Comparing hybrid and regular COVID-19 vaccine-induced immunity against the Omicron epidemic

Evidence on the effectiveness of COVID-19 vaccines among people who recovered from a previous SARS-CoV-2 infection is warranted to inform vaccination recommendations. Using the territory-wide public healthcare and vaccination records of over 2.5 million individuals in Hong Kong, we examined the potentially differential risk of SARS-CoV-2 infection, hospitalization, and mortality between those receiving two homologous doses of BNT162b2 or CoronaVac versus those with a previous infection receiving only one dose amid the Omicron epidemic. Results show a single dose after a SARS-CoV-2 infection is associated with a lower risk of infection (BNT162b2: adjusted incidence rate ratio [IRR] = 0.475, 95% CI: 0.410–0.550; CoronaVac: adjusted IRR = 0.397, 95% CI: 0.309–0.511) and no significant difference was detected in the risk of COVID-19-related hospitalization or mortality compared with a two-dose vaccination regimen. Findings support clinical recommendations that those with a previous infection could receive a single dose to gain at least similar protection as those who received two doses without a previous infection

Effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain

BackgroundWe evaluated the effects of varying blood flow rate during peripheral veno-arterial extracorporeal membrane oxygen (V-A ECMO) on left ventricular function measured by two-dimensional strain.MethodsAdult patients who were supported by peripheral V-A ECMO were recruited. Serial hemodynamic and cardiac performance parameters were measured by transthoracic echocardiogram within the first 48 h after implementation of V-A ECMO. Measurements at 100%, 120%, and 50% of target blood flow (TBF) were compared.ResultsA total of 54 patients were included and the main indications for V-A ECMO were myocardial infarction [32 (59.3%)] and myocarditis [6 (11.1%)]. With extracorporeal blood flow at 50% compared with 100% TBF, the mean arterial pressure was lower [66 ± 19 vs. 75 ± 18 mmHg, p < 0.001], stroke volume was greater [23 (12–34) vs. 15 (8–26) ml, p < 0.001], and cardiac index was higher [1.2 (0.7–1.7) vs. 0.8 (0.5–1.3) L/min/m2, p < 0.001]. Left ventricular contractile function measured by global longitudinal strain improved at 50% compared with 100% TBF [−2.8 (−7.6- −0.1) vs. −1.2 (−5.2–0) %, p < 0.001]. Similarly, left ventricular ejection fraction increased [24.4 (15.8–35.5) vs. 16.7 (10.0–28.5) %, p < 0.001] and left ventricular outflow tract velocity time integral increased [7.7 (3.8–11.4) vs. 4.8 (2.5–8.5) cm, p < 0.001]. Adding echocardiographic parameters of left ventricular systolic function to the Survival After Veno-arterial ECMO (SAVE) score had better discriminatory value in predicting eventual hospital mortality (AUROC 0.69, 95% CI 0.55–0.84, p = 0.008) and successful weaning from V-A ECMO (AUROC 0.68, 95% CI 0.53–0.83, p = 0.017).ConclusionIn the initial period of V-A ECMO support, measures of left ventricular function including left ventricular ejection fraction and global longitudinal strain were inversely related to ECMO blood flow rate. Understanding the heart-ECMO interaction is vital to interpretation of echocardiographic measures of the left ventricle while on ECMO

Real-World Effectiveness and Safety of Tixagevimab-Cilgavimab: A Target Trial Emulation Study

