Dynamic Network Strategies for SARS-CoV-2 Control on a Cruise Ship.
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ABSTRACT:
SUBMITTER: Jenness SM
PROVIDER: S-EPMC7480061 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:SARS-CoV-2 outbreaks have occurred on several nautical vessels, driven by the high-density contact networks on these ships. Optimal strategies for prevention and control that account for realistic contact networks are needed. We developed a network-based transmission model for SARS-CoV-2 on the Diamond Princess outbreak to characterize transmission dynamics and to estimate the epidemiological impact of outbreak control and prevention measures. This model represented the dynamic multi-layer network structure of passenger-passenger, passenger-crew, and crew-crew contacts, both before and after the large-scale network lockdown imposed on the ship in response to the disease outbreak. Model scenarios evaluated variations in the timing of the network lockdown, reduction in contact intensity within the sub-networks, and diagnosis-based case isolation on outbreak prevention. We found that only extreme restrictions in contact patterns during network lockdown and idealistic clinical response scenarios could avert a major COVID-19 outbreak. Contact network changes associated with adequate outbreak prevention were the restriction of passengers to their cabins, with limited passenger-crew contacts. Clinical response strategies required for outbreak prevention may be infeasible in many cruise settings: early mass screening with an ideal PCR test (100 % sensitivity) and immediate case isolation upon diagnosis. Personal protective equipment (e.g., facemasks) had limited impact in this environment because the majority of transmissions after the ship lockdown occurred between passengers in cabins where masks were not consistently used. Public health restrictions on optional leisure activities like these should be considered until longer-term effective solutions such as a COVID-19 vaccine become widely available.
| S-EPMC8372454 | biostudies-literature
Project description:Background: Maritime and river travel may be associated with respiratory viral spread via infected passengers and/or crew and potentially through other transmission routes. The transmission models of SARS-CoV-2 associated with cruise ship travel are based on transmission dynamics of other respiratory viruses. We aimed to provide a summary and evaluation of relevant data on SARS-CoV-2 transmission aboard cruise ships, report policy implications, and highlight research gaps. Methods: We searched four electronic databases (up to 26 May 2022) and included studies on SARS-CoV-2 transmission aboard cruise ships. The quality of the studies was assessed based on five criteria, and relevant findings were reported. Results: We included 23 papers on onboard SARS-CoV-2 transmission (with 15 reports on different aspects of the outbreak on Diamond Princess and nine reports on other international cruises), 2 environmental studies, and 1 systematic review. Three articles presented data on both international cruises and the Diamond Princess. The quality of evidence from most studies was low to very low. Index case definitions were heterogeneous. The proportion of traced contacts ranged from 0.19 to 100%. Studies that followed up >80% of passengers and crew reported attack rates (AR) up to 59%. The presence of a distinct dose−response relationship was demonstrated by findings of increased ARs in multi-person cabins. Two studies performed viral cultures with eight positive results. Genomic sequencing and phylogenetic analyses were performed in individuals from three cruises. Two environmental studies reported PCR-positive samples (cycle threshold range 26.21−39.00). In one study, no infectious virus was isolated from any of the 76 environmental samples. Conclusion: Our review suggests that crowding and multiple persons per cabin were associated with an increased risk of transmission on cruise ships. Variations in design, methodology, and case ascertainment limit comparisons across studies and quantification of transmission risk. Standardized guidelines for conducting and reporting studies on cruise ships of acute respiratory infection transmission should be developed.
| S-EPMC9610645 | biostudies-literature
Project description:In the initial phase of the novel coronavirus disease (COVID-19) pandemic, a large-scale cluster on the cruise ship Diamond Princess (DP) emerged in Japan. Genetic analysis of the DP strains has provided important information for elucidating the possible transmission process of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on a cruise ship. However, genome-based analyses of SARS-CoV-2 detected in large-scale cruise ship clusters other than the DP cluster have rarely been reported. In the present study, whole-genome sequences of 94 SARS-CoV-2 strains detected in the second large cruise ship cluster, which emerged on the Costa Atlantica (CA) in Japan, were characterized to understand the evolution of the virus in a crowded and confined place. Phylogenetic and haplotype network analysis indicated that the CA strains were derived from a common ancestral strain introduced on the CA cruise ship and spread in a superspreading event-like manner, resulting in several mutations that might have affected viral characteristics, including the P681H substitution in the spike protein. Moreover, there were significant genetic distances between CA strains and other strains isolated in different environments, such as cities under lockdown. These results provide new insights into the unique evolution patterns of SARS-CoV-2 in the CA cruise ship cluster.
