Population-Based Evaluation of Vaccine Effectiveness against SARS-CoV-2 Infection, Severe Illness, and Death, Taiwan.

Taiwan provided several COVID-19 vaccine platforms: mRNA (BNT162b2, mRNA-1273), adenoviral vector-based (AZD1222), and protein subunit (MVC-COV1901). After Taiwan shifted from its zero-COVID strategy in April 2022, population-based evaluation of vaccine effectiveness (VE) became possible. We conducted an observational cohort study of 21,416,151 persons to examine VE against SARS-CoV-2 infection, moderate and severe illness, and death during March 22, 2021-September 30, 2022. After adjusting for age and sex, we found that persons who completed 3 vaccine doses (2 primary, 1 booster) or received MVC-COV1901 as the primary series had the lowest hospitalization incidence (0.04-0.20 cases/100,000 person-days). We also found 95.8% VE against hospitalization for 3 doses of BNT162b2, 91.0% for MVC-COV1901, 81.8% for mRNA-1273, and 65.7% for AZD1222, which had the lowest overall VE. Our findings indicated that protein subunit vaccines provide similar protection against SARS-CoV-2---associated hospitalization as mRNA vaccines and can inform mix-and-match vaccine selection in other countries.

Risk factors and mortality of SARS-CoV-2 reinfection during the Omicron era in Taiwan: A nationwide population-based cohort study.

BACKGROUND: Prior to 2022, Taiwan had effectively contained the domestic COVID-19 epidemic. However, during 2022, the country encountered multiple large outbreaks of COVID-19, with patients experiencing their first or second infection (reinfection) were both predominantly caused by the Omicron variant. Data are lacking on the risk factors and mortality of COVID-19 reinfection in Omicron era. METHODS: In this retrospective population-based cohort study, we recruited COVID-19 patients with their first episode confirmed between April 1, 2022 and June 11, 2022. A reinfection patient was defined as an individual who infected again by SARS-CoV-2 with an interval of more than 90 days. Demographic characteristics, severity of underlying diseases, and vaccination status were adjusted to identify risk factors for reinfection and to further evaluate the hazard of all-cause mortality within 30 days between reinfection and non-reinfection patients. RESULTS: There were 28,588 reinfection patients matched with 142,940 non-reinfection patients included in this study. We found that being female, younger in age, having more severe underlying diseases, and not being fully vaccinated against COVID-19 were risk factors for reinfection. After adjusting for confounding factors, reinfection patients were at a significantly higher risk of all-cause mortality within 30 days (aHR = 4.29, 95% CI: 3.00-6.12, p < 0.001) comparing with non-reinfection patients. CONCLUSION: During the SARS-CoV-2 Omicron era, reinfection patients were observed to have an increased risk of all-cause mortality. To reduce the disease burden and minimize the risk of reinfection, it is crucial for vulnerable patients to receive full vaccination and adhere to recommended precautions.

Epidemiological characteristics of the three waves of COVID-19 epidemic in Taiwan during April 2022 to March 2023.

BACKGROUND: Taiwan experienced a relatively low incidence of COVID-19 before 2022. However, from April 2022 to March 2023, the country was struck by a nationwide outbreak that occurred in three waves. Despite the considerable magnitude of the epidemic, the epidemiological characteristics of this outbreak have yet to be clearly understood. METHODS: This was a nationwide, population-based, retrospective cohort study. We recruited patients who had been confirmed as domestically-acquired COVID-19 patients from April 17, 2022, to March 19, 2023. The three epidemic waves were analyzed in terms of numbers of cases, cumulative incidence, numbers of COVID-19-related deaths, mortality, gender, age, residence, SARS-CoV-2 variant sub-lineages, and reinfection status. RESULTS: The numbers of COVID-19 patients (cumulative incidence per million population) were 4,819,625 (207,165.3) in the first wave, 3,587,558 (154,206.5) in the second wave, and 1,746,698 (75,079.5) in the third wave, showing a progressive decline. The numbers of COVID-19-related deaths and mortalities also decreased throughout the three waves. The coverage of vaccination was observed to increase over time. CONCLUSION: During the three waves of COVID-19 epidemic, the numbers of cases and deaths gradually declined, while the vaccine coverage increased. It may be appropriate to consider easing restrictions and returning to normality. However, continued monitoring of the epidemiological situation and tracking the emergence of new variants are crucial to prevent the possibility of another epidemic.

