Investigation of a COVID-19 cluster involving vertical transmission in a residential building, Taiwan, 2021

We investigated a COVID-19 cluster involved seven case-patients lived in a high-rise building in September 2021. We used a simplified tracer-gas experiment and virus sequencing to establish the link between case-patients. Vertical transmission among vertically aligned apartments on different floors in a building was the most likely route of transmission.

Gender differences in risk exposures for acute hepatitis C infection in Taiwan: a nationwide case-control study

BACKGROUND

In Taiwan, medical providers are required to report all acute hepatitis C (AHC) patients to National Notifiable Disease Surveillance System (NNDSS). Identifying factors associated with AHC may inform the strategies to prevent the spread of hepatitis C virus (HCV). We used the national surveillance data to assess gender difference in risk factors associated with AHC in Taiwan and propose control measures in at-risk groups.

METHODS

We conducted a nationwide case-control study using data from NNDSS and AHC case investigation questionnaires, for the period of March 6, 2014-December 31, 2016. Cases were AHC confirmed in NNDSS; controls were reported AHC with negative HCV nucleic acid test and negative serum anti-HCV antibody. We used bivariate analysis to identify characteristics and risk exposures for AHC and conducted gender stratified analyses.

RESULTS

We identified 602 AHC cases (66.9% males, median age 48 years) and 90 controls. Older age, male gender (OR: 1.85, 95% CI: 1.18-2.90), history of viral hepatitis (OR: 7.93, 95% CI:1.91-32.88), history of sexually transmitted infections (OR: 21.02, 95% CI: 2.90-152.43), and having healthcare-associated risk exposures (OR: 2.02, 95% CI: 1.25-3.25) were associated with AHC. Stratified analyses showed receiving intravenous infusion, history of hepatitis B, syphilis, and human immunodeficiency virus infection were risk factors for male AHC; receiving hemodialysis was risk factor for females.

CONCLUSIONS

Our study demonstrates risk factors for AHC in Taiwan with gender difference. Proper infection control practices in healthcare settings and interventions targeting male patients with HIV and other STIs, remain crucial to prevent individuals from AHC.

Probable Aerosol Transmission of SARS-CoV-2 through Floors and Walls of Quarantine Hotel, Taiwan, 2021

We investigated a cluster of SARS-CoV-2 infections in a quarantine hotel in Taiwan in December 2021. The cluster involved 3 case patients who lived in nonadjacent rooms on different floors. They had no direct contact during their stay. By direct exploration of the space above the room ceilings, we found residual tunnels, wall defects, and truncated pipes between their rooms. We conducted a simplified tracer-gas experiment to assess the interconnection between rooms. Aerosol transmission through structural defects in floors and walls in this poorly ventilated hotel was the most likely route of virus transmission. This event demonstrates the high transmissibility of Omicron variants, even across rooms and floors, through structural defects. Our findings emphasize the importance of ventilation and integrity of building structure in quarantine facilities.

Inhaled Zanamivir versus Oral Oseltamivir to Prevent Influenza-related Hospitalization or Death: a Nationwide Population-based Quasi-experimental Study

BACKGROUND

Individual patient data meta-analyses of randomized controlled trials show that early oseltamivir treatment for influenza cut risk of pneumonia and hospitalization by 44% and 63%, respectively. However, data are lacking for inhaled zanamivir on its effectiveness to prevent hospitalization and death.

METHODS

This nationwide, population-based cohort study included all outpatients treated with inhaled zanamivir or oral oseltamivir, within 48 hours after a clinical diagnosis of influenza, before and after the rollout of inhaled zanamivir as the first-line antiviral in Taiwan. The main outcome is influenza-related hospitalization or death within 14 days, ascertained using Taiwan national health insurance database and national death registry, respectively. Those developed the outcome within 2 days were excluded from analyses. Propensity score stratification was used to control confounding from covariates.