| S-EPMC8778844 | biostudies-literature
Project description:A key unknown for SARS-CoV-2 is how asymptomatic infections contribute to transmission. We used a transmission model with asymptomatic and presymptomatic states, calibrated to data on disease onset and test frequency from the Diamond Princess cruise ship outbreak, to quantify the contribution of asymptomatic infections to transmission. The model estimated that 74% (70-78%, 95% posterior interval) of infections proceeded asymptomatically. Despite intense testing, 53% (51-56%) of infections remained undetected, most of them asymptomatic. Asymptomatic individuals were the source for 69% (20-85%) of all infections. The data did not allow identification of the infectiousness of asymptomatic infections, however low ranges (0-25%) required a net reproduction number for individuals progressing through presymptomatic and symptomatic stages of at least 15. Asymptomatic SARS-CoV-2 infections may contribute substantially to transmission. Control measures, and models projecting their potential impact, need to look beyond the symptomatic cases if they are to understand and address ongoing transmission.
| S-EPMC7527238 | biostudies-literature
Project description:The Diamond Princess cruise ship was put under quarantine offshore Yokohama, Japan, after a passenger who disembarked in Hong Kong was confirmed as a coronavirus disease 2019 case. We performed whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) directly from PCR+ clinical specimens and conducted a phylogenetic analysis of the outbreak. All tested isolates exhibited a transversion at G11083T, suggesting that SARS-CoV-2 dissemination on the Diamond Princess originated from a single introduction event before the quarantine started. Although further spreading might have been prevented by quarantine, some progeny clusters could be linked to transmission through mass-gathering events in the recreational areas and direct transmission among passengers who shared cabins during the quarantine. This study demonstrates the usefulness of haplotype network/phylogeny analysis in identifying potential infection routes.
| S-EPMC7443927 | biostudies-literature
Project description:BACKGROUND:A cruise ship is a closed-off environment that simulates the basic functioning of a city in terms of living conditions and interpersonal interactions. Thus, the Diamond Princess cruise ship, which was quarantined because of an onboard outbreak of COVID-19 in February, 2020, provides an opportunity to define the shedding pattern of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and patient antibody responses before and after the onset of symptoms. METHODS:We recruited adult (?18 years) passengers from Hong Kong who had been on board the Diamond Princess cruise ship docked in Yokohama, Japan in February, 2020. All participants had been found to be negative for SARS-CoV-2 by RT-PCR 4 days before disembarking and were transferred to further quarantine in a public estate in Hong Kong, where they were recruited. Participants were prospectively screened by quantitative RT-PCR (RT-qPCR) of nasopharyngeal and throat swabs, and serum IgG and IgM against internal nucleoprotein and the surface spike receptor-binding protein (RBD) of SARS-CoV-2 at baseline (upon entering quarantine) and on days 4, 8, and 12 of quarantine. FINDINGS:On Feb 22, 2020, 215 adults were recruited, of whom nine (4%; 95% CI 2-8) were positive for SARS-CoV-2 by RT-qPCR or serology and were hospitalised. Of these nine patients, nasopharyngeal swab RT-qPCR was positive in eight patients (89%; 57-99) at baseline. All nine patients were positive for anti-RBD IgG by day 8. Eight (89%; 57-99) were simultaneously positive for nasopharyngeal swab RT-PCR and anti-RBD IgG. One patient who was positive for anti-RBD IgG and had a negative viral load had multifocal peripheral ground-glass changes on high-resolution CT that were typical of COVID-19. Five patients (56%; 27-81) with ground-glass changes on high-resolution CT were found to have higher anti-nucleoprotein-IgG OD values on day 8 and 12 and anti-RBD IgG OD value on day 12 than patients without ground-glass changes. Six (67%; 35-88) patients remained asymptomatic throughout the 14-day quarantine period. INTERPRETATION:Patients with COVID-19 can develop asymptomatic lung infection with viral shedding and those with evidence of pneumonia on imaging tend to have an increased antibody response. Positive IgG or IgM confirmed infection of COVID-19 in both symptomatic and asymptomatic patients. A combination of RT-PCR and serology should be implemented for case finding and contact tracing to facilitate early diagnosis, prompt isolation, and treatment. FUNDING:Shaw Foundation Hong Kong; Sanming-Project of Medicine (Shenzhen); High Level-Hospital Program (Guangdong Health Commission).
