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1.
N Z Med J ; 134(1529): 26-38, 2021 02 05.
Article in English | MEDLINE | ID: covidwho-1080082

ABSTRACT

AIM: We aimed to estimate the risk of COVID-19 outbreaks in a COVID-19-free destination country (New Zealand) associated with shore leave by merchant ship crews who were infected prior to their departure or on their ship. METHODS: We used a stochastic version of the SEIR model CovidSIM v1.1 designed specifically for COVID-19. It was populated with parameters for SARS-CoV-2 transmission, shipping characteristics and plausible control measures. RESULTS: When no control interventions were in place, we estimated that an outbreak of COVID-19 in New Zealand would occur after a median time of 23 days (assuming a global average for source country incidence of 2.66 new infections per 1,000 population per week, crews of 20 with a voyage length of 10 days and 1 day of shore leave per crew member both in New Zealand and abroad, and 108 port visits by international merchant ships per week). For this example, the uncertainty around when outbreaks occur is wide (an outbreak occurs with 95% probability between 1 and 124 days). The combination of PCR testing on arrival, self-reporting of symptoms with contact tracing and mask use during shore leave increased this median time to 1.0 year (14 days to 5.4 years, or a 49% probability within a year). Scenario analyses found that onboard infection chains could persist for well over 4 weeks, even with crews of only 5 members. CONCLUSION: This modelling work suggests that the introduction of SARS-CoV-2 through shore leave from international shipping crews is likely, even after long voyages. But the risk can be substantially mitigated by control measures such as PCR testing and mask use.


Subject(s)
Communicable Diseases, Imported/prevention & control , Disease Transmission, Infectious , Naval Medicine , Quarantine/methods , Ships , /diagnosis , /prevention & control , /methods , Communicable Disease Control/instrumentation , Communicable Disease Control/methods , Computer Simulation , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Humans , Masks , Naval Medicine/methods , Naval Medicine/statistics & numerical data , New Zealand/epidemiology
2.
N Z Med J ; 134(1529): 10-25, 2021 02 05.
Article in English | MEDLINE | ID: covidwho-1080064

ABSTRACT

AIMS: We developed a model, updated daily, to estimate undetected COVID-19 infections exiting quarantine following selectively opening New Zealand's borders to travellers from low-risk countries. METHODS: The prevalence of infectious COVID-19 cases by country was multiplied by expected monthly passenger volumes to predict the rate of arrivals. The rate of undetected infections entering the border following screening and quarantine was estimated. Level 1, Level 2 and Level 3 countries were defined as those with an active COVID-19 prevalence of up to 1/105, 10/105 and 100/105, respectively. RESULTS: With 65,272 travellers per month, the number of undetected COVID-19 infections exiting quarantine is 1 every 45, 15 and 31 months for Level 1, Level 2 and Level 3 countries, respectively. The overall rate of undetected active COVID-19 infections exiting quarantine is expected to increase from the current 0.40 to 0.50 per month, or an increase of one extra infection every 10 months. CONCLUSIONS: Loosening border restrictions results in a small increase in the rate of undetected COVID-19 infections exiting quarantine, which increases from the current baseline by one infection every 10 months. This information may be useful in guiding decision-making on selectively opening of borders in the COVID-19 era.


Subject(s)
Communicable Disease Control , Communicable Diseases, Imported , Disease Transmission, Infectious , International Health Regulations , Quarantine , /epidemiology , /transmission , Communicable Disease Control/methods , Communicable Disease Control/organization & administration , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Forecasting , Global Health , Humans , International Health Regulations/organization & administration , International Health Regulations/trends , New Zealand/epidemiology , Prevalence , Public Policy , Quarantine/organization & administration , Quarantine/statistics & numerical data , Travel/legislation & jurisprudence , Travel/statistics & numerical data
3.
BMC Med Res Methodol ; 21(1): 30, 2021 02 10.
Article in English | MEDLINE | ID: covidwho-1079210

