A Probabilistic Description of the Impact of Vaccine-Induced Immunity in the Dynamics of COVID-19 Transmission

The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.

The origin, transmission and clinical therapies on coronavirus disease 2019(COVID-19) outbreak——an update on the status

An acute respiratory disease,caused by a novel coronavirus(SARS-CoV-2,previously known as 2019-nCoV),the coronavirus disease 2019(COVID-19)has spread throughout China and received worldwide attention.On 30 January 2020,World Health Organization(WHO)officially declared the COVID-19 epidemic as a public health emergency of international concern.The emergence of SARS-CoV-2,since the severe acute respiratory syndrome coronavirus(SARSCoV)in 2002 and Middle East respiratory syndrome coronavirus(MERS-CoV)in 2012,marked the third introduction of a highly pathogenic and large-scale epidemic coronavirus into the human population in the twenty-first century.As of 1 March 2020,a total of 87,137 confirmed cases globally,79,968 confirmed in China and 7169 outside of China,with 2977 deaths(3.4%)had been reported by WHO.Meanwhile,several independent research groups have identified that SARS-CoV-2 belongs toβ-coronavirus,with highly identical genome to bat coronavirus,pointing to bat as the natural host.The novel coronavirus uses the same receptor,angiotensin-converting enzyme 2(ACE2)as that for SARS-CoV,and mainly spreads through the respiratory tract.Importantly,increasingly evidence showed sustained human-tohuman transmission,along with many exported cases across the globe.The clinical symptoms of COVID-19 patients include fever,cough,fatigue and a small population of patients appeared gastrointestinal infection symptoms.The elderly and people with underlying diseases are susceptible to infection and prone to serious outcomes,which may be associated with acute respiratory distress syndrome(ARDS)and cytokine storm.Currently,there are few specific antiviral strategies,but several potent candidates of antivirals and repurposed drugs are under urgent investigation.In this review,we summarized the latest research progress of the epidemiology,pathogenesis,and clinical characteristics of COVID-19,and discussed the current treatment and scientific advancements to combat the epidemic novel coronavirus.

Perceived infection transmission routes, infection control practices, psychosocial changes, and management of COVID-19 infected healthcare workers in a tertiary acute care hospital in Wuhan: a cross-sectional survey

Background:Many healthcare workers were infected by coronavirus disease 2019(COVID-19)early in the epidemic posing a big challenge for epidemic control.Hence,this study aims to explore perceived infection routes,influencing factors,psychosocial changes,and management procedures for COVID-19 infected healthcare workers.Methods:This is a cross-sectional,single hospital-based study.We recruited all 105 confirmed COVID-19 healthcare workers in the Zhongnan Hospital of Wuhan University from February 15 to 29,2020.All participants completed a validated questionnaire.Electronic consent was obtained from all participants.Perceived causes of infection,infection prevention,control knowledge and behaviour,psychological changes,symptoms and treatment were measured.Results:Finally,103 professional staff with COVID-19 finished the questionnaire and was included(response rate:98.1%).Of them,87 cases(84.5%)thought they were infected in working environment in hospital,one(1.0%)thought their infection was due to the laboratory environment,and 5(4.9%)thought they were infected in daily life or community environment.Swab of throat collection and physical examination were the procedures perceived as most likely causing their infection by nurses and doctors respectively.Forty-three(41.8%)thought their infection was related to protective equipment,utilization of common equipment(masks and gloves).The top three first symptoms displayed before diagnosis were fever(41.8%),lethargy(33.0%)and muscle aches(30.1%).After diagnosis,88.3%staff experienced psychological stress or emotional changes during their isolation period,only 11.7%had almost no emotional changes.Arbidol(Umifenovir;an anti-influza drug;69.2%)was the drug most commonly used to target infection in mild and moderate symptoms.Conclusion:The main perceived mode of transmission was not maintaining protection when working at a close distance and having intimate contact with infected cases.Positive psychological intervention is necessary.

Clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan

BACKGROUND Coronavirus disease 2019(COVID-19)has become a worldwide pandemic.We investigated the clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan by retrospectively analyzing the epidemiological,clinical,and laboratory data for 218 COVID-19 patients and identifying the risk factors for liver injury by multivariate analysis.AIM To investigate the clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan.METHODS The 218 patients included 94 males(43.1%),aged 22 to 94(50.1±18.4)years.Elevated aspartate aminotransferase(AST)and alanine aminotransferase(ALT)were present in 42(53.2%)and 36(45.6%)cases,respectively,and 79(36.2%)patients had abnormally elevated transaminase levels at admission.Patients with liver injury were older than those with normal liver function by a median of 12 years,with a significantly higher frequency of males(68.4%vs 28.8%,P<0.001)and more coexisting illnesses(48.1%vs 27.3%,P=0.002).Significantly more patients had fever and shortness of breath(87.3%vs 69.8%and 29.1%vs 14.4%,respectively)in the liver injury group.Only 12(15.2%)patients had elevated total bilirubin.ALT and AST levels were mildly elevated[1-3×upper limit of normal(ULN)]in 86.1%and 92.9%of cases,respectively.Only two(2.5%)patients had an ALT or AST level>5×ULN.Elevatedγ-glutamyl transpeptidase was present in 45(57.0%)patients,and 86.7%of these had aγ-glutamyl-transpeptidase level<135 U/L(3×ULN).Serum alkaline phosphatase levels were almost normal in all patients.Patients with severe liver injury had a significantly higher frequency of abnormal transaminases than non-severe patients,but only one case had very high levels of aminotransferases.RESULTS Multivariate analysis revealed that male sex,high D-dimer level,and high neutrophil percentage were linked to a higher risk of liver injury.The early stage of COVID-19 may be associated with mildly elevated aminotransferase levels in patients in Wuhan.Male sex and high D-dimer level and neutrophil percentage may be important predictors of liver injury in patients with COVID-19.CONCLUSION Male sex and high D-dimer level and neutrophil percentage may be important predictors of liver injury in patients with COVID-19.

Modeling the transmission dynamics of COVID-19 epidemic: a systematic review

The outbreak and rapid spread of COVID-19 has become a public health emergency of international concern.A number of studies have used modeling techniques and developed dynamic models to estimate the epidemiological parameters,explore and project the trends of the COVID-19,and assess the effects of intervention or control measures.We identified 63 studies and summarized the three aspects of these studies:epidemiological parameters estimation,trend prediction,and control measure evaluation.Despite the discrepancy between the predictions and the actuals,the dynamic model has made great contributions in the above three aspects.The most important role of dynamic models is exploring possibilities rather than making strong predictions about longer-term disease dynamics.

Assessment of COVID-19 aerosol transmission in a university campus food environment using a numerical method

With the prevalence of COVID-19,the phenomenon of viruses spreading through aerosols has become a focus of attention.Diners in university dining halls have a high risk of exposure to respiratory droplets from others without the protection of face masks,which greatly increases the risk of COVID-19 transmission.Therefore,the transmission mechanism of respiratory droplets in extremely crowded dining environments should be investigated.In this study,a numerical simulation of coughing at dining tables under two conditions was performed,namely the presence and absence of protective partitions,and the evaporation and condensation of aerosol droplets in the air were examined.By using the numerical method,we analyzed and verified the isolation effect of dining table partitions in the propagation of aerosol droplets.The effect of changes in room temperature on the diffusion of coughed aerosols when partitions were present was analyzed.We demonstrated how respiratory droplets spread through coughing and how these droplets affect others.Finally,we proposed a design for a dining table partition that minimizes the transmission of COVID-19.

Eliminating Mother-to-Child Transmission of Syphilis: Chinese Practice before and during COVID-19 Pandemics

Mother-to-child transmission(MTCT)of syphilis remains a leading cause of stillbirth and death among neonates in many developing countries.In 2007,World Health Orgernization launched the global elimination of MTCT(EMTCT)of syphilis.Given the high burden of congenital syphilis,China subsequently released the specific national EMTCT policies and programs to reduce MTCT of syphilis.The congenital syphilis incidence rate per 100,000 live births in China has markedly decreased from 69.9 in 2013 to 11.9 in 2019.However,due to the global pandemic of COVID-19,the current measures for eliminating MTCT of syphilis are greatly challenged.In this article,we summarize the strategies and measures for the EMTCT of syphilis in China in the past 20 years,the remarkable achievements by the policy support under the leadership of the government.In the context of COVID-19 pandemics,strengthening emergency response to the regional outbreaks of COVID-19,adopting safe,rapid,early and high-quality clinical care for 100%of pregnant women to receive prenatal syphilis testing services,ensuring the availability of Benzathine penicillin for the treatment,and strengthening the closed-loop management of pregnant women and newborns infected with syphilis are the key measures to determine the effectiveness of MTCT for syphilis.Lessons from China may be valuable for other countries that are planning to eliminate MTCT of syphilis.