Background: Immunocompromised individuals are at high risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and subsequent severe or fatal coronavirus disease 2019 (COVID-19), yet they have suboptimal responses to mRNA and inactivated COVID-19 vaccines. The efficacy of tixagevimab–cilgavimab in reducing symptomatic SARS-CoV-2 infection was demonstrated in phase III clinical trials. Nevertheless, real-world data on the effectiveness and safety of tixagevimab–cilgavimab remain limited. Objective: The aim was to evaluate the effectiveness and safety of tixagevimab–cilgavimab among immunocompromised individuals. Methods: Adults who were immunocompromised or receiving immunosuppressive therapies were included in this target trial emulation using territory-wide electronic health records in Hong Kong. A sequential trial emulation approach was adopted to compare effectiveness and safety outcomes between individuals who received tixagevimab–cilgavimab and individuals who did not. Results: A total of 746 tixagevimab–cilgavimab recipients and 2980 controls were included from 1 May 2022 to 30 November 2022. Tixagevimab–cilgavimab significantly reduced the risk of COVID-19 infection (hazard ratio [HR] 0.708, 95% confidence interval [CI] 0.527–0.951) during a median follow-up of 60 days. No significant difference was observed in the risk of COVID-19-related hospitalisation. Zero versus eight COVID-19 mortality cases and zero versus two severe COVID-19 cases were observed in tixagevimab–cilgavimab recipients and controls, respectively. Notably, significant risk reduction in COVID-19 infection was also observed among immunocompromised individuals who had been previously vaccinated with three or more doses of COVID-19 vaccine, or had no prior COVID-19 infection history. Conclusions: Tixagevimab–cilgavimab was effective in reducing COVID-19 infection among immunocompromised patients during the Omicron wave. Findings were consistent among individuals who previously received three or more doses of COVID-19 vaccine, or had no previous history of COVID-19 infection

Perception of urban park soundscape

A number of studies have been initiated to explore how to improve the soundscape quality in urban parks. However, good soundscape quality in parks cannot be provided without a thorough understanding of the complex relationships among sound, environment, and individuals. As acoustic comfort is considered to be an important outcome of soundscape quality, this study investigates the relative impacts of the factors influencing acoustic comfort evaluation by formulating a multivariate ordered logit model. This study also explores the inter-relationships among acoustic comfort evaluation, acceptability of the environment, and preference to stay in a park using a path model. A total of 595 valid responses were obtained from interview surveys administered in four parks in Hong Kong while objective sound measurements were carried out at the survey spots concurrently. The findings unveil that acoustic comfort evaluation, besides visual comfort evaluation of landscape, also plays an important role on users’ acceptability of the urban park environment. Compared with all the studied acoustic related factors, acoustic comfort evaluation serves as a better proxy for park users’ preference to stay in urban parks. Hearing the breeze will significantly increase the likelihood of individuals in giving high acoustic comfort evaluation. Conversely, hearing the sounds from heavy vehicles or sounds from bikes will significantly reduce the likelihood in giving a high acoustic evaluation.Department of Building Services EngineeringDepartment of Mechanical Engineerin

Comparative Effectiveness and Safety of BNT162b2 and CoronaVac in Hong Kong: A Target Trial Emulation

OBJECTIVES: To evaluate the difference between BNT162b2 and CoronaVac in vaccine effectiveness and safety. METHODS: This target trial emulation study included individuals aged ≥ 12 during 2022. Propensity score matching was applied to ensure group balance. The Cox proportional hazard model was used to compare the effectiveness outcomes including COVID-19 infection, severity, 28-day hospitalization and 28-day mortality after infection. Poisson regression was used for safety outcomes including 32 adverse events of special interests between groups. RESULTS: 639,818 and 1,804,388 individuals were identified for the 2-dose and 3-dose comparison, respectively. In 2-dose and 3-dose comparison, the hazard ratios (HRs) (95% confidence intervals [CI]) were 0.844 [0.833-0.856] and 0.749 [0.743-0.755] for COVID-19 infection, 0.692 [0.656-0.731] and 0.582 [0.559-0.605] for hospitalization, 0.566 [0.417-0.769] and 0.590 [0.458-0.76] for severe COVID-19, and 0.563 [0.456-0.697] and 0.457 [0.372-0.561] for mortality for BNT162b2 recipients versus CoronaVac recipients, respectively. Regarding safety, 2-dose BNT162b2 recipients had a significantly higher incidence of myocarditis (Incidence rate ratio[IRR][95% CI]: 8.999 [1.14-71.017]) versus CoronaVac recipients, but the difference was insignificant in 3-dose comparison (IRR [95% CI]: 2.000 [0.500-7.996]). CONCLUSIONS: BNT162b2 has higher effectiveness among individuals aged ≥ 12 against COVID-19-related outcomes for SARS-CoV-2 omicron compared to CoronaVac, with almost 50% lower mortality risk. (200 words)