ABSTRACT

BACKGROUND: In infectious disease transmission dynamics, the high heterogeneity in individual infectiousness indicates that few index cases generate large numbers of secondary cases, which is commonly known as superspreading events. The heterogeneity in transmission can be measured by describing the distribution of the number of secondary cases as a negative binomial (NB) distribution with dispersion parameter, k. However, such inference framework usually neglects the under-ascertainment of sporadic cases, which are those without known epidemiological link and considered as independent clusters of size one, and this may potentially bias the estimates. METHODS: In this study, we adopt a zero-truncated likelihood-based framework to estimate k. We evaluate the estimation performance by using stochastic simulations, and compare it with the baseline non-truncated version. We exemplify the analytical framework with three contact tracing datasets of COVID-19. RESULTS: We demonstrate that the estimation bias exists when the under-ascertainment of index cases with 0 secondary case occurs, and the zero-truncated inference overcomes this problem and yields a less biased estimator of k. We find that the k of COVID-19 is inferred at 0.32 (95%CI: 0.15, 0.64), which appears slightly smaller than many previous estimates. We provide the simulation codes applying the inference framework in this study. CONCLUSIONS: The zero-truncated framework is recommended for less biased transmission heterogeneity estimates. These findings highlight the importance of individual-specific case management strategies to mitigate COVID-19 pandemic by lowering the transmission risks of potential super-spreaders with priority.


Subject(s)
Binomial Distribution , /transmission , Computer Simulation , Disease Transmission, Infectious/statistics & numerical data , Humans , Infectious Disease Medicine/statistics & numerical data , Likelihood Functions , Pandemics , Population Surveillance , Selection Bias
4.
Medicine (Baltimore) ; 100(5): e23925, 2021 Feb 05.
Article in English | MEDLINE | ID: covidwho-1062935

ABSTRACT

ABSTRACT: The World Health Organization (WHO) classified the spread of COVID-19 (Coronavirus Disease 2019) as a global pandemic in March. Scholars predict that the pandemic will continue into the coming winter and will become a seasonal epidemic in the following year. Therefore, the identification of effective control measures becomes extremely important. Although many reports have been published since the COVID-19 outbreak, no studies have identified the relative effectiveness of a combination of control measures implemented in Wuhan and other areas in China. To this end, a retrospective analysis by the collection and modeling of an unprecedented number of epidemiology records in China of the early stage of the outbreaks can be valuable.In this study, we developed a new dynamic model to describe the spread of COVID-19 and to quantify the effectiveness of control measures. The transmission rate, daily close contacts, and the average time from onset to isolation were identified as crucial factors in viral spreading. Moreover, the capacity of a local health-care system is identified as a threshold to control an outbreak in its early stage. We took these factors as controlling parameters in our model. The parameters are estimated based on epidemiological reports from national and local Center for Disease Control (CDCs).A retrospective simulation showed the effectiveness of combinations of 4 major control measures implemented in Wuhan: hospital isolation, social distancing, self-protection by wearing masks, and extensive medical testing. Further analysis indicated critical intervention conditions and times required to control an outbreak in the early stage. Our simulations showed that South Korea has kept the spread of COVID-19 at a low level through extensive medical testing. Furthermore, a predictive simulation for Italy indicated that Italy would contain the outbreak in late May under strict social distancing.In our general analysis, no single measure could contain a COVID-19 outbreak once a health-care system is overloaded. Extensive medical testing could keep viral spreading at a low level. Wearing masks functions as favorably as social distancing but with much lower socioeconomic costs.


Subject(s)
Communicable Disease Control , Hospitalization/statistics & numerical data , Outcome Assessment, Health Care/methods , /isolation & purification , /economics , /prevention & control , China/epidemiology , Communicable Disease Control/methods , Communicable Disease Control/organization & administration , Communicable Disease Control/standards , Contact Tracing/statistics & numerical data , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Humans , Models, Theoretical , Mortality , Systems Analysis , Time-to-Treatment/statistics & numerical data
5.
Emerg Infect Dis ; 27(2): 586-589, 2021 02.
Article in English | MEDLINE | ID: covidwho-1048934

ABSTRACT

We conducted a cross-sectional survey to estimate the seroprevalence of IgG against severe acute respiratory syndrome coronavirus 2 in Chennai, India. Among 12,405 serum samples tested, weighted seroprevalence was 18.4% (95% CI 14.8%-22.6%). These findings indicate most of the population of Chennai is still susceptible to this virus.