Clinical characteristics of patients with COVID-19 presenting with gastrointestinal symptoms as initial symptoms: Retrospective case series

BACKGROUND A large number of pneumonia cases due to coronavirus disease 2019(COVID-19)have been first reported in China.Meanwhile,the virus is sweeping all around the world and has infected millions of people.Fever and pulmonary symptoms have been noticed as major and early signs of infection,whereas gastrointestinal symptoms were also observed in a significant portion of patients.The clinical investigation of disease onset was underestimated,especially due to the neglection of cases presenting with gastrointestinal symptoms.AIM To characterize the clinical features of coronavirus-infected patients with gastrointestinal symptoms as initial symptoms.METHODS This is a retrospective,single-center case series of the general consecutive hospitalized patients with confirmed COVID-19 at Wuhan Union Hospital from February 2,2020 to February 13,2020.According to their initial symptoms,these patients were classified into two groups.Patients in group one presented with pulmonary symptoms(PS)as initial symptoms,and group two presented with gastrointestinal symptoms(GS).Epidemiological,demographic,clinical,laboratory,and treatment data were collected for analysis.RESULTS Among the 50 patients recruited,no patient has been admitted to intensive care units,and no patient died during the study.The duration of hospitalization was longer in the GS group than in the PS group(12.13±2.44 vs 10.00±2.13,P<0.01).All of the 50 patients exhibited decreased lymphocytes.However,lymphocytes in the GS group were significantly lower compared to those in the PS group(0.94±0.06 vs 1.04±0.15,P<0.01).Procalcitonin and hs-CRP were both significantly higher in the GS group than in the PS group.Accordingly,the duration of viral shedding was significantly longer in the GS group compared to the PS group(10.22±1.93 vs 8.15±1.87,P<0.01).CONCLUSION COVID-19 patients presenting with gastrointestinal symptoms as initial symptoms need more days of viral shedding and hospitalization than the patients presenting with pulmonary symptoms.

Clinical characteristics,diagnosis,and treatment of COVID-19:A case report

BACKGROUND Since December 2019,many cases of pneumonia caused by novel coronavirus have been discovered in Wuhan,China,and such cases have spread nationwide quickly.At present,coronavirus disease 2019(COVID-19)is a worldwide pandemic.What are the clinical features of this disease?What is the clinical diagnosis and how should such patients be treated?As a clinician,mastery of the clinical characteristics,basic diagnosis,and treatment methods of COVID-19 are required to provide help to patients.CASE SUMMARY A 42-year-old male patient with a cough lasting 6 d without obvious cause,as well as fever and fatigue for 1 d,was admitted to Hankou Hospital on January 22,2020 and transferred to Huoshenshan Hospital on February 4.The main clinical symptoms were dry cough,fatigue,and fever.He was diagnosed with COVID-19.From the 4th d of admission,the patient’s condition gradually worsened,with increased respiratory rate and body temperature.Peripheral blood lymphocytes decreased progressively.On the 8th d of admission,the patient’s highest temperature was 40.7°C,and oxygen saturation was 83%despite high-flow oxygen inhalation.Chest computed tomography results showed that the virus progressed rapidly.The number of lesions significantly increased with expanded scope and increased density.The distribution of lesions advanced from peripheral to central.In addition to nasal catheter oxygen inhalation and symptomatic support,antiviral drugs were used throughout the treatment.On January 22,oseltamivir phosphate capsules were given orally(75 mg,twice daily)for 6 d.On January 24,three tablets of lopinavir and ritonavir were added orally(twice daily).After 6 d,this was changed to 0.2 g(two tablets)arbidol,taken orally(three times daily)for 5 d.During the severe stage,methylprednisolone was given(40 mg)once every 12 h,immunoglobulin(20 g)was administered by intravenous drip infusion once daily,and thymosin(1.6 mg)was injected subcutaneously once daily combined with immunotherapy.On February 2,symptoms decreased,various indicators improved,and pulmonary inflammation was obviously reduced.Throat swabs on February 4 and 9 were negative for novel coronavirus nucleic acid.After 19 d in the hospital,the patient was successfully treated and discharged.CONCLUSION COVID-19 in young adults can be successfully treated with active treatment.We report a typical case of COVID-19,analyze its clinical characteristics,summarize its clinical diagnosis and treatment experience,and provide a reference for clinical colleagues.