The secular trend of enterovirus A71 after the implementation of preventive measures in Taiwan.

BACKGROUND: Enterovirus A71 (EV A71) is one of the most important enteroviruses related to morbidity and mortality in children worldwide. This study aimed to analyse the secular trend of EV A71 in Taiwan from 1998 to 2020 and to evaluate the effectiveness of infection control measures. METHODS: We collected the epidemiological data of EV A71 from disease surveillance systems in Taiwan. We analysed the association between the secular trend of EV A71 and preventive measures such as hand washing, case isolation, and suspension of classes. RESULTS: The incidence of enterovirus infections with severe complications (EVSC) decreased from 16.25 per 100,000 children under six in 1998 to less than 9.73 per 100,000 children under six after 2012 (P = 0.0022). The mortality rate also decreased significantly, from 3.52 per 100,000 children under six in 1998 to 0 per 100,000 children under six in 2020 (P < 0.0001). The numbers of EVSC and fatalities were significantly higher in the years when EV A71 accounted for more than 10% of the annual predominant serotypes (p < 0.05). After the implementation of many non-pharmaceutical interventions in 2012, the incidence of EVSC and mortality rate decreased significantly (p < 0.001). CONCLUSIONS: After implementing active enterovirus surveillance and preventive measures, we found that the incidence of EVSC and fatalities due to EV A71 in Taiwan decreased significantly from 1998 to 2020. Continuous surveillance and strengthened infection control policies are still needed in the future.

An outbreak of SARS-CoV-2 infections among people living with HIV and its successful containment-Taiwan, May to August 2021.

In Taiwan, 14,308 locally acquired COVID-19 cases among customers and employees in Sexy Tea shops were the first cases from May 9-August 28, 2021 (weeks 19-34). Nine weeks after the community spread of COVID-19 began, the proportion of people living with HIV (PLHIV) among the COVID-19 patients peaked at 35.7%, affecting 192 HIV patients, while the prevalence of HIV infection was 0.15%. In addition to a nationwide Level 3 epidemic alert, the Taiwan Centers for Disease Control (Taiwan CDC) launched four strategies to contain this outbreak among PLHIV in this prevaccine era, including improving the quality of contact tracing, delivering health information via peer navigators, expanding SARS-CoV-2 screening and encouraging vaccination, and addressing hesitancy. The outbreak of COVID-19 related to Alpha strain among PLHIV in 2021 ceased four weeks after peaking and lasted eight weeks.

Fast-Response, Highly Air-Stable, and Water-Resistant Organic Photodetectors Based on a Single-Crystal Pt Complex.

Organic semiconductors demonstrate several advantages over conventional inorganic materials for novel electronic and optoelectronic applications, including molecularly tunable properties, flexibility, low-cost, and facile device integration. However, before organic semiconductors can be used for the next-generation devices, such as ultrafast photodetectors (PDs), it is necessary to develop new materials that feature both high mobility and ambient stability. Toward this goal, a highly stable PD based on the organic single crystal [PtBr2 (5,5'-bis(CF3 CH2 OCH2 )-2,2'-bpy)] (or "Pt complex (1o)") is demonstrated as the active semiconductor channel-a material that features a lamellar molecular structure and high-quality, intraligand charge transfer. Benefitting from its unique crystal structure, the Pt-complex (1o) device exhibits a field-effect mobility of ≈0.45 cm2 V-1 s-1 without loss of significant performance under ambient conditions even after 40 days without encapsulation, as well as immersion in distilled water for a period of 24 h. Furthermore, the device features a maximum photoresponsivity of 1 × 103 A W-1 , a detectivity of 1.1 × 1012 cm Hz1/2 W-1 , and a record fast response/recovery time of 80/90 µs, which has never been previously achieved in other organic PDs. These findings strongly support and promote the use of the single-crystal Pt complex (1o) in next-generation organic optoelectronic devices.

