Investigation on the Control of COVID-19 in Wuhan: Number of Infections Outside Hospitals and the Reproduction Number.

COVID-19 is erupting globally, and Wuhan successfully controlled it within a month. Infections arose from infectious persons outside hospitals. After data revision, data-based and model-based analyses were implemented, and the conclusions are as follows. The incubation period of most infected people may be 6-7 days. The number of infectious persons outside hospitals in Wuhan on January 20, 2020 was about 10000 and reached more than 20000 on the day of Lockdown; it exceeded 72000 on February 4. Both data-based and model-based analyses gave out the evolution of the reproduction number, which was over 2.5 in early January, went down to 1.62 in late January and 1.20 in early February, with a sudden drop to less than 0.5 due to the strict Stay-at-home management after February 11. Strategies of Stay-at-home, Safe-protective measures, and Ark hospitals were the main contributions to control COVID-19 in Wuhan. In Wuhan, 2 inflection points of COVID-19, exactly correspond to February 5 and February 15, the 2 days when Ark hospitals were introduced, and the complete implementation of Stay-at-home. Based on the expression of the reproduction number, group immunity is also discussed. It shows that only when the group immunization rate is over 75% can COVID-19 be under control; group immunity would be full infection and the total deaths will be 220000 for a city as big as Wuhan. Sensitivity analysis suggests that 30% of people staying at home in combination with better behavior changes, such as social-distancing and frequent handwashing, can effectively contain COVID-19. However, only when this proportion is over 60% can the controlled effect and efficiency like Wuhan be obtained.

A Combined Method Based on the FIPV N Monoclonal Antibody Immunofluorescence Assay and RT-nPCR Method for the Rapid Diagnosis of FIP-Suspected Ascites

Feline infectious peritonitis (FIP), which is caused by feline infectious peritonitis virus (FIPV), is a fatal and immunologically mediated infectious disease among cats. At present, due to the atypical clinical symptoms and clinicopathological changes, the clinical diagnosis of FIP is still difficult. The gold standard method for the differential diagnosis of FIP is immunohistochemistry (IHC) which is time-consuming and requires specialized personnel and equipment. Therefore, a rapid and accurate clinical diagnostic method for FIPV infection is still urgently needed. In this study, based on the etiological investigation of FIPV in parts of southern China, we attempted to explore a new rapid and highly sensitive method for clinical diagnosis. The results of the etiological investigation showed that the N gene of the FIPV BS8 strain had the highest homology with other strains. Based on this, a specific FIPV BS8 N protein monoclonal antibody was successfully prepared by expression of the recombinant proteins, immunization of mice, fusion and selection of hybridoma cell lines, and screening and purification of monoclonal antibodies. Furthermore, we carried out a time-saving combination method including indirect immunofluorescence assay (IFA) and nested reverse transcription polymerase chain reaction (RT-nPCR) to examine FIP-suspected clinical samples. These results were 100% consistent with IHC. The results revealed that the combined method could be a rapid and accurate application in the diagnosis of suspected FIPV infection within 24 hours. In conclusion, the combination of IFA and RT-nPCR was shown to be a fast and reliable method for clinical FIPV diagnosis. This study will provide insight into the exploitation of FIPV N antibodies for the clinical diagnosis of FIP-suspected ascites samples.

Effects of vaccines on clinical characteristics of convalescent adult patients infected with SARS-CoV-2 Omicron variant: A retrospective study.