Epidemiological Characteristics of COVID-19 Confirmed Cases in Muscat Governorate, Sultanate of Oman

Introduction: The coronavirus disease 2019 (COVID-19) was declared as pandemic by WHO by March 11th. First case reported in Oman was on 24th February 2020 and later the country went through stages of epidemic progression. This study describes the sociodemographic and epidemiological characteristics of confirmed COVID-19 cases in Muscat governorate and related outcomes. Materials and Methods: This is a descriptive, exploratory analysis of all lab confirmed COVID 19 cases that were reported from 1st February to 31st May 2020. Data for the study was primarily extracted from notifications system established for surveillance (Tarassud). Secondary data sources were, contact listings and hospital medical records. Results: 11,648 initial cases of confirmed COVID-19 infections were included. The mean age was 35 years, 84.7% (N = 9862) were males, 25.9% (N = 3017) were Omanis, and 74.1% (N = 8631) were expatriates of which Indian origin were the majority (37%). Fever and cough were the most common presentations (46.3% and 29.5% respectively). Diabetes and hypertension were the most common comorbidities (4.9% and 4.6% respectively). Hospital admission was required for 7% (N = 811) of the total reported cases, out of them 171 cases (21%) were admitted to ICU, where 107 (13.2%) were ventilated. The case fatality rate (CFR) was 0.9%. 158 clusters containing 2949 contacts were identified from case records and categorised into 3 groups based on their exposure settings. The incubation period measured was 8 days (IQR 4.0 - 15.0) for workplace, 8 days (IQR 4 - 17) for dormitory and 4 days (IQR 2.0 - 7.0) for family groups. The secondary attack rate (SAR) estimated was 41.6% (95% CI: 0.34 - 0.48), 52% (95% CI: 0.40 - 0.63) and 33% (95% CI: 0.27 - 0.38) for workplace, dormitory and family groups, respectively. Conclusion: Results of this study, determine the transmission trend of COVID-19 in a country with high immigrant population. These findings could be utilised for further response planning in similar settings.

Epidemiology and Clinical Characteristics of the First 500 Positive Cases of COVID-19. A Multicenter Retrospective Study across the Najran Region of the Kingdom of Saudi Arabia (KSA)

Introduction: Coronavirus Disease 2019 (COVID-19) is a viral infection that was first reported in Wuhan, China on 31 December 2019. This study aimed to clarify the epidemiology and clinical characteristics of 500 first COVID-19 in the Najran region, Saudi Arabia. Material and Methods: A multi-center retrospective study design was employed to study the first 500 confirmed COVID-19 positive cases in Najran province, Kingdom of Saudi Arabia (KSA). Data were collected from 1 March 2020 until 1 July 2020 and provided by the Infection Prevention and Control (IPC) department from the hospitals. Included cases were confirmed using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Demographic, vital signs, symptoms, incubation period, travel or exposure history medical history, and comorbidities were collected. Logistic regression analysis was used to explore the association between potential risk factors associated with symptoms occurrence of COVID-19. Results: The median age of 500 COVID-19 patients was 31 years;333 (66.6%) males. A total of 34 (6.8%) were Healthcare Workers (HCWs). Out of the 500 patients, 180 (36%) had at least one comorbid disease. The most common symptoms on admission were fever 281 (56.2%), cough 266 (53.2%), shortness of breath 166 (33.2%), and malaise 113 (22.6%). Most of the patients presented with mild disease severity 310 (62%). Nationality, age, and Diabetes Miletus (DM) were independently and significantly associated with being symptomatic (P < 0.05). Compared to Saudi nationals, other nationality patients were most likely to have symptoms (β = 2.968, CI = 2.002 - 4.400, P = 0.0010). For every 1 year increase in age, the risk of being symptomatic increased by 5.8% (β = 1.045, CI = 1.033 - 1.058, P = 0.001). Compared with non-DM patients, DM patients had a 4.05 times higher risk (β = 4.05, CI = 2.188 - 7.507, P = 0.001) of getting symptoms. Conclusions: The study concluded that the majority of the COVID-19 patients were symptomatic or had mild disease severity. Age, nationality, and DM were the important risk factors in being symptomatic.