Effectiveness of molnupiravir vs nirmatrelvir-ritonavir in non-hospitalised and hospitalised patients with COVID-19: a target trial emulation study

BACKGROUND: Molnupiravir and nirmatrelvir-ritonavir have emerged as promising options for COVID-19 treatment, but direct comparisons of their effectiveness have been limited. This study aimed to compare the effectiveness of these two oral antiviral drugs in non-hospitalised and hospitalised patients with COVID-19. METHODS: In this target trial emulation study, we used data from a territory-wide electronic health records database on eligible patients aged ≥18 years infected with COVID-19 who were prescribed either molnupiravir or nirmatrelvir-ritonavir within five days of infection between 16 March 2022 and 31 December 2022 in the non-hospitalised and hospitalised settings in Hong Kong. A sequence trial approach and 1:1 propensity score matching was applied based on age, sex, number of COVID-19 vaccine doses received, Charlson comorbidity index, comorbidities, and drug use within past 90 days. Cox regression adjusted with patients' characteristics was used to compare the risk of effectiveness outcomes (all-cause mortality, intensive care unit (ICU) admission or ventilatory support and hospitalisation) between groups. Subgroup analyses included age (<70; ≥70 years); sex, Charlson comorbidity index (<4; ≥4), and number of COVID-19 vaccine doses received (0-1; ≥2 doses). FINDINGS: A total of 63,522 non-hospitalised (nirmatrelvir-ritonavir: 31,761; molnupiravir: 31,761) and 11,784 hospitalised (nirmatrelvir-ritonavir: 5892; molnupiravir: 5892) patients were included. In non-hospitalised setting, 336 events of all-cause mortality (nirmatrelvir-ritonavir: 71, 0.22%; molnupiravir: 265, 0.83%), 162 events of ICU admission or ventilatory support (nirmatrelvir-ritonavir: 71, 0.22%; molnupiravir: 91, 0.29%), and 4890 events of hospitalisation (nirmatrelvir-ritonavir: 1853, 5.83%; molnupiravir: 3037, 9.56%) were observed. Lower risks of all-cause mortality (absolute risk reduction (ARR) at 28 days: 0.61%, 95% CI: 0.50-0.72; HR: 0.43, 95% CI: 0.33-0.56) and hospital admission (ARR at 28 days: 3.73%, 95% CI: 3.31-4.14; HR: 0.72, 95% CI: 0.67-0.76) were observed in nirmatrelvir-ritonavir users compared to molnupiravir users. In hospitalised setting, 509 events of all-cause mortality (nirmatrelvir-ritonavir: 176, 2.99%; molnupiravir: 333, 5.65%), and 50 events of ICU admission or ventilatory support (nirmatrelvir-ritonavir: 26, 0.44%; molnupiravir: 24, 0.41%) were observed. Risk of all-cause mortality was lower for nirmatrelvir-ritonavir users than for molnupiravir users (ARR at 28 days: 2.66%, 95% CI: 1.93-3.40; HR: 0.59, 95% CI: 0.49-0.71). In both settings, there was no difference in the risk of intensive care unit admission or ventilatory support between groups. The findings were consistent across all subgroup's analyses. INTERPRETATION: Our analyses suggest that nirmatrelvir-ritonavir was more effective than molnupiravir in reducing the risk of all-cause mortality in both non-hospitalised and hospitalised patients. When neither drug is contraindicated, nirmatrelvir-ritonavir may be considered the more effective option