| S-EPMC7292581 | biostudies-literature
Project description:BackgroundProlonged periods of confined living on a cruise ship increase the risk for respiratory disease transmission. We describe the epidemiology and clinical characteristics of a SARS-CoV-2 outbreak in Australian passengers on the Diamond Princess cruise ship and provide recommendations to mitigate future cruise ship outbreaks.MethodsWe conducted a retrospective cohort study of Australian passengers who travelled on the Diamond Princess from 20 January until 4 February 2020 and were either hospitalised, remained in Japan or repatriated. The main outcome measures included an epidemic curve, demographics, symptoms, clinical and radiological signs, risk factors and length of time to clear infection.ResultsAmong 223 Australian passengers, 56 were confirmed SARS-CoV-2 positive. Forty-nine cases had data available and of these over 70% had symptoms consistent with COVID-19. Of symptomatic cases, 17% showed signs and symptoms before the ship implemented quarantine and a further two-thirds had symptoms within one incubation period of quarantine commencing. Prior to ship-based quarantine, exposure to a close contact or cabin mate later confirmed SARS-CoV-2 positive was associated with a 3.78 fold (95% CI, 2.24-6.37) higher risk of COVID-19 acquisition compared to non-exposed passengers. Exposure to a positive cabin mate during the ship's quarantine carried a relative risk of 6.18 (95% CI, 1.96-19.46) of developing COVID-19. Persistently asymptomatic cases represented 29% of total cases. The median time to the first of two consecutive negative PCR-based SARS-CoV-2 assays was 13 days for asymptomatic cases and 19 days for symptomatic cases (p = 0.002).ConclusionShip based quarantine was effective at reducing transmission of SARS-CoV-2 amongst Australian passengers, but the risk of infection was higher if an individual shared a cabin or was a close contact of a confirmed case. Managing COVID-19 in cruise ship passengers is challenging and requires enhanced health measures and access to onshore quarantine and isolation facilities.
| S-EPMC8423262 | biostudies-literature
Project description:An outbreak of norovirus gastroenteritis affected passengers on two consecutive cruises of ship X and continued on 4 subsequent cruises despite a 1-week sanitization. We documented transmission by food and person-to-person contact; persistence of virus despite sanitization onboard, including introductions of new strains; and seeding of an outbreak on land.
| S-EPMC3294347 | biostudies-literature
Project description:An outbreak of COVID-19 occurred on the Diamond Princess cruise ship in January and February 2020 in Japan. We analysed information on the cases of infection to infer whether airborne transmission of SARS-CoV-2, the causative agent of COVID-19, had occurred between cabins. We infer from our analysis that most infections in passengers started on 28 January and were completed by 6 February, except in those who shared a cabin with another infected passenger. The distribution of the infected cabins was random, and no spatial cluster of the infected can be identified. We infer that the ship's central air-conditioning system for passenger's cabins did not play a role in SARS-CoV-2 transmission, i.e. airborne transmission did not occur between cabins during the outbreak, suggesting that the sufficient ventilation was provided. We also infer that the ship's cabin drainage system did not play a role. Most transmission appears to have occurred in the public areas of the cruise ship, likely due to crowding and insufficient ventilation in some of these areas.
| S-EPMC8046742 | biostudies-literature
Project description:BackgroundThere is a raising concern of a higher infectious Omicron BA.2 variant and the latest BA.4, BA.5 variant, made it more difficult in the mitigation process against COVID-19 pandemic. Our study aimed to find optimal control strategies by transmission of dynamic model from novel invasion theory.MethodsBased on the public data sources from January 31 to May 31, 2022, in four cities (Nanjing, Shanghai, Shenzhen and Suzhou) of China. We segmented the theoretical curves into five phases based on the concept of biological invasion. Then, a spatial autocorrelation analysis was carried out by detecting the clustering of the studied areas. After that, we choose a mathematical model of COVID-19 based on system dynamics methodology to simulate numerous intervention measures scenarios. Finally, we have used publicly available migration data to calculate spillover risk.ResultsEpidemics in Shanghai and Shenzhen has gone through the entire invasion phases, whereas Nanjing and Suzhou were all ended in the establishment phase. The results indicated that Rt value and public health and social measures (PHSM)-index of the epidemics were a negative correlation in all cities, except Shenzhen. The intervention has come into effect in different phases of invasion in all studied cities. Until the May 31, most of the spillover risk in Shanghai remained above the spillover risk threshold (18.81-303.84) and the actual number of the spillovers (0.94-74.98) was also increasing along with the time. Shenzhen reported Omicron cases that was only above the spillover risk threshold (17.92) at the phase of outbreak, consistent with an actual partial spillover. In Nanjing and Suzhou, the actual number of reported cases did not exceed the spillover alert value.ConclusionsBiological invasion is positioned to contribute substantively to understanding the drivers and mechanisms of the COVID-19 spread and outbreaks. After evaluating the spillover risk of cities at each invasion phase, we found the dynamic zero-COVID strategy implemented in four cities successfully curb the disease epidemic peak of the Omicron variant, which was highly correlated to the way to perform public health and social measures in the early phases right after the invasion of the virus.
| S-EPMC9701379 | biostudies-literature