Public Health Responses to Reemergence of Animal Rabies, Taiwan, July 16-December 28, 2013.

Taiwan had been free of indigenous human and animal rabies case since canine rabies was eliminated in 1961. In July 2013, rabies was confirmed among three wild ferret-badgers, prompting public health response to prevent human rabies cases. This descriptive study reports the immediate response to the reemergence of rabies in Taiwan. Response included enhanced surveillance for human rabies cases by testing stored cerebrospinal fluids (CSF) from patients with encephalitides of unknown cause by RT-PCR, prioritizing vaccine use for postexposure prophylaxis (PEP) during periods of vaccine shortage and subsequent expansion of PEP, surveillance of animal bites using information obtained from vaccine application, roll out of preexposure prophylaxis (PrEP) with vaccine stock restoration, surveillance for adverse events following immunization (AEFI), and ensuring surge capacity to respond to general public inquiries by phone and training for healthcare professionals. Enhanced surveillance for human rabies found no cases after testing 205 stored CSF specimens collected during January 2010-July 2013. During July 16 to December 28, 2013, we received 8,241 rabies PEP application; 6,634 (80.5%) were consistent with recommendations. Among the 6,501 persons who received at least one dose of rabies vaccine postexposure, 4,953 (76.2%) persons who were bitten by dogs; only 59 (0.9%) persons were bitten by ferret-badgers. During the study period, 6,247 persons received preexposure prophylaxis. There were 23 reports of AEFI; but no anaphylaxis, Guillain-Barré syndrome, or acute disseminated encephalomyelitis were found. During the study period, there were 40,312 calls to the Taiwan Centers for Disease Control hotline, of which, 8,692 (22%) were related to rabies. Recent identification of rabies among ferret-badgers in a previously rabies-free country prompted rapid response. To date, no human rabies has been identified. Continued multifaceted surveillance and interministerial collaboration are crucial to achieve the goal of rabies-free status in Taiwan.

Surveillance and vaccine effectiveness of an influenza epidemic predominated by vaccine-mismatched influenza B/Yamagata-lineage viruses in Taiwan, 2011-12 season.

INTRODUCTION: The 2011-12 trivalent influenza vaccine contains a strain of influenza B/Victoria-lineage viruses. Despite free provision of influenza vaccine among target populations, an epidemic predominated by influenza B/Yamagata-lineage viruses occurred during the 2011-12 season in Taiwan. We characterized this vaccine-mismatched epidemic and estimated influenza vaccine effectiveness (VE). METHODS: Influenza activity was monitored through sentinel viral surveillance, emergency department (ED) and outpatient influenza-like illness (ILI) syndromic surveillance, and case-based surveillance of influenza with complications and deaths. VE against laboratory-confirmed influenza was evaluated through a case-control study on ILI patients enrolled into sentinel viral surveillance. Logistic regression was used to estimate VE adjusted for confounding factors. RESULTS: During July 2011-June 2012, influenza B accounted for 2,382 (72.5%) of 3,285 influenza-positive respiratory specimens. Of 329 influenza B viral isolates with antigen characterization, 287 (87.2%) were B/Yamagata-lineage viruses. Proportions of ED and outpatient visits being ILI-related increased from November 2011 to January 2012. Of 1,704 confirmed cases of influenza with complications, including 154 (9.0%) deaths, influenza B accounted for 1,034 (60.7%) of the confirmed cases and 103 (66.9%) of the deaths. Reporting rates of confirmed influenza with complications and deaths were 73.5 and 6.6 per 1,000,000, respectively, highest among those aged ≥65 years, 50-64 years, 3-6 years, and 0-2 years. Adjusted VE was -31% (95% CI: -80, 4) against all influenza, 54% (95% CI: 3, 78) against influenza A, and -66% (95% CI: -132, -18) against influenza B. CONCLUSIONS: This influenza epidemic in Taiwan was predominated by B/Yamagata-lineage viruses unprotected by the 2011-12 trivalent vaccine. The morbidity and mortality of this vaccine-mismatched epidemic warrants careful consideration of introducing a quadrivalent influenza vaccine that includes strains of both B lineages.

