ABSTRACT
Introduction: The COVID-19 vaccination campaign was implemented in Sibu, Malaysia in February 2021. We assessed the effectiveness of the CoronaVac vaccine against severe acute respiratory infections (SARI) hospitalisation associated with laboratory-confirmed SARS-CoV-2 by time since vaccination. Method(s): A test-negative case-control design was employed using a web-based national information system for PCR results of SARS-CoV-2 infection and COVID-19 vaccination, and the hospitalisation dataset in Sibu Hospital. Eligible SARI cases with SARS-CoV-2 RT-PCR positive were matched to those SARI cases with negative RT-PCR tests by age and workplace. Vaccine effectiveness was measured by conditional logistic regression with adjustment for gender, comorbidity, smoking and education level. Result(s): Between 15 March and 30 September 2021, in the dominance of lineages B.1.466.2 and B.1.617.2 (Delta variant), a total of 838 eligible SARI patients were identified. Vaccine effectiveness was 42.4% (95% confidence interval [CI]: -28.3, 74.1), and 76.5% (95% CI: 45.6, 89.8) for partial vaccination (after the first dose through 14 days after the second dose) and complete vaccination (at 15 days or more after receipt of the second dose), respectively. Sensitivity analysis using propensity score matching yielded a conservative estimate of 57.4% (95% CI: 9.2, 80.1) for complete vaccination. Conclusion(s): Primary immunisation with two doses of CoronaVac vaccine provided satisfactory protection against SARI caused by SARS-CoV-2 in the short term. However, the duration of protection, incremental effectiveness induced by boosting, as well as performance against new variants need to be studied continuously.
ABSTRACT
The nucleic acid detection is an effective way for the prevention and control of COVID-19. PCR amplification is an important process in the nucleic acid detection. At present, PCR amplification has the problem of low heating/cooling rates, and poor temperature uniformity. This paper proposes a microchannel temperature control device for the nucleic acid detection. Five groups of parallel serpentine channels are used to increase the cooling rate of the PCR amplification. A gradual thermal conductivity design is applied to the reaction module to increase the temperature uniformity. The experimental results show that the best temperature uniformity is obtained when the materials of the inner and outer layers of the reaction module are copper and aluminum alloys, respectively. The limit and average heating/cooling rate are 7.2, 6.12, 5.52 and 5.28 °C/s, respectively, when the input power of the thermoelectric cooler is 11.07 W/cm2, the temperature and flow rate of the cooling water are 15℃ and 700 ml/min, and the thermal conductivity of the thermal grease is 6 W/(m·K). Compared with the commercial fan-fin cooling method, the limit and average heating/cooling rates are increased by 38.02%, 80.82%, 86.49% and 208.77%, respectively, with the help of microchannel cooling method. © 2023 Elsevier Ltd
ABSTRACT
The world is enduring difficulties in numerous fields because of this Coronavirus pandemic flare-up. All government had played it safe to forestall the infection transmission, for example, rehearsing social distancing and temperature checking before entering any preface just as declaring a lockdown. Notwithstanding, the 1-meter distance is not straightforward to estimate by unaided eyes, and it is difficult to carry along a meter rule regularly. Subsequently, inadvertently connect with others. Therefore, this would build our danger of getting contaminated by the COVID-19 infection. Moreover, the thermometer put at each person’s passageway has the threat of causing disease since numerous individuals share it. Regardless of whether a specialist is appointed to quantify guests’ temperature, the person does not have the option to keep up the guest’s social distance when taking temperature. In this research, a sensing bracelet proposed to determine physical distancing and temperature. The bracelet has two fundamental capacities. It can continually screen distance among client and others utilising a sensor. It will warn the client to keep up social distancing and avoid swarmed places when it distinguishes individuals under 1 meter. Second, it has a temperature sensor to determine the client’s internal heat level and will ring to caution the client if the internal heat level is more than 37.5°C. The experiment conducted able to achieve the requirement for a physical distancing.
ABSTRACT
Objective To explore the high risk factors associated with severity of coronavirus disease-2019 (COVID-19) to provide a basis for precise diagnosis and treatment. Methods The clinical data of COVID-19 patients admitted to Fuyang Second People's Hospital in Anhui Province from Jan. 20, 2020 to Feb. 13, 2020 were retrospectively analyzed. According to the progress of the disease or not, the patients were divided into stable group and severe group. Multivariate COX proportional hazards regression analysis and dynamic changes were used to assess the high-risk factors for exacerbation of the disease. Results Finally 143 confirmed patients with COVID-19 were enrolled, the average age was 43.5(32.7, 52.4) years, 81(56.6%) cases were male, 28(19.6%) cases had at least one comorbidity (underlying disease). The most common symptom was fever (119, 83.2%), followed by dry cough (77, 53.8%). Totally, 122 patients (85.3%) had continued improvement(stable group), and 21(14.7%) deteriorated within 2 weeks of symptoms onset (severe group). Multivariate COX proportional hazards regression analysis showed that age over 60 years (HR=3.5, 95% CI 1.4-9.0), combined with underlying diseases (HR=3.9, 95% CI 1.5-10.4), LDH>250.0 U/L (HR=4.1, 95% CI 1.4-12.6), and absolute lymphocyte count less than 1.0×109/L (HR=6.8, 95% CI 2.3-20.7) were high risk factors for COVID-19 patient deterioration. Conclusions Identification of high-risk factors for deterioration of COVID-19 can assist early detection of cases with severe tendency and develop individualized and precise treatment strategy, which might alleviate the shortage of medical resources and reduce mortality.