Subject(s)
Antibodies, Viral/blood , /epidemiology , Disease Transmission, Infectious/statistics & numerical data , /immunology , Adolescent , Adult , Aged , Antibodies, Viral/immunology , /transmission , Child , Cluster Analysis , Cross-Sectional Studies , Female , Humans , India/epidemiology , Male , Middle Aged , Seroepidemiologic Studies , Young Adult
6.
Emerg Infect Dis ; 27(2): 612-615, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-1048930

ABSTRACT

We report an epidemiologic analysis of 4,210 cases of infection with severe acute respiratory syndrome coronavirus 2 and genetic analysis of 313 new near-complete virus genomes in Panama during March 9-April 16, 2020. Although containment measures reduced R0 and Rt, they did not interrupt virus spread in the country.


Subject(s)
/statistics & numerical data , Disease Transmission, Infectious/statistics & numerical data , Genome, Viral/genetics , Population Surveillance , /genetics , Adolescent , Adult , Aged , /epidemiology , Female , Humans , Male , Middle Aged , Panama/epidemiology , Phylogeny , Time Factors , Young Adult
7.
Emerg Infect Dis ; 27(2): 452-462, 2021 02.
Article in English | MEDLINE | ID: covidwho-1048927

ABSTRACT

Greece imposed a nationwide lockdown in March 2020 to mitigate transmission of severe acute respiratory syndrome coronavirus 2 during the first epidemic wave. We conducted a survey on age-specific social contact patterns to assess effects of physical distancing measures and used a susceptible-exposed-infectious-recovered model to simulate the epidemic. Because multiple distancing measures were implemented simultaneously, we assessed their overall effects and the contribution of each measure. Before measures were implemented, the estimated basic reproduction number (R0) was 2.38 (95% CI 2.01-2.80). During lockdown, daily contacts decreased by 86.9% and R0 decreased by 81.0% (95% credible interval [CrI] 71.8%-86.0%); each distancing measure decreased R0 by 10%-24%. By April 26, the attack rate in Greece was 0.12% (95% CrI 0.06%-0.26%), one of the lowest in Europe, and the infection fatality ratio was 1.12% (95% CrI 0.55%-2.31%). Multiple social distancing measures contained the first epidemic wave in Greece.


Subject(s)
/epidemiology , Disease Transmission, Infectious/statistics & numerical data , Models, Statistical , Quarantine/statistics & numerical data , Adolescent , Adult , Aged , /transmission , Child , Child, Preschool , Disease Transmission, Infectious/prevention & control , Female , Greece/epidemiology , Humans , Incidence , Infant , Infant, Newborn , Male , Middle Aged , Quarantine/legislation & jurisprudence , Young Adult
8.
Emerg Infect Dis ; 27(2): 582-585, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-1048923

ABSTRACT

We estimated the generation interval distribution for coronavirus disease on the basis of serial intervals of observed infector-infectee pairs from established clusters in Singapore. The short mean generation interval and consequent high prevalence of presymptomatic transmission requires public health control measures to be responsive to these characteristics of the epidemic.


Subject(s)
/transmission , Disease Transmission, Infectious/statistics & numerical data , Models, Statistical , Symptom Assessment/statistics & numerical data , Time Factors , /epidemiology , Cluster Analysis , Cross-Sectional Studies , Humans , Infectious Disease Incubation Period , Singapore/epidemiology
9.
Sci Rep ; 11(1): 1936, 2021 01 21.
Article in English | MEDLINE | ID: covidwho-1043486

ABSTRACT

Exploiting the SIQR model for COVID-19, I show that the wavy infection curve in Japan is the result of fluctuation of policy on isolation measure imposed by the government and obeyed by citizens. Assuming the infection coefficient be a two-valued function of the number of daily confirmed new cases, I show that when the removal rate of infected individuals is between these two values, the wavy infection curve is self-organized. On the basis of the infection curve, I classify the outbreak of COVID-19 into five types and show that these differences can be related to the relative magnitude of the transmission coefficient and the quarantine rate of infected individuals.