The role of SO2 in the reduction of NO by CO on La2O2S

The decomposition of NO and the reduction of NO by CO on La2O2S were studied using temperature-programmed reaction technique coupled with fast mass spectrometry, powder X-ray diffraction and X-ray photoelectron spectroscopy. The role of SO2 plays in the reduction is explored. It is found that the decomposition of NO is a favorable reaction step for the reduction of NO by CO achieved through a sulfur-assisted path. The oxygen produced in the decomposition is removed by the sulfur in the oxysulfide as SO2, which in turn is reduced back to sulfur by CO on La2O2S. An external supply of sulfur, such as SO2, in the feed is needed to maintain the population of sulfur in the oxysulfide and thus make the reduction sustainable. (c) 2006 Elsevier Inc. All rights reserved

The effect of H2O on the reduction of SO2 and NO by CO on La2O2S

The effect of H2O on the catalytic reduction of SO2 and NO on La2O2S was Studied using temperature-programmed reaction coupled with fast mass spectrometry, powder X-ray diffraction and X-ray photoelectron spectroscopy. It is found that La2O2S can be completely and irreversibly deactivated in the presence of H2O at 700 degrees C when NO/SO2 is sufficiently high (similar to 1.0). This is caused by the formation of a layer of inactive and stable La2O2SO4 on the oxysulfide. When NO is absent or NO/SO2 is low (similar to 0.4), H2O inhibits the reduction and shifts the selectivity from sulfur to H2S. While the causes of the deactivation can be attributed to the Reverse Claus Reaction between H20 and sulfur in the oxysulfide, the competitive hydrolysis of the COS intermediate and the competitive adsorption of H2O, the shift in selectivity to H2S is attributable to the former two factors. (c) 2007 Elsevier B.V. All rights reserved

A microscopic study of the effects of particle size and composition of atmospheric aerosols on the corrosion of mild steel

A novel approach to measure the corrosion effects of aerosols as a function of their aerodynamic size and chemical composition was used to study the effects of atmospheric aerosols on mild steel at a rural coastal site. The technique uses collocated micro-orifice uniform deposition impactor samplers to deposit ambient atmospheric particles on exposure steel coupons and collect aerosol samples for ionic analyses. Rusts were found on the coupons with aerosols but none on the blank coupons even the blanks were incubated at the same conditions. FTIR analysis shows that the composition of rusts changes gradually with the aerosol particle size. (c) 2008 Elsevier Ltd. All rights reserved

Size distributions and condensation growth of submicron particles in on-road vehicle plumes in Hong Kong

Volume concentration data of submicron particles (0.1 - 1.0 mu m) in on-road vehicle plumes (NOx > 400 ppb) gathered by the Mobile Real-time Air Monitoring Platform (MAP) on city streets, highways and in tunnels in Hong Kong are used to study the size distributions and growth of vehicular submicron particles due to gas condensation and, particularly, its dependency on ambient temperature. Three particle volume size distributions are observed: a uni-modal distribution with an accumulation mode at 0.2 +/- 0.1 mu m, and two bi-modal distributions with a minor mode at 0.2 +/- 0.1 mu m and the dominant mode at either 0.5 +/- 0.1 or 0.7 +/- 0.1 pm. In tunnels, the ratio of particle volume concentration to black carbon (BC) mass concentration correlates negatively with ambient temperature (r(2) = 0.57); the dominant mode tends to be at the large particle size when the temperature is low, and when the temperature is high, the uni-mode appears at the small particle size. Thus temperature seems to exert a significant influence on the condensation growth of fresh vehicular particles. On the other hand, this ratio correlates positively with ambient particle concentrations (r(2) = 0.35). Ambient particles measured in this study are mostly > 0.3 mu m while BC in vehicle plumes is generally believed to be mainly in the <0.3 pm size range in the literature. Temperature-dependent gas-condensation competition between fresh BC and ambient particles is suggested to play a role in the bi-modal formation. (C) 2007 Elsevier Ltd. All rights reserved