Awareness about transmission and preventive measures of COVID-19 from mother to child: A cross-sectional study among pregnant women

Objective:To study the knowledge,attitude,and practice of pregnant women regarding transmission and preventive measures of COVID-19 from mother to child and to determine the reasons for vaccine hesitancy.Methods:This observational cross-sectional knowledge,attitude,and practice study was conducted among pregnant women of any trimester,attending the antenatal care out-patient department of a tertiary care hospital in Lucknow from October 2020 to March 2021.All the participants were interviewed using a pretested semi-structured questionnaire for desired information.Reasons for vaccine hesitancy were also asked to assess their unwillingness to get vaccinated.Results:Totally 652 pregnant women were included and 91.3%were aware that COVID-19 spread through contact with an infected person and 85.3%knew that COVID-19 spread by respiratory droplets.Of pregnant women,95.7%perceived that social distancing and wearing a proper mask were effective ways to prevent SARS-CoV-2 infection and 96.8%of the pregnant women wore masks regularly when going out.Of pregnant women,79.0%were hesitant to get vaccinated.The most common reason was that COVID-19 vaccine can harm the developing fetus(77.5%)and was not very safe in pregnancy(75.0%).Conclusions:Of the pregnant women,22.92%have unsatisfactory knowledge regarding COVID-19,35.63%have negative attitude and 19.93%have poor practices,indicating that there are still gaps in awareness,and majority of them are unwilling to get vaccinated.Good awareness will help prevent the occurrence of future COVID-19 waves in India.

Dynamics of transmission of COVID-19 cases and household contacts:A prospective cohort study

Objective:To study the transmission dynamics of coronavirus disease 2019(COVID-19)among 101 confirmed cases and their 387 household contacts and to determine risk factors associated with secondary attack among the household contacts.Methods:A prospective cohort study was conducted from January 1st 2021 to February 28th 2021,among 101 SARS-CoV-2 cases and 387 household contacts who were followed up for 14 days from the last day of contact with the index case of COVID-19.The dynamics of disease transmission was estimated,and factors affecting transmission risk were analyzed.Besides,the association between various factors and household secondary attack rate was determined.Results:The median incubation period was found to be 5 days,and the observed reproductive number(R)was found to be 1.63(95%CI:1.28-1.98).The mean household secondary attack rate was 40.7%.Contacts with comorbidities like diabetes mellitus,hypertension,dyslipidemia,and hypothyroidism had significantly higher attack rates(P<0.05).Conclusions:As new variants of SARS-CoV-2 emerges,it is crucial to know the trasmission dynamics.This study shows a high secondary attack rate of COVID-19 among household contacts that must be closely monitored.

Epidemiological and clinical characteristics of fifty-six cases of COVID-19 in Liaoning Province, China