Subject(s)
/epidemiology , Disease Transmission, Infectious/statistics & numerical data , Quarantine/methods , /prevention & control , /virology , Humans , Japan/epidemiology , Models, Theoretical , Quarantine/trends , /isolation & purification
10.
J Glob Health ; 10(2): 021104, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-1032535

ABSTRACT

Background: It is of paramount importance to understand the transmission of SARS-CoV-2 in schools, which could support the decision-making about educational facilities closure or re-opening with effective prevention and control measures in place. Methods: We conducted a systematic review and meta-analysis to investigate the extent of SARS-CoV-2 transmission in schools. We performed risk of bias evaluation of all included studies using the Newcastle-Ottawa Scale (NOS). Results: 2178 articles were retrieved and 11 studies were included. Five cohort studies reported a combined 22 student and 21 staff index cases that exposed 3345 contacts with 18 transmissions (overall infection attack rate (IAR): 0.08%, 95% confidence interval (CI) = 0.00%-0.86%). IARs for students and school staff were 0.15% (95% CI = 0.00%-0.93%) and 0.70% (95% CI = 0.00%-3.56%) respectively. Six cross-sectional studies reported 639 SARS-CoV-2 positive cases in 6682 study participants tested [overall SARS-CoV-2 positivity rate: 8.00% (95% CI = 2.17%-16.95%). SARS-CoV-2 positivity rate was estimated to be 8.74% (95% CI = 2.34%-18.53%) among students, compared to 13.68% (95% CI = 1.68%-33.89%) among school staff. Gender differences were not found for secondary infection (OR = 1.44, 95% CI = 0.50-4.14, P = 0.49) and SARS-CoV-2 positivity (OR = 0.90, 95% CI = 0.72-1.13, P = 0.36) in schools. Fever, cough, dyspnea, ageusia, anosmia, rhinitis, sore throat, headache, myalgia, asthenia, and diarrhoea were all associated with the detection of SARS-CoV-2 antibodies (based on two studies). Overall, study quality was judged to be poor with risk of performance and attrition bias, limiting the confidence in the results. Conclusions: There is limited high-quality evidence available to quantify the extent of SARS-CoV-2 transmission in schools or to compare it to community transmission. Emerging evidence suggests lower IAR and SARS-CoV-2 positivity rate in students compared to school staff. Future prospective and adequately controlled cohort studies are necessary to confirm this finding.


Subject(s)
/transmission , Disease Transmission, Infectious/statistics & numerical data , Schools/statistics & numerical data , Students/statistics & numerical data , Adolescent , Child , Cross-Sectional Studies , Female , Humans , Male
12.
PLoS One ; 16(1): e0241190, 2021.
Article in English | MEDLINE | ID: covidwho-1013205

ABSTRACT

Multiple national and international trends and drivers are radically changing what biological security means for the United Kingdom (UK). New technologies present novel opportunities and challenges, and globalisation has created new pathways and increased the speed, volume and routes by which organisms can spread. The UK Biological Security Strategy (2018) acknowledges the importance of research on biological security in the UK. Given the breadth of potential research, a targeted agenda identifying the questions most critical to effective and coordinated progress in different disciplines of biological security is required. We used expert elicitation to generate 80 policy-relevant research questions considered by participants to have the greatest impact on UK biological security. Drawing on a collaboratively-developed set of 450 questions, proposed by 41 experts from academia, industry and the UK government (consulting 168 additional experts) we subdivided the final 80 questions into six categories: bioengineering; communication and behaviour; disease threats (including pandemics); governance and policy; invasive alien species; and securing biological materials and securing against misuse. Initially, the questions were ranked through a voting process and then reduced and refined to 80 during a one-day workshop with 35 participants from a variety of disciplines. Consistently emerging themes included: the nature of current and potential biological security threats, the efficacy of existing management actions, and the most appropriate future options. The resulting questions offer a research agenda for biological security in the UK that can assist the targeting of research resources and inform the implementation of the UK Biological Security Strategy. These questions include research that could aid with the mitigation of Covid-19, and preparation for the next pandemic. We hope that our structured and rigorous approach to creating a biological security research agenda will be replicated in other countries and regions. The world, not just the UK, is in need of a thoughtful approach to directing biological security research to tackle the emerging issues.