RESULTS

A total of 865,032 eligible influenza outpatients were included in the analysis. The risk of developing the main outcome (adjusted hazard ratio [aHR]: 1.01, 95% confidence interval [CI]: 0.96 to 1.06) did not differ between inhaled zanamivir group (n = 595,897, 68.9%, the reference) and oral oseltamivir group (n = 269,135, 31.1%). Prespecified analysis on high-risk subgroups further showed that inhaled zanamivir is not inferior to oral oseltamivir in either >65 years elderly patients (aHR: 1.14, 95% CI: 1.05 to 1.25) or patients with chronic lung diseases (aHR: 1.23, 95% CI: 1.08 to 1.41).

CONCLUSION

Inhaled zanamivir is not inferior to oral oseltamivir as outpatient treatment to prevent influenza-related hospitalization or death, for patients whose conditions do not require hospitalization within 2 days.

Hepatitis C outbreak in a respiratory care ward associated with frequent injections: Taiwan, 2017

BACKGROUND

Healthcare-associated outbreaks of hepatitis C virus (HCV) infection pose serious risks of harm to patients. During May-July 2017, the Taiwan Centers for Disease Control were notified of four patients with acute HCV infection in a respiratory care ward (RCW). To prevent further infection, an investigation was conducted to identify the transmission route and risk factors for infection.

METHODS

We tested patients and staff members of the RCW for HCV, reviewed medical records, observed infection control practices on-site, and undertook a case-control study. We defined cases as individuals who had stayed in the RCW 2 weeks to 6 months prior to the laboratory diagnosis date of the first case and were infected with HCV after admission. Patients who were hospitalized during the same period but whose HCV tests were negative were selected as controls. We used Mann-Whitney U test to compare the frequency of injections among cases and controls.

RESULTS

Of 19 staff and 29 patients, we identified four case-patients and one patient with chronic hepatitis C whose HCV RNA similarity was >98%. Compared to the 12 controls, the case-patients received more injections per day (4.4 vs. 0.1; p = 0.01). The RCW lacked designated areas and standardized workflows for injection preparation. Disinfection of the environment and equipment was inadequate, which could possibly lead to blood contamination of the environment and parenteral medications.

CONCLUSION

HCV infection was associated with frequent injections and infection control lapses. Healthcare workers should follow safe injection practices and reduce injection frequency to prevent HCV transmission.

Correlation between Negative Rapid Influenza Diagnostic Test and Severe Disease in Hospitalized Adults with Laboratory-Confirmed Influenza Virus Infection

False-negative rapid influenza diagnostic test (RIDT) results could mislead physicians to exclude an influenza diagnosis. We sought to evaluate the association between negative RIDT and intensive care unit (ICU) admission. We reviewed data from hospitalized adults with laboratory-confirmed influenza virus infections in a tertiary referral hospital in Taiwan from July 2009 to February 2011. The diagnosis was documented by real-time PCR or virus culture. Of 134 hospitalized adults infected with influenza virus, 38 (28%) were admitted to the ICU. Compared with RIDT-positive patients, the percentage of ICU admission was significantly higher among RIDT-negative patients (46% versus 13%, P < 0.001). The RIDT-negative patients had higher percentages of lower respiratory symptoms and more chest radiograph infiltrates. The time interval between the RIDT and antiviral treatment was longer in RIDT-negative than RIDT-positive patients (1.94 days versus 0.03 days, P < 0.001). Among patients presenting with mild illness, only a negative RIDT and delayed antiviral treatment were associated with ICU admission after adjusting for potential confounding factors. To conclude, patients with a negative RIDT were more likely to have severe disease and a delay in initiating antiviral treatment. Our findings should help improve treatment outcomes of hospitalized patients with influenza infection.

Measles Outbreak at a Privately Operated Detention Facility: Arizona, 2016

BACKGROUND

We describe a measles outbreak and control measures implemented at a privately operated detention facility housing US Immigration and Customs Enforcement detainees in 2016.