BACKGROUND Pneumonia of uncertain cause has been reported in Wuhan,China since the beginning of early December 2019.In early January 2020,a novel strain ofβ-coronavirus was identified by the Chinese Center for Disease Control and Prevention from the pharyngeal swab specimens of patients,which was recently named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).There is evidence of human-to-human transmission and familial cluster outbreak of SARSCoV-2 infection.The World Health Organization(WHO)recently declared the SARS-CoV-2 epidemic a global health emergency.As of February 17,2020,71329 laboratory-confirmed cases(in 25 countries,including the United States and Germany)have been reported globally.Other than its rapid transmission,the epidemiological and clinical characteristics of coronavirus disease 2019(COVID-19)remain unclear.In December 2019,coronavirus disease(named COVID-19 by the WHO)associated with the SARS-CoV-2 emerged in Wuhan,China and spread quickly across the country.AIM To analyze the epidemiological and clinical characteristics of confirmed cases of this disease in Liaoning province,a Chinese region about 1800 km north of Wuhan.METHODS The clinical data of 56 laboratory-confirmed COVID-19 cases due to 2019-nCoV infection were analyzed.The cases originated from eight cities in Liaoning province.RESULTS The median age of the patients was 45 years,and 57.1%of them were male.No patient had been in direct contact with wild animals.Among them,23 patients(41.1%)had resided in or traveled to Wuhan,27 cases(48.2%)had been in contact with confirmed COVID-19 patients,5 cases(8.9%)had been in contact with confirmed patients with a contact history to COVID-19 patients,and 1 case(1.8%)had no apparent history of exposure.Fever(75.0%)and cough(60.7%)were the most common symptoms.The typical manifestations in lung computed tomography(CT)included ground-glass opacity and patchy shadows,with 67.8%of them being bilateral.Among the patients in the cohort,78.6%showed reduction in their lymphocyte counts,57.1%showed increases in their C-reactive protein levels,and 50.0%showed decreases in their blood albumin levels.Eleven patients(19.6%)were admitted to intensive care unit,2 patients(3.5%)progressed to acute respiratory distress syndrome,4 patients(7.1%)were equipped with non-invasive mechanical ventilation,and 1 patient(1.8)received extracorporeal membrane oxygenation support.There were 5 mild cases(5/56,8.9%),40 moderate cases(40/56,71.4%),10 severe cases(10/56,17.9%),and 1 critical case(1/56,1.8%).No deaths were reported.CONCLUSION SARS-CoV-2 can be transmitted among humans.Most COVID-19 patients show symptoms of fever,cough,lymphocyte reduction,and typical lung CT manifestations.Most are moderate cases.The seriousness of the disease(as indicated by blood oxygen saturation,respiratory rate,oxygenation index,blood lymphocyte count,and lesions shown in lung CT)is related to history of living in or traveling to Wuhan,underlying diseases,admittance to intensive care unit,and mechanical ventilation.

Clinical Characteristics and Outcomes of Severe or Critical COVID-19 Patients Presenting No Respiratory Symptoms or Fever at Onset

It is difficult to identify suspected cases of atypical patients with coronavirus disease 2019(COVID-19),and data on severe or critical patients are scanty.This retrospective study presents the clinical,laboratory,and radiological profiles,treatments,and outcomes of atypical COVID-19 patients without respiratory symptoms or fever at onset.The study examined ten atypical patients out of 909 severe or critical patients diagnosed with COVID-19 in Wuhan Union Hospital West Campus between 25 January 2020 and 10 February 2020.Data were obtained from the electronic medical records of severe or critical patients without respiratory symptoms or fever at onset.Outcomes were followed up to discharge or death.Among 943 COVID-19 patients,909(96.4%)were severe or critical type.Of the severe or critical patients,ten(1.1%)presented without respiratory symptoms or fever at admission.The median age of the ten participants was 63 years(interquartile range(IQR):57–72),and seven participants were men.The median time from symptom onset to admission was 14 d(IQR:7–20).Eight of the ten patients had chronic diseases.The patients had fatigue(n=5),headache or dizziness(n=4),diarrhea(n=5),anorexia(n=3),nausea or vomiting(n=3),and eye discomfort(n=1).Four patients were found to have lymphopenia.Imaging examination revealed that nine patients had bilateral pneumonia and one had unilateral pneumonia.Eventually,two patients died and eight were discharged.In the discharged patients,the median time from admission to discharge lasted 24 d(IQR:13–43).In summary,some severe or critical COVID-19 patients were found to have no respiratory symptoms or fever at onset.All such atypical cases should be identified and quarantined as early as possible,since they tend to have a prolonged hospital stay or fatal outcomes.Chest computed tomography(CT)scan and nucleic acid detection should be performed immediately on close contacts of COVID-19 patients to screen out those with atypical infections,even if the contacts present without respiratory symptoms or fever at onset.