Subject(s)
Pandemics/prevention & control , Security Measures/trends , Bioterrorism/prevention & control , Clinical Governance/trends , Communication , Disease Transmission, Infectious/prevention & control , Disease Transmission, Infectious/statistics & numerical data , Humans , Pandemics/statistics & numerical data , Policy , Security Measures/statistics & numerical data , Surveys and Questionnaires , United Kingdom/epidemiology
13.
PLoS One ; 16(1): e0244983, 2021.
Article in English | MEDLINE | ID: covidwho-1007112

ABSTRACT

Here we look into the spread of aerosols indoors that may potentially carry viruses. Many viruses, including the novel SARS-CoV-2, are known to spread via airborne and air-dust pathways. From the literature data and our research on the propagation of fine aerosols, we simulate herein the carryover of viral aerosols in indoor air. We demonstrate that a lot of fine droplets released from an infected person's coughing, sneezing, or talking propagate very fast and for large distances indoors, as well as bend around obstacles, lift up and down over staircases, and so on. This study suggests equations to evaluate the concentration of those droplets, depending on time and distance from the source of infection. Estimates are given for the safe distance to the source of infection, and available methods for neutralizing viral aerosols indoors are considered.


Subject(s)
/transmission , Disease Transmission, Infectious/prevention & control , Aerosols/analysis , Air Microbiology , Air Pollution, Indoor/analysis , /virology , Cough , Disease Transmission, Infectious/statistics & numerical data , Dust , Humans , Models, Theoretical , Sneezing/physiology , Virus Diseases/prevention & control
14.
Emerg Infect Dis ; 27(2): 421-429, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-1006452

ABSTRACT

To assess transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a detention facility experiencing a coronavirus disease outbreak and evaluate testing strategies, we conducted a prospective cohort investigation in a facility in Louisiana, USA. We conducted SARS-CoV-2 testing for detained persons in 6 quarantined dormitories at various time points. Of 143 persons, 53 were positive at the initial test, and an additional 58 persons were positive at later time points (cumulative incidence 78%). In 1 dormitory, all 45 detained persons initially were negative; 18 days later, 40 (89%) were positive. Among persons who were SARS-CoV-2 positive, 47% (52/111) were asymptomatic at the time of specimen collection; 14 had replication-competent virus isolated. Serial SARS-CoV-2 testing might help interrupt transmission through medical isolation and quarantine. Testing in correctional and detention facilities will be most effective when initiated early in an outbreak, inclusive of all exposed persons, and paired with infection prevention and control.


Subject(s)
/statistics & numerical data , Disease Outbreaks/statistics & numerical data , Disease Transmission, Infectious/statistics & numerical data , /isolation & purification , Adult , /transmission , Female , Humans , Incidence , Louisiana/epidemiology , Male , Prisons , Prospective Studies
15.
Ann Acad Med Singap ; 49(11): 857-869, 2020 11.
Article in English | MEDLINE | ID: covidwho-1001259

ABSTRACT

INTRODUCTION: Pregnant women are reported to be at increased risk of severe coronavirus disease 2019 (COVID-19) due to underlying immunosuppression during pregnancy. However, the clinical course of COVID-19 in pregnancy and risk of vertical and horizontal transmission remain relatively unknown. We aim to describe and evaluate outcomes in pregnant women with COVID-19 in Singapore. METHODS: Prospective observational study of 16 pregnant patients admitted for COVID-19 to 4 tertiary hospitals in Singapore. Outcomes included severe disease, pregnancy loss, and vertical and horizontal transmission. RESULTS: Of the 16 patients, 37.5%, 43.8% and 18.7% were infected in the first, second and third trimesters, respectively. Two gravidas aged ≥35 years (12.5%) developed severe pneumonia; one patient (body mass index 32.9kg/m2) required transfer to intensive care. The median duration of acute infection was 19 days; one patient remained reverse transcription polymerase chain reaction (RT-PCR) positive >11 weeks from diagnosis. There were no maternal mortalities. Five pregnancies produced term live-births while 2 spontaneous miscarriages occurred at 11 and 23 weeks. RT-PCR of breast milk and maternal and neonatal samples taken at birth were negative; placenta and cord histology showed non-specific inflammation; and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific immunoglobulins were elevated in paired maternal and umbilical cord blood (n=5). CONCLUSION: The majority of COVID-19 infected pregnant women had mild disease and only 2 women with risk factors (obesity, older age) had severe infection; this represents a slightly higher incidence than observed in age-matched non-pregnant women. Among the women who delivered, there was no definitive evidence of mother-to-child transmission via breast milk or placenta.


