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2.
Nat Commun ; 13(1): 1012, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1709629

ABSTRACT

Mitigation of SARS-CoV-2 transmission from international travel is a priority. We evaluated the effectiveness of travellers being required to quarantine for 14-days on return to England in Summer 2020. We identified 4,207 travel-related SARS-CoV-2 cases and their contacts, and identified 827 associated SARS-CoV-2 genomes. Overall, quarantine was associated with a lower rate of contacts, and the impact of quarantine was greatest in the 16-20 age-group. 186 SARS-CoV-2 genomes were sufficiently unique to identify travel-related clusters. Fewer genomically-linked cases were observed for index cases who returned from countries with quarantine requirement compared to countries with no quarantine requirement. This difference was explained by fewer importation events per identified genome for these cases, as opposed to fewer onward contacts per case. Overall, our study demonstrates that a 14-day quarantine period reduces, but does not completely eliminate, the onward transmission of imported cases, mainly by dissuading travel to countries with a quarantine requirement.


Subject(s)
COVID-19/prevention & control , Communicable Diseases, Imported/prevention & control , Quarantine/legislation & jurisprudence , SARS-CoV-2/genetics , COVID-19/epidemiology , COVID-19/transmission , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/transmission , Contact Tracing , England/epidemiology , Genome, Viral/genetics , Genomics , Health Impact Assessment , Humans , SARS-CoV-2/classification , Travel/legislation & jurisprudence , Travel-Related Illness
3.
Proc Natl Acad Sci U S A ; 118(31)2021 08 03.
Article in English | MEDLINE | ID: covidwho-1319070

ABSTRACT

Since its outbreak in December 2019, the novel coronavirus 2019 (COVID-19) has spread to 191 countries and caused millions of deaths. Many countries have experienced multiple epidemic waves and faced containment pressures from both domestic and international transmission. In this study, we conduct a multiscale geographic analysis of the spread of COVID-19 in a policy-influenced dynamic network to quantify COVID-19 importation risk under different policy scenarios using evidence from China. Our spatial dynamic panel data (SDPD) model explicitly distinguishes the effects of travel flows from the effects of transmissibility within cities, across cities, and across national borders. We find that within-city transmission was the dominant transmission mechanism in China at the beginning of the outbreak and that all domestic transmission mechanisms were muted or significantly weakened before importation posed a threat. We identify effective containment policies by matching the change points of domestic and importation transmissibility parameters to the timing of various interventions. Our simulations suggest that importation risk is limited when domestic transmission is under control, but that cumulative cases would have been almost 13 times higher if domestic transmissibility had resurged to its precontainment level after importation and 32 times higher if domestic transmissibility had remained at its precontainment level since the outbreak. Our findings provide practical insights into infectious disease containment and call for collaborative and coordinated global suppression efforts.


Subject(s)
COVID-19/transmission , Communicable Diseases, Imported/transmission , COVID-19/epidemiology , COVID-19/prevention & control , China/epidemiology , Cities , Communicable Disease Control/legislation & jurisprudence , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/prevention & control , Humans , Models, Statistical , Risk , SARS-CoV-2 , Spatio-Temporal Analysis , Travel
4.
Travel Med Infect Dis ; 41: 102044, 2021.
Article in English | MEDLINE | ID: covidwho-1171225

ABSTRACT

BACKGROUND: Imported COVID-19 cases, if unchecked, can jeopardize the effort of domestic containment. We aim to find out what sustainable border control options for different entities (e.g., countries, states) exist during the reopening phases, given their own choice of domestic control measures. METHODS: We propose a SUIHR model, which has built-in imported risk and (1-tier) contact tracing to study the cross-border spreading and control of COVID-19. Under plausible parameter assumptions, we examine the effectiveness of border control policies, in combination with internal measures, to confine the virus and avoid reverting back to more restrictive life styles again. RESULTS: When the basic reproduction number R0 of COVID-19 exceeds 2.5, even 100% effective contact tracing alone is not enough to contain the spreading. For an entity that has completely eliminated the virus domestically, and resumes "normal", without mandatory institutional quarantine, even very strict border control measures combined with effective contact tracing can only delay another outbreak by 6 months. For entities employing a confining domestic control policy, non-increasing net imported cases is sufficient to remain open. CONCLUSIONS: Extremely strict border control in entities, where domestic spreading is currently eliminated (e.g., China), is justifiable. However such harsh measure are not necessary for other places. Entities successfully confining the virus by internal measures can open up to similar entities without additional border controls so long as the imported risk stays non-increasing. Opening the borders to entities lacking sufficient internal control of the virus should be exercised in combination with pre-departure screening and tests upon arrival.