Introduction: The protective effect of SARS-CoV-2 vaccines has become a global focus due to Omicron variant pandemic. The effects of various SARS-CoV-2 vaccines are diverse. However, studies on the effect of domestic vaccines on clinical characteristics in convalescent adult patients infected with the Omicron variant are lacking. Methods: In this retrospective, single-center cohort study, the effect of three domestic vaccines on clinical characteristics of convalescent adult patients infected with the Omicron variant was investigated in the initial largest outbreak of the Omicron variant infection between January and February 2022 in Tianjin, China. The primary endpoint was COVID-19 severity and the secondary endpoints were re-positive results on nucleic acid tests, liver and kidney function, and inflammation levels during recovery. Results: A total of 320 adult patients infected with the Omicron variant were enrolled, including 296 post-vaccination and 24 unvaccinated patients. The median age of the unvaccinated patients was higher than that of vaccinated patients, but no significant difference was detected in the sex composition ratio between the different groups. Binary logistic regression results suggested that Sinopharm and Sinovac vaccine was an independent protective factor for relieving the severity of the Omicron variant infection. Regrettably, the vaccines did not showed any protective effect on the liver and kidney function of convalescent adult patients. Three domestic vaccines significantly relieved inflammation and increased the SARS-CoV-2-specific antibody levels. Furthermore, Sinovac and CanSino vaccines had a better immune stimulation effect on increasing T lymphocytes levels in convalescent adult patients. In addition, three domestic vaccines have protective effects on preventing re-detectable positive (RP) result in convalescent adult patients. Conclusion: Although the three domestic vaccines cannot prevent the infection of the Omicron variant, it has a significant protective effect in adult patients. This study supports the policy of accelerating to vaccination worldwide combat the evolving and mutating SARS-CoV-2. Discussion: Omicron spreads faster and might escape antibodies more readily than previous variants, increasing the cases of reinfection and breakthrough infections in vaccinated people. Although vaccinated people are likely to have a much lower risk of severe disease from Omicron infection, many issues still need to be considered. Concerns about lower vaccine efficacy because of new variants might have changed our understanding of the COVID-19 endgame, disabusing the world of the notion that global vaccination is by itself adequate for controlling SARS-CoV-2 infection. The current data showed that vaccination with three domestic SARS-CoV-2 vaccines alleviates the disease severity of adult patients with COVID-19, reduces the inflammation level and the RP rate of convalescent adult patients, and enhances body's defense against the virus in convalescent adult patients. Moreover, our study has highlighted that a combination prevention approach of vaccination and public health measures would be an effective strategy.

Comparison of clinical manifestations, liver function, and antibody levels between omicron variant infection patients vaccinated and not vaccinated with COVID-19 vaccine

Objective: To compare the clinical manifestations, liver function, and antibody levels between Omicron variant infection patients vaccinated and not vaccinated with COVID-19 vaccine. Methods: Totally 430 convalescent COVID-19 patients infected with Omicron variant in Tianjin were selected, including 150 patients vaccinated with Corona Vaccine(Sinovac group), 185 patients vaccinated with BBIBP-CorV(Beijing biological group), 41 patients vaccinated with Ad5-nCoV vaccine(CanSino group), 16 patients vaccinated with Anhui Zhifei, Changchun Bio, Lanzhou Bio, Shandong Bio, other adenovirus vector vaccines or mixed vaccination(other group), and 38 unvaccinated patients(unvaccinated group). The clinical manifestations, liver function indexes [alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TB), albumin(ALB), total protein(TP), lactate dehydrogenase(LDH)], and antibody levels(IgG, IgM)were compared retrospectively. Results: There was no statistical difference in the sex composition ratio among groups(P > 0.05). The age of the Beijing biological group was significantly lower than that of other groups, and the proportion of time less than 3 months from the last vaccination to admission in the Beijing biological group and CanSino group was significantly higher than that in the Sinovac group and other groups(all P < 0.01). A total of 110 children aged less than 16 years were enrolled, including 7, 88, 0, 1 and 14 cases in the Sinovac group, Beijing biological group, CanSino group, other group, and unvaccinated group, respectively. There were 6 asymptomatic cases, 13 moderate cases, 91 mild cases and 0 severe case. There was no significant difference in the abnormal rate of ALT between Beijing biological group and unvaccinated group(P > 0.05), but the abnormal rates of ALT were higher in the Sinovac group and CanSino group than in the unvaccinated group and Beijing biological group(all P < 0.05). The abnormal rate of AST in the unvaccinated group was higher than that in other groups(P < 0.05). There were no significant differences in AST, TP or TB among the groups(all P > 0.05). The levels of ALT were higher in the Sinovac group and CanSino group than in Beijing biological Group and unvaccinated group, the level of ALB in the unvaccinated group was lower than that in the other groups, and the level of LDH in the Beijing biological group was higher than those in the Sinovac group and CanSino group(both P < 0.05). The IgG and IgM antibody levels of the unvaccinated group were significantly lower than those of the Sinovac group, Beijing biological group and CanSino group(all P < 0.05). Conclusions: Omicron variant infection patients vaccinated with BBIBP-CorV are younger and have a higher proportion of mild conditions, which can protect the liver function of patients to a certain extent. Patients vaccinated with different COVID-19 vaccines can produce higher levels of IgG and IgM antibodies than the unvaccinated patients.