Subject(s)
/epidemiology , Pregnancy Complications, Infectious/epidemiology , Pregnancy Outcome/epidemiology , Abortion, Spontaneous/epidemiology , Adult , /transmission , Cohort Studies , Disease Transmission, Infectious/statistics & numerical data , Female , Fetal Blood/immunology , Humans , Infectious Disease Transmission, Vertical/statistics & numerical data , Live Birth/epidemiology , Maternal Age , Milk, Human/chemistry , Milk, Human/virology , Obesity, Maternal/epidemiology , Placenta/pathology , Pregnancy , Pregnancy Complications, Infectious/physiopathology , Pregnancy Trimester, First , Pregnancy Trimester, Second , Prospective Studies , RNA, Viral/analysis , Risk Factors , Severity of Illness Index , Singapore/epidemiology , Umbilical Cord/pathology , Young Adult
16.
Prev Med ; 143: 106385, 2021 02.
Article in English | MEDLINE | ID: covidwho-997625

ABSTRACT

The global outbreak of the coronavirus disease 2019 (COVID-19) in 2020 has been an international public health threat. Early strong social distancing efforts is needed to stop transmission of the virus. The purpose of the present study is to identify individual and environmental factors related to individuals' compliance with the recommended social distancing, as well as the moderating role of social media in influencing individuals' implementation of social distancing. A total of 2130 Chinese adults were surveyed in March 2020 during the COVID-19 pandemic. Logistic regression analyses were performed to ascertain the predictors of social distancing. Overall, the majority of respondents (95.6%) reported compliance with social distancing. Women were more likely to practice social distancing compared to men (odds ratio [OR] = 3.12, 95% confidence interval [CI] = 1.93-5.02). Psychological distress, depressive symptoms, and social media were significant predictors of social distancing after controlling for other individual and environmental factors. Social media moderated the effects of psychological distress on social distancing (OR = 0.96, 95% CI = 0.94-0.99). Findings from the study indicates that mental health status and social media are influential factors of social distancing, which have significant implications in enhancing the effectiveness of prevention strategies to contain the spread of COVID-19.


Subject(s)
Asian Continental Ancestry Group/psychology , /prevention & control , Disease Outbreaks/prevention & control , Disease Transmission, Infectious/prevention & control , Pandemics/prevention & control , Adolescent , Adult , Asian Continental Ancestry Group/statistics & numerical data , China/epidemiology , Disease Outbreaks/statistics & numerical data , Disease Transmission, Infectious/statistics & numerical data , Female , Humans , Male , Pandemics/statistics & numerical data , Surveys and Questionnaires , Young Adult
17.
Front Public Health ; 8: 609974, 2020.
Article in English | MEDLINE | ID: covidwho-993482