Subject(s)
COVID-19/prevention & control , Communicable Disease Control/methods , Public Policy , Travel , Basic Reproduction Number , COVID-19/epidemiology , COVID-19/transmission , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Contact Tracing/methods , Disease Outbreaks/prevention & control , Government , Humans , Models, Theoretical , Pandemics/prevention & control , Quarantine/methods , SARS-CoV-2
7.
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)
COVID-19 , Communicable Disease Control , Communicable Diseases, Imported , Disease Transmission, Infectious , International Health Regulations , Quarantine , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/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 , SARS-CoV-2 , Travel/legislation & jurisprudence , Travel/statistics & numerical data
8.
Am J Trop Med Hyg ; 104(2): 490-495, 2020 Dec 10.
Article in English | MEDLINE | ID: covidwho-976421

ABSTRACT

As the COVID-19 pandemic continues, there is growing concordance and persisting conflicts on the virus and the disease process. We discuss limited transmissibility of the virus by asymptomatic and mild cases of COVID-19 patients in Bhutan. We followed up the secondary transmission of SARS-CoV-2 in the contacts of asymptomatic and mild COVID-19 patients in Bhutan. Bhutan had 33 confirmed COVID-19 cases in the country as of May 29, 2020. Of these, 22 (67%) were females. Except the first two cases (American tourists), the rest were Bhutanese living outside the country. The mean age of the Bhutanese patients was 26.3 (range 16-33) years. Close contacts of 27 of the 33 cases were followed up for signs and symptoms and COVID-19 positivity. The first two cases had 73 and 97 primary contacts, respectively, and equal number of secondary contacts (224). From the third case, a mandatory 21-day facility quarantine was instituted, all primary contacts were facility quarantined, and there were no secondary contacts. In total, the 27 cases had 1,095 primary contacts and 448 secondary contacts. Of these, 75 individuals were categorized as definite high-risk contacts. Secondary transmission occurred in seven high-risk contacts. Therefore, the overall secondary transmission was 9.0% (7/75) and 0.6% (7/1,095) among the high-risk and primary contacts, respectively. No transmission occurred in the secondary contacts. In contrast to several reports indicating high transmissibility of SARS-CoV-2 in contacts of confirmed cases, the mostly young, asymptomatic, and mild cases of COVID-19 in Bhutan showed limited secondary transmission.


Subject(s)
COVID-19/transmission , Carrier State/virology , Communicable Diseases, Imported/transmission , Communicable Diseases, Imported/virology , Adolescent , Adult , Aged , Bhutan/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , Communicable Diseases, Imported/epidemiology , Contact Tracing , Female , Humans , Male , Middle Aged , Quarantine , Risk Factors , SARS-CoV-2/pathogenicity , Travel-Related Illness , Young Adult
9.
Epidemiology ; 32(1): 79-86, 2021 01.
Article in English | MEDLINE | ID: covidwho-972117

ABSTRACT

BACKGROUND: We hypothesize that comprehensive surveillance of COVID-19 in Singapore has facilitated early case detection and prompt contact tracing and, with community-based measures, contained spread. We assessed the effectiveness of containment measures by estimating transmissibility (effective reproduction number, (Equation is included in full-text article.)) over the course of the outbreak. METHODS: We used a Bayesian data augmentation framework to allocate infectors to infectees with no known infectors and determine serial interval distribution parameters via Markov chain Monte Carlo sampling. We fitted a smoothing spline to the number of secondary cases generated by each infector by respective onset dates to estimate (Equation is included in full-text article.)and evaluated increase in mean number of secondary cases per individual for each day's delay in starting isolation or quarantine. RESULTS: As of April 1, 2020, 1000 COVID-19 cases were reported in Singapore. We estimated a mean serial interval of 4.6 days [95% credible interval (CI) = 4.2, 5.1] with a SD of 3.5 days (95% CI = 3.1, 4.0). The posterior mean (Equation is included in full-text article.)was below one for most of the time, peaking at 1.1 (95% CI = 1.0, 1.3) on week 9 of 2020 due to a spreading event in one of the clusters. Eight hundred twenty-seven (82.7%) of cases infected less than one person on average. Over an interval of 7 days, the incremental mean number of cases generated per individual for each day's delay in starting isolation or quarantine was 0.03 cases (95% CI = 0.02, 0.05). CONCLUSIONS: We estimate that robust surveillance, active case detection, prompt contact tracing, and quarantine of close contacts kept (Equation is included in full-text article.)below one.