Prospective observational study comparing three different treatment regimes in patients with Clostridium difficile infection.

In a hospital-based, prospective cohort study, the effects of the three standard treatment regimens for mild Clostridium difficile infection (CDI), oral (p.o.) metronidazole at 500 mg three times/day, intravenous (i.v.) metronidazole at 500 mg three times/day, and oral (p.o.) vancomycin at 250 mg four times/day, were compared with respect to the risk of occurrence of complications, sequelae, and all-cause death within 30 days after the date of starting treatment. Differences in the incidence of these outcomes were tested by χ² or Fisher's exact tests. A Poisson regression model was performed to control for possible confounding effects of sex, age, and severity of comorbidity categorized according to the Charlson comorbidity index. The highest mortality was observed in the metronidazole i.v. group, with a mortality rate 38.1% (16/42) compared to mortality rates of 7.4% (9/121) in the metronidazole p.o. group and 9.5% (4/42) in the vancomycin p.o. group (P < 0.001). After adjustment for possible effects of sex, age (> 65 years), and severity of comorbidity, the relative risk of a 30-day fatal outcome for patients receiving metronidazole i.v. was 4.3 (95% confidence interval [CI] = 1.92 to 10; P < 0.0001) compared to patients treated with metronidazole p.o. and 4.0 (95% CI = 1.31 to 5.0; P < 0.015) compared to patients treated with vancomycin p.o. There were no significant differences in the risk of complications between the three treatment groups. This study generates the hypothesis that treatment with i.v. metronidazole is inferior to the oral alternatives metronidazole and vancomycin.

Influenza-related excess mortality, Austria 2001 till 2009.

In Austria, a country with a total population of approximately 8.3 million, the published estimates of influenza-associated deaths within the past decade are surprisingly high (up to 6000 deaths per year) when compared to neighbouring countries. The objective of our analysis was to provide reliable estimates of the annual influenza-related deaths in Austria. We estimated the seasonal influenza-related excess mortality by calculating the difference between all-cause mortality observed during the influenza season and the baseline values to be expected during that time span if increased influenza activity was absent. Increased influenza activity was defined as moderate, usual or high, categorized by the influenza activity index using weekly data from the Austrian sentinel clinical surveillance system. For obtaining estimates of baseline all-cause mortality, a cyclic regression model was applied to the time series data on weekly all-cause mortality from 2001 to 2009. Austrian seasonal influenza-related excess mortality peaked in the seasons 2002/2003 (1060 excess deaths), 2004/2005 (1102 excess deaths) and 2008/2009 (1192 excess deaths). The rising trend observed is in parallel with the increasing proportion of the Austrian population older than 65 years for the same time span (2001:15.5%; 2009: 17.5%). Our findings on seasonal influenza-related excess mortality are in accordance with the estimates from Germany and Switzerland, which were derived from a similar approach. In order to gain and to preserve higher compliance with influenza vaccination initiatives, it is essential to have reliable data on influenza-related mortality. Thus, the numbers presented so far by Austrian public health institutions must be challenged.

Rubella in Austria 2008-2009: no longer a typical childhood disease.