Applying two behavioral theories to predict the willingness to receive COVID-19 vaccine booster in the elderly: A cross-sectional study.

BACKGROUND: The COVID-19 vaccination booster can effectively protect the elderly from infection while also lowering the risk of serious illness and death. However, barriers remain in willingness of the elderly to boost vaccination. OBJECTIVE: Using the protection motivation theory (PMT) and the theory of planned behavior (TPB), to study the factors that influence willingness of the elderly to get the COVID-19 vaccine booster. METHODS: The elderly who visited three randomly selected medical institutions in Nanjing's core urban region between March and April 2022 were chosen as study participants. A face-to-face survey was conducted using purposeful sampling and a self-designed questionnaire. The questionnaire contained sociodemographic characteristics, the elderly's willingness to obtain a COVID-19 vaccine booster, and psychosocial cognitive components based on the PMT and TPB. SmartPLS 3.0 was used to conduct structural equation modeling. RESULTS: 214 participants were included in the analysis. The combined model of the two behavioral theories explained the willingness to accept COVID-19 vaccine booster well with R2 of 0.490. Self-efficacy (ß = 0.315) was the strongest predictor of vaccine booster willingness. Subjective norms (ß = 0.160), perceived severity (ß = 0.157), and perceived vulnerability (ß = 0.159) also showed positive effects on vaccine booster willingness, while response cost (ß = -0.143) had a negative effect on the willingness. No significant association between attitudes, response efficacy and the willingness was discovered. CONCLUSION: The willingness of the elderly to receive the COVID-19 vaccine booster was affected by psychosocial cognitive factors. This study supports the applicability of the PMT and TPB models to interpret the willingness of the elderly in such areas.

The worldwide coronavirus disease 2019 outbreak: Advice and recommendation on radiology management and infection control from makeshift hospitals in Wuhan.

ABSTRACT: To describe and advise on management protocols and infection-protection experience of the radiology department in makeshift hospitals in Wuhan during the coronavirus disease 2019 (COVID-19) outbreak.Based on the literature review and the experience in the frontline, we retrospectively reviewed the configuration of the radiology department, human resource, personal protection, examination procedures for patients confirmed with COVID-19 in Wuhan fangcang shelter hospital.From February 11, 2020 to March 10, 2020, 2730 and 510 CT examinations were performed in the Hanjiang shelter hospital and Hanyang Sports School shelter hospital, respectively, including initial examinations and re-examinations. The maximum number of daily CT examinations reached 289. The CT scanned a patient approximately once every 13 mins.Fangcang shelter radiology department could be powerful components of both global and national responses to the COVID-19 pandemic.

Clinical and immunological features of convalescent pediatric patients infected with the SARS-CoV-2 Omicron variant in Tianjin, China.

COVID-19 has spread surprisingly fast worldwide, and new variants continue to emerge. Recently, the World Health Organization acknowledged a new mutant strain "Omicron", with children were accounting for a growing share of COVID-19 cases compared with other mutant strains. However, the clinical and immunological characteristics of convalescent pediatric patients after Omicron infection were lacking. In this study, we comparatively analyzed the clinical data from pediatric patients with adult patients or healthy children and the effects of SARS-CoV-2 vaccine on the clinical and immune characteristics in convalescent pediatric patients. Our results indicated that convalescent pediatric patients had unique clinical and immune characteristics different from those of adult patients or healthy children, and SARS-CoV-2 vaccination significantly affected on the clinical and immune characteristics and the prevention of nucleic acid re-detectable positive (RP) in convalescent patients. Our study further deepens the understanding of the impact of Omicron on the long-term health of pediatric patients and provides a valuable reference for the prevention and treatment of children infected with Omicron.

Clinical characteristics and risks of the convalescent COVID-19 patients with re-detectable positive RNA test: a 430 patients with Omicron infected cross-sectional survey in Tianjin, China.