Subject(s)
COVID-19/prevention & control , Communicable Disease Control/methods , Health Policy , Basic Reproduction Number , Bayes Theorem , COVID-19/epidemiology , COVID-19/transmission , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Contact Tracing , Early Diagnosis , Epidemiological Monitoring , Humans , Markov Chains , Mass Screening , Monte Carlo Method , Singapore/epidemiology , Travel
10.
Transfusion ; 60(9): 1987-1997, 2020 09.
Article in English | MEDLINE | ID: covidwho-796294

ABSTRACT

Risk assessments of transfusion-transmitted emerging infectious diseases (EIDs) are complicated by the fact that blood donors' demographics and behaviors can be different from the general population. Therefore, when assessing potential blood donor exposure to EIDs, the use of general population characteristics, such as U.S. travel statistics, may invoke uncertainties that result in inaccurate estimates of blood donor exposure. This may, in turn, lead to the creation of donor deferral policies that do not match actual risk. STUDY DESIGN AND METHODS: This article reports on the development of a system to rapidly assess EID risks for a nationally representative portion of the U.S. blood donor population. To assess the effectiveness of this system, a test survey was developed and deployed to a statistically representative sample frame of blood donors from five blood collecting organizations. Donors were directed to an online survey to ascertain their recent travel and potential exposure to Middle East respiratory syndrome coronavirus (MERS-CoV). RESULTS: A total of 7128 responses were received from 54 256 invitations. The age-adjusted estimated total number of blood donors potentially exposed to MERS-CoV was approximately 15 640 blood donors compared to a lower U.S. general population-based estimate of 9610 blood donors. CONCLUSION: The structured donor demographic sample-based data provided an assessment of blood donors' potential exposure to an emerging pathogen that was 63% larger than the U.S. population-based estimate. This illustrates the need for tailored blood donor-based EID risk assessments that provide more specific demographic risk intelligence and can inform appropriate regulatory decision making.


Subject(s)
Blood Donors , Blood Transfusion , Blood-Borne Infections/epidemiology , Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Imported/epidemiology , Coronavirus Infections/epidemiology , Environmental Exposure , Risk Assessment/methods , Surveys and Questionnaires , Travel-Related Illness , Adolescent , Adult , Aged , Aged, 80 and over , Blood Banks , Blood Donors/statistics & numerical data , Blood-Borne Infections/blood , Blood-Borne Infections/prevention & control , Blood-Borne Infections/transmission , Communicable Diseases, Emerging/blood , Communicable Diseases, Emerging/prevention & control , Communicable Diseases, Emerging/transmission , Communicable Diseases, Imported/blood , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Coronavirus Infections/blood , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Decision Making , Female , Humans , Male , Middle Aged , Middle East , Middle East Respiratory Syndrome Coronavirus , Sample Size , Sampling Studies , Transfusion Reaction/prevention & control , United States/epidemiology , Young Adult
11.
Math Biosci ; 329: 108442, 2020 11.
Article in English | MEDLINE | ID: covidwho-695282

ABSTRACT

On February 5 the Japanese government ordered the passengers and crew on the Diamond Princess to start a two week quarantine after a former passenger tested positive for COVID-19. During the quarantine the virus spread rapidly throughout the ship. By February 20, there were 651 cases. We model this quarantine with a SEIR model including asymptomatic infections with differentiated shipboard roles for crew and passengers. The study includes the derivation of the basic reproduction number and simulation studies showing the effect of quarantine with COVID-19 or influenza on the total infection numbers. We show that quarantine on a ship with COVID-19 will lead to significant disease spread if asymptomatic infections are not identified. However, if the majority of the crew and passengers are immune or vaccinated to COVID-19, then quarantine would slow the spread. We also show that a disease similar to influenza, even with a ship with a fully susceptible crew and passengers, could be contained through quarantine measures.