BACKGROUND: In February 2009, a cluster of rubella cases was recognized in Austria occurring between calendar weeks 3 and 7, 2009 after a long period of low rubella virus activity. A nationwide 2-dose measles, mumps, and rubella vaccination program had been introduced in 1994 to prevent this childhood illness. METHODS: An epidemiologic investigation was conducted to describe the cluster by time, place, and person. A confirmed outbreak case was defined as a febrile person (1) with generalized rash, which was laboratory confirmed or epidemiologically linked to a laboratory confirmed case and (2) who became ill after October 1, 2008 in the 2 affected provinces. A probable outbreak case was defined as any person meeting the clinical criteria of rubella and meeting the criterion 2 of a confirmed outbreak case. All cases were telephone interviewed on demographics and vaccination status. RESULTS: A total of 355 outbreak cases (including 247 confirmed cases) occurred in 2 neighboring Austrian provinces from mid-October 2008 until the end of June 2009, peaking in mid-March. The 2 most-affected age groups were 15 to 19 (44.4%) and 20 to 24 year olds (32.4%). The vaccination status was available for 230 cases; 10% of cases had received 1 measles, mumps, and rubella vaccine dose. No case had received 2 doses. Of the 146 female cases, one laboratory-confirmed rubella infection in a pregnant 18-year-old native Austrian resulted in elective abortion. CONCLUSIONS: These findings underline the waning epidemiologic role of children in maintaining the circulation of rubella virus and indicate that additional vaccination activities targeting >15 year olds are needed to achieve the 2010 WHO target for rubella elimination in the European Region.

A non-foodborne norovirus outbreak among school children during a skiing holiday, Austria, 2007.

Norovirus is increasingly recognized as a leading cause of outbreaks of foodborne disease. We report on an outbreak in Austria that reached a total of 176 cases, affecting pupils and teachers from four schools on a skiing holiday in a youth hostel in the province of Salzburg in December 2007. A questionnaire was sent to the four schools in order to obtain data from persons attending the school trip on disease status, clinical onset, duration of illness and hospitalization. A cohort study was undertaken to identify the sources of infection. The school trip attendees were interviewed by questionnaire or face-to-face on their exposure to food items from the menu provided by the hostel owner. Of the 284 school holiday-makers, 176 fitted the definition of an outbreak case (attack rate 61.9%). A total of 264 persons on the ski holiday participated in the cohort study (response rate 93%). The day-by-day food-specific analyses did not find any food items served on any of five days (December 8-12) of the holiday to be associated with infection risk. The day-specific risk analyses revealed Monday December 10 (RR: 9.04; 95% CI: 6.02-13.6; P < 0.001) and Tuesday December 11 (RR: 3.37; 95% CI: 2.56-4.43; P < 0.001) as the two most risky days for having being exposed to norovirus. According to the epidemiological investigation, airborne transmission of norovirus originating from the first vomiting case most probably initiated this outbreak; foodborne genesis was excluded. During recent years, norovirus has become increasingly established as the most important causative agent of epidemic gastroenteritis in holiday-makers all over Europe. Tourism is one of the primary industries in Austria. Timely involvement of the relevant public health authorities is essential in any outbreak of norovirus gastroenteritis, irrespective of its genesis.

A food-borne outbreak of Shigella sonnei gastroenteritis, Austria, 2008.

We report on the first foodborne outbreak of Shigella sonnei described in Austria. On July 14 2008, AGES was informed of a cluster of 22 laboratory-confirmed cases of infection with S. sonnei restricted to public health district X in the province of Salzburg. All cases had attended a youth-group trip to a small village in the province of Tyrol from July 7 to July 9. An outbreak case among the trip participants was a person who (1) attended the trip and (2) fell ill with diarrhea in the period between July 8 and July 12. Among the 61 trip participants, 42 fitted the outbreak case definition, including 31 culture-confirmed cases. A household outbreak case was a person who (1) did not participate in the trip, (2) fell ill with diarrhea not before July 10 and (3) had household contact with an outbreak case between one and three days before onset of illness. Of the 11 household outbreak cases, 10 were tested by stool culture and four of these had a laboratory-confirmed S. sonnei infection. In addition, one of the two hostel staff tested positive for S. sonnei. All 36 isolates were biotype gl, lysotype 12, and were indistinguishable from each other by PFGE. A cohort study among the trip participants revealed a risk ratio of 2.71 for consumption of salad (on at least 1 of the 3 days of the trip) (95% CI: 1.38-5.32, P = 0.004). Among the 42cases, 34 could be explained by consumption of salad. The landlady of the hostel, who prepared the salad with bare hands, was a carrier and was assumed to be the source of contamination of the salad. Without proper epidemiological analytical investigation of this shigellosis outbreak, its association with food consumption would not have been identified.