Prediction of COVID-19 Transmission in the United States Using Google Search Trends

Accurate forecasting of emerging infectious diseases can guide public health officials in making appropriate decisions related to the allocation of public health resources.Due to the exponential spread of the COVID-19 infection worldwide,several computational models for forecasting the transmission and mortality rates of COVID-19 have been proposed in the literature.To accelerate scientific and public health insights into the spread and impact of COVID-19,Google released the Google COVID-19 search trends symptoms open-access dataset.Our objective is to develop 7 and 14-day-ahead forecasting models of COVID-19 transmission and mortality in the US using the Google search trends for COVID-19 related symptoms.Specifically,we propose a stacked long short-term memory(SLSTM)architecture for predicting COVID-19 confirmed and death cases using historical time series data combined with auxiliary time series data from the Google COVID-19 search trends symptoms dataset.Considering the SLSTM networks trained using historical data only as the base models,our base models for 7 and 14-day-ahead forecasting of COVID cases had the mean absolute percentage error(MAPE)values of 6.6%and 8.8%,respectively.On the other side,our proposed models had improved MAPE values of 3.2%and 5.6%,respectively.For 7 and 14-day-ahead forecasting of COVID-19 deaths,the MAPE values of the base models were 4.8%and 11.4%,while the improved MAPE values of our proposed models were 4.7%and 7.8%,respectively.We found that the Google search trends for“pneumonia,”“shortness of breath,”and“fever”are the most informative search trends for predicting COVID-19 transmission.We also found that the search trends for“hypoxia”and“fever”were the most informative trends for forecasting COVID-19 mortality.

Epidemiological characteristics of COVID-19 cases in a hotel Fangcang shelter hospital in Sanya

Objective:To analyze the epidemiological characteristics of COVID-19 cases(Omicron variant BA5.1.3)in a hotel Fangcang shelter hospital in Sanya,Hainan Province,and provide basis for optimizing epidemic prevention and control strategies.Methods:The epidemiological data of COVID-19 cases admitted to a hotel Fangcang shelter hospital in Sanya from August 10 to August 30 in 2022 were collected for descriptive epidemiological analysis.Results:By August 30,703 cases of COVID-19 had been treated in the hotel Fangcang shelter hospital.The epidemiological characteristics analysis showed that 328 cases were male,accounting for 46.7%,and 375 cases were female,accounting for 53.3%.The ratio of male to female was 0.87:1.The age range was 8 months to 85 years old,with a median of 37(20,49)years old.The majority of people aged 31-59 years old,accounting for 51.4%.Asymptomatic infection accounted for 39.8%,and mild infection accounted for 60.2%,the main clinical symptoms were cough 24.8%(105/423),fever 18.7%(79/423).8.8%of the infected people had a history of chronic basic diseases,and hypertension and diabetes were the most common.There were 416 infected patients discharged from hospital,and the median total hospital stay was 14(10,15)days.The proportion of people who did not receive COVID-19 vaccine was 10.1%,the proportion of people who completed one,two and three vaccination was 5.0%,36.3%and 48.6%respectively,and the proportion of people who completed two and three vaccinations among people ≥60 years old was only 10.1%and 8.8%.Conclusion:This strain was the novel coronavirus variant BA5.1.3,which was reported for the first time in China.It was more infectious and insidious,and generally susceptible to people of all ages.Therefore,it is necessary to strengthen personal prevention and control,and did a good job of external anti input and internal anti diffusion,and strengthen nucleic acid detection to realize timely detection and early treatment,and strengthen COVID-19 vaccination,to improve vaccination rate and reduce infection rate.

Epidemiological characteristics of 168 cases of COVID-19 in Hainan Island, tropical China: A descriptive study

Objective:To understand the epidemic characters of COVID-19 epidemic in Hainan province of tropical China and provid evidences for the prevention and control of the epidemic.Methods:Data on the COVID-19 epidemic collected from Health Commission of Hainan Province were analyzed by using the methods of retrospective descriptive epidemiology.Results:From January 22nd to February 21st,2020,COVID-19 was diagnosed in 168 confirmed cases(including 8 severe cases)in Hainan Province with the temporary fatality rate of 2.38%of 4 deaths,and 96 cases discharged from hospital,with the cure rate of 57.14%.The cases were distributed in altogether 15 cities and counties in Hainan Province,among which 121 cases were distributed in Sanya,Haikou,Danzhou and Wanning,accounting for 72.02%of the total number of cases.Cases in Sanya City were mainly found in Tianya district and Jiyang district,accounting for 69.81%of the total number of cases in Sanya.Cases in Haikou City were mainly found in Qiongshan district and Xiuying district,accounting for 72.5%of the total number of cases in Haikou.Among the patients,there were 81 males and 87 females,with a male-to-female ratio of 1.1;the youngest age was 3 months,the oldest was 79 years old,80%of the patients were in the age group of 30 to 69 years old,and the number of children and adolescents under 20 years old were relatively low.Conclusion:The daily number of new confirmed cases showed a gradual downward trend in Hainan province,and the epidemic situation was in transition from imported to local renewal,mainly in close contact between family members.With the increase of personnel mobility such as the resumption of work by enterprises and the return of migrant workers to the island,there is a risk of agglomeration epidemic.Prevention and control work in urban and rural areas should take a two-pronged approach.Amid preventing imported cases,more proactive measures should be taken to prevent and control the spread of local cases.

