malignant cervical lesion have increased risk of becoming hepatitis B carrier

Human Papillomavirus (HPV) and Hepatitis B virus (HBV) are known aetiology of cervical and hepatocellular carcinoma, respectively. Both diseases share a similar clinical course, that is, the vast majority of those infected by these two viruses can eradicate the viruses spontaneously. A small sub-group who fails to clear the virus becomes chronic carrier and can progress to carcinoma many years later. We postulated that patients with pre-malignant or malignant cervical lesion are at increased risk of becoming chronic HBV carrier if infected, which may be attributed to inherent immunological deficiency against viral infection. We tested HBV carrier status from 288 patients with cervical carcinoma, 242 patients with high grade cervical intra-epithelial neoplasia (CIN) and 311 women with neither of the above conditions as control subjects. The HBV carrier rate in the Cancer Group, CIN Group and Control Group was 21.4%, 24.1% and 10.6%. The carrier rate was significantly higher in both the Cancer Group (p<0.01) and the CIN Group (p<0.01), compared to the Control Group. Our study suggests that a common immunological mechanism is involved in eradication of HBV and HPV infections and inherent immuno-deficiency might lead to an association of HBV carrier status with cervical carcinoma. Further studies are needed to confirm our findings and delineate the mechanism involved.

Antiviral property and mechanisms of a sulphated polysaccharide from the brown alga Sargassum patens against Herpes simplex virus type 1

A sulphated polysaccharide (SP-2a) from the brown alga Sargassum patens (Kütz.) Agardh (Sargassaceae) was found to significantly inhibit the in vitro replication of both the acyclovir (ACV)-sensitive and -resistant strains of Herpes simplex virus type 1 (HSV-1), in dose-dependent manners, with 50% inhibitions occurring with 1.5-5.3 microg/ml of the polysaccharide. SP-2a exhibited extracellular virucidal activity only against the ACV-sensitive strains, but not the resistant strain, at the concentration of 100 microg/ml. The strongest antiviral activities against the different strains of HSV-1 were observed when this polysaccharide was present during and after adsorption of the virus to host cells. The inhibitory effect of SP-2a on virus adsorption occurred dose-dependently in all the HSV-1 strains tested, and the adsorption of the ACV-resistant DM2.1 strain was reduced by 81.9% (relative to control) with 4 microg/ml of the polysaccharide. This study clearly demonstrated that the antiviral mode of action of SP-2a is mediated mainly by inhibiting virus attachment to host cells, and this sulphated polysaccharide might have different modes of action against the ACV-sensitive and -resistant strains of HSV-1.

Extremely low exposure of a community to severe acute respiratory syndrome coronavirus: false seropositivity due to use of bacterially derived antigens

Estimates of seropositivity to a new infectious agent in a community are useful to public health. For severe acute respiratory syndrome (SARS), the figures are conflicting. Herein, we screened 12,000 people in a community stricken by SARS 10 months previously and found 53 individuals (0.44%) who had immunoglobulin G antibodies to the SARS coronavirus (SARS-CoV) nucleocapsid (N) produced in bacteria. However, only seven of these (group 1) had sera which also reacted with the native N antigen expressed in SARS-CoV-infected Vero cells, N-transfected 293T cells, and tissues of infected SARS patients. Of these, six individuals had had SARS previously. The remaining person, as well as the 46 other individuals (group 2), were healthy and had no history of SARS. Group 1 antibodies recognized epitopes located slightly differently in N from those of group 2 antibodies, and a mouse hybridoma antibody resembling the former type was generated. Unusually, group 2 antibodies appeared to recognize cross-reactive bacterial epitopes that presumably were posttranslationally modified in eukaryotes and hence were probably not induced by SARS-CoV or related coronaviruses but rather by bacteria. The N antigen is thus highly unique. The extremely low rate (0.008%) of asymptomatic SARS infection found attests to the high virulence of the SARS-CoV virus.

Factors involved in the aerosol transmission of infection and control of ventilation in healthcare premises

The epidemics of severe acute respiratory syndrome (SARS) in 2003 highlighted both short- and long-range transmission routes, i.e. between infected patients and healthcare workers, and between distant locations. With other infections such as tuberculosis, measles and chickenpox, the concept of aerosol transmission is so well accepted that isolation of such patients is the norm. With current concerns about a possible approaching influenza pandemic, the control of transmission via infectious air has become more important. Therefore, the aim of this review is to describe the factors involved in: (1) the generation of an infectious aerosol, (2) the transmission of infectious droplets or droplet nuclei from this aerosol, and (3) the potential for inhalation of such droplets or droplet nuclei by a susceptible host. On this basis, recommendations are made to improve the control of aerosol-transmitted infections in hospitals as well as in the design and construction of future isolation facilities.

Precautions in ophthalmic practice in a hospital with a major acute SARS outbreak: an experience from Hong Kong

Many new infectious diseases in humans have been derived from animal sources in the past 20 years. Some are highly contagious and fatal. Vaccination may not be available and antiviral drugs are not effective enough. Infectious control is important in clinical medicine and in Ophthalmology. Severe acute respiratory syndrome (SARS), as an example, is a highly contagious respiratory disease that has recently been reported in Asia, North America, and Europe. Within a matter of weeks, the outbreak has evolved to become a global health threat and more than 30 countries have been afflicted with a novel Coronavirus strain (SARS-CoV) that is the aetiologic agent of SARS. The primary route of transmission of SARS appears involving close person-to-person contact through droplets. Ophthalmologists may be particularly susceptible to the infection as routine ophthalmic examinations like direct ophthalmoscopy and slit-lamp examination are usually performed in a setting that has close doctor-patient contact. Being the Ophthalmology Department of the only hospital in the world that has just gone through the largest outbreak of SARS, we would like to share our strategy, measures, and experiences of preventing contracting or spreading of SARS infection as an infection control model. SARS is one of the many viruses against which personnel will need protecting in an ophthalmic setting. The experiences attained and the measures established might also apply to other infectious conditions spreading by droplets such as the avian influenza with H5N1.

The detection of human herpesvirus-8 DNA in plasma and peripheral blood mononuclear cells in adult patients with pityriasis rosea by polymerase chain reaction

BACKGROUND

Herpesvirus-like particles have been reported to be detectable by electron microscopy in lesional biopsy of patients with pityriasis rosea (PR). We report a study investigating the association of PR with human herpesvirus-8 (HHV-8) infection.

METHODS

Our setting is a teaching clinic affiliated to a university. We recruited eight patients aged 28-47 years (mean: 34.5 years) diagnosed with PR during a one-year period. We collected acute blood specimens at presentation and convalescent blood specimens three to four weeks later. We also collected skin scrapings from the herald patch where present and from truncal secondary lesions.

RESULTS

We detected HHV-8 DNA by a nested PCR (polymerase chain reaction) targeting, respectively, a 233-bp and a 160-bp fragment of ORF 26. PCR for HHV-8 DNA was negative in the peripheral blood mononuclear cells and plasma of acute and convalescent specimens of all patients, and negative in all skin scrapings. We detected anti-HHV-8 IgG and IgM antibodies by the indirect immunofluorescence. Four patients had IgG antibodies against HHV-8, but with no significant rise of titre. None were positive for anti-HHV-8 IgM antibody.

CONCLUSION

We conclude that PR is not associated with HHV-8 infection.