ABSTRACT

Background: COVID-19 developed into a global pandemic in 2020 and poses challenges regarding the prevention and control capabilities of countries. A large number of inbound travelers from other regions could lead to a renewed outbreak of COVID-19 in the local regions. Globally, as a result of the imbalance in the control of the epidemic, all countries are facing the risk of a renewed COVID-19 outbreak brought about by travelers from epidemic areas. Therefore, studies on a proper management of the inbound travelers are urgent. Methods: We collected a total of 4,733,414 inbound travelers and 174 COVID-19 diagnosed patients in Yunnan province from 21 January 2020 to 20 February 2020. Data on place of origin, travel history, age, and gender, as well as whether they had suspected clinical manifestations for inbound travelers in Yunnan were collected. The impact of inbound travelers on the local epidemic was analyzed with a collinear statistical analysis and the effect of the control measures on the epidemic was evaluated with a sophisticated modeling approach. Results: Of the 174 COVID-19 patients, 60.9% were not from Yunnan, and 76.4% had a history of travel in Hubei. The amount of new daily cases in Yunnan was significant correlated with the number of inbound travelers from Hubei and suspected cases among them. Using Susceptible-Exposed-Infectious-Recovered (SEIR) model analysis, we found that the prevention and control measures dropped the local R0 down to 1.07 in Yunnan province. Conclusions: Our preliminary analysis showed that the proper management of inbound travelers from outbreak areas has a significantly positive effect on the prevention and control of the virus. In the process of resettlement, some effective measures taken by Yunnan province may provide an important reference for preventing the renewed COVID-19 outbreak in other regions.


Subject(s)
/transmission , Disease Outbreaks/prevention & control , Disease Outbreaks/statistics & numerical data , Disease Transmission, Infectious/prevention & control , Pandemics/prevention & control , Pandemics/statistics & numerical data , Travel/statistics & numerical data , Adolescent , Adult , Aged , Aged, 80 and over , China/epidemiology , Disease Transmission, Infectious/statistics & numerical data , Female , Humans , Male , Middle Aged , Young Adult
18.
J Pediatric Infect Dis Soc ; 9(5): 613-616, 2020 Nov 10.
Article in English | MEDLINE | ID: covidwho-919283

ABSTRACT

We investigated of illness among household members of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children receiving medical care (n = 32). We identified 144 household contacts (HCs): 58 children and 86 adults. Forty-six percent of HCs developed symptoms consistent with coronavirus disease. Child-to-adult transmission was suspected in 7 cases.


Subject(s)
Betacoronavirus , Coronavirus Infections/transmission , Disease Transmission, Infectious/statistics & numerical data , Family , Pneumonia, Viral/transmission , Adolescent , Child , Child, Preschool , Coronavirus Infections/epidemiology , Cost of Illness , Female , Hospitalization/statistics & numerical data , Humans , Infant , Interviews as Topic , Male , Pandemics , Pneumonia, Viral/epidemiology , Surveys and Questionnaires
19.
Am J Otolaryngol ; 42(1): 102829, 2021.
Article in English | MEDLINE | ID: covidwho-909337

ABSTRACT

PURPOSE: The COVID-19 pandemic has led to concerns over transmission risk from healthcare procedures, especially when operating in the head and neck such as during surgical repair of facial fractures. This study aims to quantify aerosol and droplet generation from mandibular and midface open fixation and measure mitigation of airborne particles by a smoke evacuating electrocautery hand piece. MATERIALS AND METHODS: The soft tissue of the bilateral mandible and midface of two fresh frozen cadaveric specimens was infiltrated using a 0.1% fluorescein solution. Surgical fixation via oral vestibular approach was performed on each of these sites. Droplet splatter on the surgeon's chest, facemask, and up to 198.12 cm (6.5 ft) away from each surgical site was measured against a blue background under ultraviolet-A (UV-A) light. Aerosol generation was measured using an optical particle sizer. RESULTS: No visible droplet contamination was observed for any trials of mandible or midface fixation. Total aerosolized particle counts from 0.300-10.000 µm were increased compared to baseline following each use of standard electrocautery (n = 4, p < 0.001) but not with use of a suction evacuating electrocautery hand piece (n = 4, p = 0.103). Total particle counts were also increased during use of the powered drill (n = 8, p < 0.001). CONCLUSIONS: Risk from visible droplets during mandible and midface fixation is low. However, significant increases in aerosolized particles were measured after electrocautery use and during powered drilling. Aerosol dispersion is significantly decreased with the use of a smoke evacuating electrocautery hand piece.


Subject(s)
Aerosols/adverse effects , Disease Transmission, Infectious/statistics & numerical data , Intraoperative Period , Pandemics , /epidemiology , Humans , Mandible , United States/epidemiology
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