A foodborne outbreak due to norovirus in Austria, 2007.

A foodborne norovirus outbreak occurred after a pre-Christmas celebration among a group of local foresters in Austria in December 2007. A total of 66 persons, 60 participants of the Christmas party and 6 kitchen staff members of the restaurant where the party took place, were identified as the at-risk cohort. Questioning of this cohort was performed by self-report questionnaires or telephone interviews (response rate of 95%). The outbreak attack rate was 33.3% (21 of 63 persons), including two of the kitchen staff. Three stool specimens yielded norovirus genogroup II. Univariate analysis revealed that exposure to a ham roll and pastry was possibly associated with risk of gastroenteritis (risk ratio [RR] of 4.45, 95% CI of 1.91 to 10. RR of 2.44, 95% CI of 0.93 to 6.39). After controlling for the effects of sex, age, and other food items with a log-linear model, ham roll remained significantly associated with disease risk (RR of 3.91, 95% CI of 1.57 to 9.76). Ham roll was most likely contaminated with norovirus during preparation by a disease-free kitchen assistant, whose infant became sick with laboratory-confirmed norovirus gastroenteritis 2 days before the party. Informing food handlers about the possible risk of food contamination with norovirus and training them in the appropriate measures of hand hygiene and environmental disinfection at the working place and at home are essential for preventing food-related norovirus outbreaks. Norovirus-infected household members of healthy food handlers must be considered a possible reservoir for foodborne norovirus outbreaks.

Hematological and biochemical factors predicting SARS fatality in Taiwan.

BACKGROUND/PURPOSE: Severe acute respiratory syndrome (SARS) has a high fatality rate worldwide. We examined the epidemiologic and clinical factors associated with death for all laboratory-confirmed SARS patients in Taiwan. METHODS: Using initial data in medical records reported by hospitals to the Center for Disease Control in Taiwan, we analyzed whether hematological, biochemical and arterial blood gas measures could predict fatality in 346 SARS patients. RESULTS: Both fatalities (n = 73; 21.1%) and survivors had elevated plasma concentration of initial C-reactive protein (CRP), but the mean CRP concentration was higher in fatalities (47.7 +/- 43.3 mg/L) than in survivors (24.6 +/- 28.2 mg/L). Initial lymphocyte counts were low in both fatalities (814 +/- 378/microL) and survivors (1019 +/- 480/microL). After controlling for age and sex, multiple logistic regression analysis showed that hematological factors significantly associated with fatality included initial neutrophil count > 7000/microL (odds ratio [OR] = 6.4), initial CRP concentration > 47.5 mg/L (OR = 5.8) and lactic acid dehydrogenase (LDH) > 593.5 IU/L (OR = 4.2). Factors significantly associated with initial CRP concentration > 47.5 mg/L included dyspnea (OR = 4.3), red blood cell count < 4.1 x 106/microL (OR = 4.3) and serum aspartate aminotransferase > 57 IU/L (OR = 3.1). CONCLUSION: Initial neutrophil count, CRP and LDH levels are important predictors of mortality from SARS.

Nasopharyngeal shedding of severe acute respiratory syndrome-associated coronavirus is associated with genetic polymorphisms.