Subject(s)
Asymptomatic Infections , Betacoronavirus , Coronavirus Infections/prevention & control , Coronavirus Infections/transmission , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Pneumonia, Viral/transmission , Quarantine , Ships , Travel , Basic Reproduction Number/statistics & numerical data , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Computer Simulation , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Humans , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Influenza, Human/transmission , Japan/epidemiology , Mathematical Computing , Models, Biological , Pneumonia, Viral/epidemiology , Quarantine/methods , SARS-CoV-2 , Travel Medicine , Travel-Related Illness
12.
Emerg Infect Dis ; 26(9)2020 09.
Article in English | MEDLINE | ID: covidwho-625736

ABSTRACT

An asymptomatic person infected with severe acute respiratory syndrome coronavirus 2 returned to Heilongjiang Province, China, after international travel. The traveler's neighbor became infected and generated a cluster of >71 cases, including cases in 2 hospitals. Genome sequences of the virus were distinct from viral genomes previously circulating in China.


Subject(s)
Betacoronavirus , Communicable Diseases, Imported/epidemiology , Coronavirus Infections/epidemiology , Disease Outbreaks , Pneumonia, Viral/epidemiology , Adult , Aged , Asymptomatic Infections/epidemiology , COVID-19 , China/epidemiology , Communicable Diseases, Imported/transmission , Communicable Diseases, Imported/virology , Coronavirus Infections/transmission , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/transmission , SARS-CoV-2 , Travel
14.
Lancet Infect Dis ; 20(8): 920-928, 2020 08.
Article in English | MEDLINE | ID: covidwho-276988

ABSTRACT

BACKGROUND: In December, 2019, the newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, causing COVID-19, a respiratory disease presenting with fever, cough, and often pneumonia. WHO has set the strategic objective to interrupt spread of SARS-CoV-2 worldwide. An outbreak in Bavaria, Germany, starting at the end of January, 2020, provided the opportunity to study transmission events, incubation period, and secondary attack rates. METHODS: A case was defined as a person with SARS-CoV-2 infection confirmed by RT-PCR. Case interviews were done to describe timing of onset and nature of symptoms and to identify and classify contacts as high risk (had cumulative face-to-face contact with a confirmed case for ≥15 min, direct contact with secretions or body fluids of a patient with confirmed COVID-19, or, in the case of health-care workers, had worked within 2 m of a patient with confirmed COVID-19 without personal protective equipment) or low risk (all other contacts). High-risk contacts were ordered to stay at home in quarantine for 14 days and were actively followed up and monitored for symptoms, and low-risk contacts were tested upon self-reporting of symptoms. We defined fever and cough as specific symptoms, and defined a prodromal phase as the presence of non-specific symptoms for at least 1 day before the onset of specific symptoms. Whole genome sequencing was used to confirm epidemiological links and clarify transmission events where contact histories were ambiguous; integration with epidemiological data enabled precise reconstruction of exposure events and incubation periods. Secondary attack rates were calculated as the number of cases divided by the number of contacts, using Fisher's exact test for the 95% CIs. FINDINGS: Patient 0 was a Chinese resident who visited Germany for professional reasons. 16 subsequent cases, often with mild and non-specific symptoms, emerged in four transmission generations. Signature mutations in the viral genome occurred upon foundation of generation 2, as well as in one case pertaining to generation 4. The median incubation period was 4·0 days (IQR 2·3-4·3) and the median serial interval was 4·0 days (3·0-5·0). Transmission events were likely to have occurred presymptomatically for one case (possibly five more), at the day of symptom onset for four cases (possibly five more), and the remainder after the day of symptom onset or unknown. One or two cases resulted from contact with a case during the prodromal phase. Secondary attack rates were 75·0% (95% CI 19·0-99·0; three of four people) among members of a household cluster in common isolation, 10·0% (1·2-32·0; two of 20) among household contacts only together until isolation of the patient, and 5·1% (2·6-8·9; 11 of 217) among non-household, high-risk contacts. INTERPRETATION: Although patients in our study presented with predominately mild, non-specific symptoms, infectiousness before or on the day of symptom onset was substantial. Additionally, the incubation period was often very short and false-negative tests occurred. These results suggest that although the outbreak was controlled, successful long-term and global containment of COVID-19 could be difficult to achieve. FUNDING: All authors are employed and all expenses covered by governmental, federal state, or other publicly funded institutions.