METHODS

Case-patients reported fever and rash and were either laboratory-confirmed or had an epidemiological link to a laboratory-confirmed case-patient. Immunoglobulin G (IgG) avidity and plaque reduction neutralization tests distinguished between primary acute and reinfection case-patients. Measles-specific IgG was measured to assess detainee immunity levels. We compared attack rates (ARs) among detainees and staff, between IgG-negative and IgG-positive detainees, and by detainee housing units and sexes.

RESULTS

We identified 32 measles case-patients (23 detainees, 9 staff); rash onsets were during 6 May-26 June 2016. High IgG avidity and neutralizing-antibody titers >40000 to measles (indicating reinfection) were identified in 18 (95%) and 15 (84%) of 19 tested case-patients, respectively. Among 205 unit A detainees tested for presumptive immunity, 186 (91%) had detectable IgG. Overall, the AR was 1.65%. ARs were significantly higher among detainees in unit A (7.05%) compared with units B-F (0.59%), and among male (2.33%) compared with female detainees (0.38%); however, ARs were not significantly different between detainees and staff or between IgG-negative and IgG-positive detainees. Control measures included the vaccination of 1424 of 1425 detainees and 190 of 510 staff, immunity verification for 445 staff, case-patient isolation, and quarantine of affected units.

CONCLUSIONS

Although ARs were low, measles outbreaks can occur in intense-exposure settings, despite a high population immunity, underscoring the importance of high vaccination coverage and containment in limiting measles transmission.

Case Investigations of Infectious Diseases Occurring in Workplaces, United States, 2006-2015

Workers in specific settings and activities are at increased risk for certain infectious diseases. When an infectious disease case occurs in a worker, investigators need to understand the mechanisms of disease propagation in the workplace. Few publications have explored these factors in the United States; a literature search yielded 66 investigations of infectious disease occurring in US workplaces during 2006–2015. Reported cases appear to be concentrated in specific industries and occupations, especially the healthcare industry, laboratory workers, animal workers, and public service workers. A hierarchy-of-controls approach can help determine how to implement effective preventive measures in workplaces. Consideration of occupational risk factors and control of occupational exposures will help prevent disease transmission in the workplace and protect workers’ health.

Comparative epidemiology of influenza B by lineage in intensive care unit-admitted patients with complications: A nationwide study in Taiwan, 2013-2017

BACKGROUND

We describe the relative proportions and epidemiological features of influenza B/Victoria and B/Yamagata, using data from nationwide surveillance systems.

METHODS

We collected respiratory samples from outpatients with influenza-like illness (ILI) and intensive care unit (ICU)-admitted patients with complications (pulmonary or neurological complications, myocarditis/pericarditis or invasive bacterial infection) for virus isolation and lineage typing. Demographics, epidemiological features, and vaccination history from ICU-admitted patients with complications were analyzed.

RESULTS

From July 2013-June 2017, 21% of 11517 influenza isolates were influenza B. B/Victoria was the predominant circulating strain in 2013-2014, accounted for 56% of all influenza B positive samples and B/Yamagata was predominant in 2014-2017 (82%, 69%, and 85%, respectively). Among all typed viruses, the proportion of B/Yamagata was higher among specimens from ICU-admitted patients with complications (77%, 154/199) than from ILI outpatients (66%, 276/418, p<0.005). Compared to B/Victoria, B/Yamagata infected ICU-admitted patients with complications were older, median age (71 vs. 59 years, p<0.05), had longer durations of hospitalization (15 vs. 7.5 days, p<0.05) and ICU stays (8.5 vs. 5.5 days, p<0.05).

CONCLUSIONS

Two lineages of influenza B viruses co-circulate annually in Taiwan. Among ICU-admitted patients with complications, B/Yamagata causes more severe illness than B/Victoria.