BACKGROUND: A high initial or peak severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) load in nasopharyngeal specimens was shown to be associated with a high mortality rate. Because all infected individuals were devoid of preeexisting protective immunity against SARS-CoV, the biological basis for the variable virus burdens in different patients remains elusive. METHODS: The nationwide SARS database in Taiwan was analyzed, and genotyping of 281 single-nucleotide polymorphisms (SNPs) of 65 genes was performed for 94 patients with SARS, to identify SNPs for which distribution between patients with or without detectable nasopharyngeal shedding of SARS-CoV was biased. RESULTS: Titers of SARS-CoV shed in nasopharyngeal specimens varied widely, ranging from nondetectable to 10(8) SARS-CoV RNA copies/mL, and they were correlated positively with a high mortality rate (P<.0001, by trend test) and with early death (i.e., death occurring within 2 weeks of the onset of illness) (P=.0015, by trend test). Virus shedding was found to be higher among male patients (P=.0014, by multivariate logistic regression) and among older patients (P=.015, by multivariate logistic regression). Detectable nasopharyngeal shedding of SARS-CoV was associated with polymorphic alleles of interleukins 18 (P=.014) and 1A (P=.031) and a member of NF kappa B complex (reticuloendotheliosis viral oncogene homolog B [RelB]) (P=.034), all of which are proinflammatory in nature, as well as the procoagulation molecule fibrinogen-like protein 2 (P=.008). CONCLUSION: The SARS-CoV load is a determinant of clinical outcomes of SARS, and it is associated with polymorphisms of genes involved in innate immunity, which might be regulated in an age- and sex-dependent manner. The findings of the present study provided leads to genes involved in the host response to SARS-CoV infection; if substantiated with functional studies, these findings may be applicable to other newly emerged respiratory viruses (e.g., the influenza pandemic strain).

Roles of the minor pseudopilins, XpsH, XpsI and XpsJ, in the formation of XpsG-containing pseudopilus in Xanthomonas campestris pv. campestris.

Due to their similarity to type IV pilus (Tfp) subunits, the pseudopilins, XpsG, -H, -I, -J and -K, have been predicted to form a pilus-like structure in the type II secretion (T2S) pathway. While overexpression of GspG can result in the formation of bundle structures, the functions of other pseudopilin are not known yet. In this study, we investigate the mutual interaction among the pseudopilins and characterize the specialized minor pseudopilin, XpsJ. By using gel filtration and Ni-NTA affinity chromatography, a linearly ordered interactive relationship is revealed among the four pseudopilins, XpsG-XpsI-XpsH-XpsJ. Notably, unlike the mutant XpsJ194 staying in the inner membrane, wild type XpsJ stayed in the outer membrane and blocked the extension of overexpressed XpsG to outside of the cell. By analogy with the Type I pilus structures, we hypothesize that the XpsH and XpsI might act as an adaptor to connect XpsJ with the major pseudopilin XpsG, and XpsJ might act as a tip to restrict the out-growth of XpsG in the pilus-like structure of the T2S pathway.

Transmission of the severe acute respiratory syndrome on aircraft.

BACKGROUND: The severe acute respiratory syndrome (SARS) spread rapidly around the world, largely because persons infected with the SARS-associated coronavirus (SARS-CoV) traveled on aircraft to distant cities. Although many infected persons traveled on commercial aircraft, the risk, if any, of in-flight transmission is unknown. METHODS: We attempted to interview passengers and crew members at least 10 days after they had taken one of three flights that transported a patient or patients with SARS. All index patients met the criteria of the World Health Organization for a probable case of SARS, and index or secondary cases were confirmed to be positive for SARS-CoV on reverse-transcriptase polymerase chain reaction or serologic testing. RESULTS: After one flight carrying a symptomatic person and 119 other persons, laboratory-confirmed SARS developed in 16 persons, 2 others were given diagnoses of probable SARS, and 4 were reported to have SARS but could not be interviewed. Among the 22 persons with illness, the mean time from the flight to the onset of symptoms was four days (range, two to eight), and there were no recognized exposures to patients with SARS before or after the flight. Illness in passengers was related to the physical proximity to the index patient, with illness reported in 8 of the 23 persons who were seated in the three rows in front of the index patient, as compared with 10 of the 88 persons who were seated elsewhere (relative risk, 3.1; 95 percent confidence interval, 1.4 to 6.9). In contrast, another flight carrying four symptomatic persons resulted in transmission to at most one other person, and no illness was documented in passengers on the flight that carried a person who had presymptomatic SARS. CONCLUSIONS: Transmission of SARS may occur on an aircraft when infected persons fly during the symptomatic phase of illness. Measures to reduce the risk of transmission are warranted.