BACKGROUND: The outbreak of severe acute respiratory syndrome coronavirus (SARS-CoV-2) Omicron variant occurred in Tianjin, China, at the beginning of 2022. In the present study, we identified risk factors that may affect positive (RP) RNA re-testing in recovered patients infected with Omicron variants during recovery in hospital. METHODS: We retrospectively analyzed the medical records of 425 patients with Omicron variant infection admitted to our medical center from January 21, 2022 to February 24, 2022, based on the recurrence of RT-PCR positive results for SARS-CoV-2 after cure and discharge. Patients were divided into re-tested positive (RP) and non-re-detectable positive patients (NRP) groups, and clinical data from both groups were analyzed to investigate the characteristics and risk factors of RP patients. RESULTS: Univariate analysis showed significant differences in age, vaccination rate and dose, partial signs and symptoms, most co-existing disorders, and levels of CRP and IL-6 between the RP and NRP groups (all P < 0.05), while multifactorial logistic regression analysis showed that vaccination status and levels of IL-6 were independent risk factors for RP patients. CONCLUSION: Our results suggested that clinicians should assess the probability of "re-positive" nucleic acid tests after discharge, taking the following indicators into account: pre-admission underlying diseases, unvaccinated status, and high levels of CRP and IL-6. Post-discharge isolation and follow-up should also be strengthened.

Clinical and immunological features of convalescent pediatric patients infected with the SARS-CoV-2 Omicron variant in Tianjin, China

COVID-19 has spread surprisingly fast worldwide, and new variants continue to emerge. Recently, the World Health Organization acknowledged a new mutant strain "Omicron", with children were accounting for a growing share of COVID-19 cases compared with other mutant strains. However, the clinical and immunological characteristics of convalescent pediatric patients after Omicron infection were lacking. In this study, we comparatively analyzed the clinical data from pediatric patients with adult patients or healthy children and the effects of SARS-CoV-2 vaccine on the clinical and immune characteristics in convalescent pediatric patients. Our results indicated that convalescent pediatric patients had unique clinical and immune characteristics different from those of adult patients or healthy children, and SARS-CoV-2 vaccination significantly affected on the clinical and immune characteristics and the prevention of nucleic acid re-detectable positive (RP) in convalescent patients. Our study further deepens the understanding of the impact of Omicron on the long-term health of pediatric patients and provides a valuable reference for the prevention and treatment of children infected with Omicron.

Flow Experiences and Virtual Tourism: The Role of Technological Acceptance and Technological Readiness

Virtual technology has brought new development opportunities to the tourism market and is expected to help the tourism industry cope with the challenges issuing from the COVID-19 pandemic. Given this context, in this study, we propose and test a model based on the SOR architecture, which includes tourists' experience of virtual tourism, technical readiness (TR), technical acceptance (TA), and tourists' virtual tourism intentions and the variables of flow experience, technical optimism, technical discomfort, perceived usefulness, perceived ease of use, adoption intention, and consumption intention. To this end, data were collected through a questionnaire survey of Chinese tourists (n = 542). Then, we used a structural equation model (SEM) to test the hypothetical relationships between potential variables. The results showed that the flow experience delivered by the virtual tourism experience affects tourists' tendencies to use and intentions to consume virtual tourism. Second, flow experiences can make tourists more optimistic about virtual tourism technology, reduce tourists' technical discomfort, and enhance tourists' perceptions of usefulness and ease of use. We also found that tourists' intentions to use virtual tourism technology affect their intentions to travel on the spot. These findings provide useful insights for tourism practitioners, suggest new ideas for marketing and sustainable development in the virtual tourism industry, and verify the application of the integrated SOR and TAM framework in the field of tourism consumption.

Analyzing an Epidemic of Human Infections with Two Strains of Zoonotic Virus

Due to the existence and variation of various viruses, an epidemic in which different strains spread at the same time will occur. here, an avian–human epidemic model with two strain viruses are established and analyzed. Both theoretical and simulation results reveal that the mixed infections intensify the epidemic and the dynamics become more complex and sensitive. There are six equilibria. The trivial equilibrium point is a high-order singular point and will undergo the transcritical bifurcations to bifurcate three equilibria. The existence and stability of equilibria mainly depend on five thresholds. A bifurcation portrait for the existence and stability of equilibria is presented. Simulations suggest that the key control measure is to develop the identification technology to eliminate the poultry infected with a high pathogenic virus preferentially, then the infected poultry with a low pathogenic virus in the recruitment and on farms. Controlling contact between human and poultry can effectively restrain the epidemic and controlling contagions in poultry can avoid great infection in humans.