Occupational coccidioidomycosis surveillance and recent outbreaks in California

Workers in Coccidioides-endemic areas performing soil-disturbing work or exposed to windy and dusty conditions are at increased risk for coccidioidomycosis. Four occupational coccidioidomycosis outbreaks from 2007 to 2014 in California are described, involving construction workers in a number of excavation projects and an outdoor filming event involving cast and crew. These outbreaks highlight the importance of identifying industries and occupations at high risk for coccidioidomycosis, conducting targeted occupational health surveillance to assess the burden of illness, developing and implementing prevention strategies, and setting research priorities.

Seasonal influenza prevention and control in Taiwan-Strategies revisited

Influenza remains a serious public health threat in Taiwan. During 2017-18, Taiwan experienced two seasonal influenza epidemics caused by A/H3N2 and B, respectively. In addition to national influenza vaccination campaign, Taiwan Centers for Diseases Control and Infectious Disease Control Advisory Committee has multi-faceted strategies for seasonal influenza prevention and control to mitigate the risk of disease transmission among vulnerable groups and decrease influenza-related morbidity and mortality. In this article, we reviewed the key elements of the prevention and control strategies-enhanced influenza surveillance, antiviral drugs stockpile and management, critical care and medical resources reallocation, public risk communication and infection control measures. Given the complexity and challenging nature of controlling seasonal influenza epidemics, collaboration between health professionals is crucial to optimize the health of Taiwanese people.

Influenza A(H3N2) virus variants and patient characteristics during a summer influenza epidemic in Taiwan, 2017

We report a summer influenza epidemic caused by co-circulation of multiple influenza A(H3N2) variants in clade 3C.2a. Compared with other clades, a putative clade 3C.2a.3a was more commonly isolated from severely ill patients; 3C.2a.4 was more commonly isolated in outbreak cases. Time from vaccination to illness onset was significantly shorter in severely ill patients infected with clade 3C.2a.3; characteristics and outcomes of patients infected with different clades were similar. No resistance to antiviral medications was found.

Oseltamivir use and outcomes during the 2009 influenza A H1N1 pandemic in Taiwan

Background

The Taiwan CDC provided free oseltamivir to all patients with influenza infections confirmed by rapid testing or who had clinical warning symptoms during the 2009 H1N1 influenza pandemic in Taiwan. However, oseltamivir utilization patterns, cost, and outcomes among oseltamivir-treated patients remained unclear.

Method

A population-level, observational cohort study was conducted using the Taiwan National Health Insurance Database from January to December 2009 to describe the use of oseltamivir.

Result

Prescription trend over weeks increased after a change in government policy and responded to the influenza virus activity. The overall prescription rate was 22.33 per 1000 persons, with the highest prescription rate of 116.5 for those aged 7–12 years, followed by 69.0 for those aged 13–18 years, while the lowest rate was 1.7 for those aged ≥ 65 years. As influenza virus activity increased, the number of prescriptions for those aged ≤18 years rose significantly, whereas no substantial change was observed for those aged ≥65 years. There were also regional variations in terms of oseltamivir utilization and influenza complication rates.

Conclusions

Oseltamivir was widely used in the 2009 H1N1 influenza pandemic in Taiwan, particularly in those aged 7–18 years. The number of prescriptions for oseltamivir increased with a change in government policy and with increasing cases of pandemic influenza. Further study is needed to examine whether there is an over- or under-use of anti-influenza drugs in different age groups or regions and to examine the current policy of public use of anti-influenza drugs to reduce influenza-associated morbidity and mortality.

Predictors and outcomes of respiratory failure among hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan

OBJECTIVES

The worldwide outbreak of a pandemic influenza A (H1N1) virus began in April 2009. We characterized the clinical features of the hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan and elucidated the risk of those patients for developing respiratory failure.

METHODS

Severe complicated influenza infection is a notifiable disease in Taiwan and the hospitalized pneumonia patients with 2009 H1N1 influenza were reported accordingly. We reviewed the medical records of the eligible cases by September 8, 2009; development of respiratory failure was the primary endpoint.