COVID-19 in the endoscopy unit:How likely is transmission of infection?Results from an international,multicenter study

BACKGROUND Coronavirus disease 2019(COVID-19)significantly affected endoscopy practice,as gastrointestinal endoscopy is considered a risky procedure for transmission of infection to patients and personnel of endoscopy units(PEU).AIM To assess the impact of COVID-19 on endoscopy during the first European lockdown(March-May 2020).METHODS Patients undergoing endoscopy in nine endoscopy units across six European countries during the period of the first European lockdown for COVID-19(March-May 2020)were included.Prior to the endoscopy procedure,participants were stratified as low-or high-risk for potential COVID-19 infection according to the European Society of Gastrointestinal Endoscopy(ESGE)and the European Society of Gastroenterology and Endoscopy Nurses and Associates(ESGENA)joint statement,and contacted 7-14 d later to assess COVID-19 infection status.PEU were questioned regarding COVID-19 symptoms and/or infection via questionnaire,while information regarding hospitalizations,intensive care unitadmissions and COVID-19-related deaths were collected.The number of weekly endoscopies at each center during the lockdown period was also recorded.RESULTS A total of 1267 endoscopies were performed in 1222 individuals across nine European endoscopy departments in six countries.Eighty-seven(7%)were excluded because of initial positive testing.Of the 1135 pre-endoscopy low risk or polymerase chain reaction negative for COVID-19,254(22.4%)were tested post endoscopy and 8 were eventually found positive,resulting in an infection rate of 0.7%[95%CI:0.2-0.12].The majority(6 of the 8 patients,75%)had undergone esophagogastroduodenoscopy.Of the 163 PEU,5[3%;(95%CI:0.4-5.7)]tested positive during the study period.A decrease of 68.7%(95%CI:64.8-72.7)in the number of weekly endoscopies was recorded in all centers after March 2020.All centers implemented appropriate personal protective measures(PPM)from the initial phases of the lockdown.CONCLUSION COVID-19 transmission in endoscopy units is highly unlikely in a lockdown setting,provided endoscopies are restricted to emergency cases and PPM are implemented.

Real-Time COVID-19 Forecasting for Four States of India Using a Regression Transmission Model

Introduction: More than a million people are reported to have been infected with COVID in India, since the beginning of the pandemic. However, the epidemic is not the same across the country. Though there are state-level variations rapidly changing disease dynamics and the response has created uncertainty towards appropriate use of models to project for the future. Method: This paper aims at using a validated semi-mechanistic stochastic model to generate short term forecasts. This analysis used data available at the respective state government bulletins for four states. The analysis used a simplified transmission model using Markov Chain Monte Carlo simulation with Metropolis-Hastings updating. Results: Two weeks were used to compare the results with the actual data. The forecasted results are well within the 25th and 75th percentile of the actual cases reported by the respective states. The results indicate a reliable method for a real-time short term forecasting of COVID-19 cases. The 1st week projected interquartile range and actual;reported cases for the state of Kerala, Tamil Nadu, Andhra Pradesh and Odisha were (1064 - 2532) 2234, (17,503 - 50,125) 27,214, (5225 - 11,003) 9563, (2559 - 4461) 3925, respectively. Similarly, the 2nd week projected interquartile range and actual;reported cases were (1055 - 7803) 4221, (18,298 - 73,952) 31,488, (4705 - 23,224) 13,357, (2701 - 9037) 4175 respectively. Conclusion: This real-time forecast can be used as an early warning tool for projecting the changes in the epidemic in the near future triggering proactive management steps.