Subject(s)
Betacoronavirus/isolation & purification , Communicable Diseases, Imported/transmission , Coronavirus Infections/transmission , Disease Outbreaks , Disease Transmission, Infectious , Pneumonia, Viral/transmission , Travel-Related Illness , Adolescent , Adult , Betacoronavirus/classification , Betacoronavirus/genetics , COVID-19 , Child , Child, Preschool , China , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/pathology , Communicable Diseases, Imported/virology , Coronavirus Infections/epidemiology , Germany/epidemiology , Humans , Interviews as Topic , Middle Aged , Mutation , Pandemics , Pneumonia, Viral/epidemiology , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Risk Assessment , SARS-CoV-2 , Travel , Young Adult
15.
Rev Inst Med Trop Sao Paulo ; 62: e30, 2020.
Article in English | MEDLINE | ID: covidwho-246727

ABSTRACT

We conducted the genome sequencing and analysis of the first confirmed COVID-19 infections in Brazil. Rapid sequencing coupled with phylogenetic analyses in the context of travel history corroborate multiple independent importations from Italy and local spread during the initial stage of COVID-19 transmission in Brazil.


Subject(s)
Betacoronavirus/genetics , Communicable Diseases, Imported/transmission , Coronavirus Infections/transmission , Pandemics , Pneumonia, Viral/transmission , Aged , Brazil/epidemiology , COVID-19 , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/virology , Coronavirus Infections/epidemiology , Humans , Middle Aged , Phylogeny , Pneumonia, Viral/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2
17.
J Microbiol Immunol Infect ; 53(3): 467-472, 2020 Jun.
Article in English | MEDLINE | ID: covidwho-17540

ABSTRACT

BACKGROUND: The World Health Organization (WHO) has declared the current outbreak of the novel coronavirus (COVID-19) a global pandemic. Many countries are facing increasing numbers of COVID-19 cases, which are, in their origin mostly attributed to regular international flight connections with China. This study aims to investigate this relation by analyzing available data on air traffic volume and the spread of COVID-19 cases. METHODS: and findings: We analyzed available data on current domestic and international passenger volume and flight routes and compared these to the distribution of domestic and international COVID-19 cases. RESULTS: Our data indicate a strong linear correlation between domestic COVID-19 cases and passenger volume for regions within China (r2 = 0.92, p = 0.19) and a significant correlation between international COVID-19 cases and passenger volume (r2 = 0.98, p < 0.01). CONCLUSIONS: The number of flight routes as well as total passenger volume are highly relevant risk factors for the spread of current COVID-19. Multiple regions within Asia, as well as some in North America and Europe are at serious risk of constant exposure to COVID-19 from China and other highly infected countries. Risk for COVID-19 exposure remains relatively low in South America and Africa. If adequate measures are taken, including on-site disease detection and temporary passenger quarantine, limited but not terminated air traffic can be a feasible option to prevent a long-term crisis. Reasonable risk calculations and case evaluations per passenger volume are crucial aspects which must be considered when reducing international flights.


Subject(s)
Air Travel/statistics & numerical data , Communicable Diseases, Imported/prevention & control , Coronavirus Infections/transmission , Pandemics/prevention & control , Pneumonia, Viral/transmission , COVID-19 , China , Communicable Diseases, Imported/transmission , Coronavirus Infections/prevention & control , Humans , Pneumonia, Viral/prevention & control , Public Health
18.
Science ; 368(6489): 395-400, 2020 04 24.
Article in English | MEDLINE | ID: covidwho-5137

ABSTRACT

Motivated by the rapid spread of coronavirus disease 2019 (COVID-19) in mainland China, we use a global metapopulation disease transmission model to project the impact of travel limitations on the national and international spread of the epidemic. The model is calibrated on the basis of internationally reported cases and shows that, at the start of the travel ban from Wuhan on 23 January 2020, most Chinese cities had already received many infected travelers. The travel quarantine of Wuhan delayed the overall epidemic progression by only 3 to 5 days in mainland China but had a more marked effect on the international scale, where case importations were reduced by nearly 80% until mid-February. Modeling results also indicate that sustained 90% travel restrictions to and from mainland China only modestly affect the epidemic trajectory unless combined with a 50% or higher reduction of transmission in the community.


Subject(s)
Betacoronavirus , Communicable Diseases, Imported/epidemiology , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Quarantine , Travel , COVID-19 , China/epidemiology , Communicable Diseases, Imported/prevention & control , Communicable Diseases, Imported/transmission , Computer Simulation , Coronavirus Infections/prevention & control , Disease Outbreaks , Humans , Incidence , Internationality , Models, Statistical , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , SARS-CoV-2
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