RESULTS

Of the 96 patients we studied, 22 (23%) developed respiratory failure. Among those, 10 (45%) died and all of the non-respiratory failure patients survived. Age distribution, presence of dyspnea, lymphopenia, leukopenia, PaO(2)/FiO(2) ratio, PaCO(2), SOFA score, infiltration on chest x-ray at admission were different between two groups by univariate analysis. The clinical course was also different, with longer duration from onset of symptoms to use of oseltamivir, longer hospital stay, and more complications during hospitalization in patients with respiratory failure. A multivariate logistic regression showed an association between development of respiratory failure and SOFA score > or = 4 at admission, initial lymphocyte count < or = 800/microL, and the duration from symptom onset to initiation of oseltamivir > 48 h.

CONCLUSIONS

Respiratory failure in patients with 2009 H1N1 influenza leads to poor outcomes, including complications and death. Clinicians could apply the three predictors at admission to identify the high-risk pneumonic patients for developing respiratory failure. Further study is needed to validate the findings of this study in other settings.

The role of multiple segment osteotomies in orthognathic surgery

Multiple segment orthognathic (MSO) surgery is an effective approach to deal with a wide range of dento-facial deformities that have occlusal problems. The indications for MSO surgery were patients with dentofacial deformities and malocclusion requiring stable correction within a short overall treatment period. From 1991 to 1998, 107 patients had MSO orthognathic procedures done at Chang Gung Memorial Hospital for maxillary protrusion/deformity (34 cases), maxillary protrusion and mandibular prognathism (69 cases), and non-cleft maxillary retrusion (4 cases). Follow up period ranged from 6 months to 7 years and results showed stability in movements with only 3 complications. The average overall treatment time was approximately 15 months. Our experience with 107 consecutive patients have shown the results of MSO surgery to be good and the procedure safe with no tooth or segment loss.

Combining single- and double-tooth osteotomies with traditional orthognathic surgery

Combining large-segment orthognathic surgery and unitooth or small-segment surgery is an effective approach to deal with a wide range of dentofacial deformities that have minor to severe occlusal problems. The indications for combining single- or double-tooth osteotomies with traditional orthognathic surgery were patients with dentofacial deformities and malocclusion requiring stable correction within a short overall treatment period. From 1991 to 1998, a total of 36 patients underwent combination single- or double-tooth-segment osteotomy with traditional orthognathic procedures performed at Chang Gung Memorial Hospital. The indications for surgery were maxillary protrusion (N = 5), bimaxillary protrusion (N = 19), mandibular prognathism with maxillary protrusion (N = 11), and noncleft maxillary retrusion (N = 1). The types of osteotomies performed were the Le Fort I, the anterior segmental osteotomies of the maxilla or the mandible, the palatal split, and the posterior segment in combination with single-tooth or double-tooth segments. Follow-up ranged from 12 months to 6 years and showed stability in the movements with no complications. There was no loss of any "osteotomized" segment. The average overall treatment time was approximately 18 months--5 months preoperative and 13 months postoperative orthodontic treatment. This was at least 6 months shorter in duration compared with traditional orthognathic surgery. Combining traditional orthognathic surgery with single- or double-tooth segments allows us to treat complex dentofacial deformities in the vertical, transverse, and sagittal dimensions with differential repositioning of all segments, either major or minor, simultaneously. The authors' experience with 36 consecutive patients evidence good results and demonstrate the procedure to be safe with minimal complications.

Localized periodontitis induced by rubber bands. Report of two cases

Two cases of severe localized periodontal destruction caused by rubber bands migrating toward the apices subgingivally are reported. In both cases the patients received periodontal treatment followed by orthodontic treatment and the affected teeth were maintained for two years without extraction. The inappropriate use of rubber bands may cause severe periodontal destruction or even lead to tooth mortality. The use of retentive hooks on orthodontic bands and twisted wire ligatures, as well as close professional supervision, are highly recommended to avoid this hazardous situation.