Characteristics of Clinically Asymptomatic Patients with SARS-CoV-2 Infections, Case Series

Transmission of SARS-CoV-2 Associated with Cruise Ship Travel: A Systematic Review

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.

Maximizing the Role of Emergency Medical Services in COVID-19 Response

The Centers for Disease Control and Prevention define 6 intervals of a pandemic: (1) investigation of cases, (2) recognition of the increased potential for ongoing transmission, (3) initiation of a pandemic wave, (4) acceleration of a pandemic wave, (5) deceleration of a pandemic wave, and (6) preparation for future pandemic waves. Each of these stages has 8 domains. Following China's coronavirus disease 2019 (COVID-19) outbreak announcement, Israel's National Emergency Medical Services (EMS) Organization immediately began working in conjunction with the Ministry of Health (MOH) to address the threat of the COVID-19 outbreak. This article will describe how a national EMS organization acted according to these pandemic intervals and domains. In the initial stages, EMS managed a checkpoint in the international airport voluntarily testing people for febrile symptoms. Calls to the dispatch centers that aroused the suspicion of COVID-19 resulted in EMS transport to the hospital with protective gear. During the period of first exposure, the scope of the medical emergency number was increased to include questions concerning coronavirus, telemedicine, and home sampling by protected EMS workers. In the contagion stages, epidemiological tests were conducted by the MOH, and EMS began operating dedicated telephone triage, mass drive-through sampling, and finally, administration of vaccinations.

Asymptomatic SARS-CoV-2 infection: A systematic review and meta-analysis

Quantification of asymptomatic infections is fundamental for effective public health responses to the COVID-19 pandemic. Discrepancies regarding the extent of asymptomaticity have arisen from inconsistent terminology as well as conflation of index and secondary cases which biases toward lower asymptomaticity. We searched PubMed, Embase, Web of Science, and World Health Organization Global Research Database on COVID-19 between January 1, 2020 and April 2, 2021 to identify studies that reported silent infections at the time of testing, whether presymptomatic or asymptomatic. Index cases were removed to minimize representational bias that would result in overestimation of symptomaticity. By analyzing over 350 studies, we estimate that the percentage of infections that never developed clinical symptoms, and thus were truly asymptomatic, was 35.1% (95% CI: 30.7 to 39.9%). At the time of testing, 42.8% (95% prediction interval: 5.2 to 91.1%) of cases exhibited no symptoms, a group comprising both asymptomatic and presymptomatic infections. Asymptomaticity was significantly lower among the elderly, at 19.7% (95% CI: 12.7 to 29.4%) compared with children at 46.7% (95% CI: 32.0 to 62.0%). We also found that cases with comorbidities had significantly lower asymptomaticity compared to cases with no underlying medical conditions. Without proactive policies to detect asymptomatic infections, such as rapid contact tracing, prolonged efforts for pandemic control may be needed even in the presence of vaccination.

Academic activism on behalf of children during the COVID-19 pandemic in Israel; beyond public health advocacy

Among the challenges presented by the SARS-CoV2 pandemic are those related to balancing societal priorities with averting threats to population health. In this exceptional context a group of Israeli physicians and public health scholars (multidisciplinary academic group on children and coronavirus [MACC]) coalesced, examining the role of children in viral transmission and assessing the necessity and consequences of restricted in-class education. Combining critical appraisal and analytical skills with public health experience, MACC advocated for safe and monitored school re-opening, stressing the importance of education as a determinant of health, continuously weighing this stance against evolving COVID-19-risk data. MACC's activities included offering research-based advice to government agencies including Ministries of Health, Finance, and Education. In a setting where government bodies were faced with providing practical solutions to both decreasing disease transmission and maintaining society's vital activities, and various advisors presented decision-makers with disparate views, MACC contributed epidemiological, clinical and health policy expertise to the debate regarding school closure as a pandemic control measure, and adaptations required for safe re-opening. In this paper, we describe the evolution, activities, policy inputs and media profile of MACC, and discuss the role of academics in advocacy and activism in the midst of an unprecedented public health crisis. A general lesson learned is that academics, based on the rigor of their scientific work and their perceived objectivity, can and should be mobilized to pursue and promote policies based on shared societal values as well as empiric data, even when considerable uncertainty exists about the appropriate course of action. Mechanisms should be in place to open channels to multidisciplinary academic groups and bring their input to bear on decision-making.

COVID-19 in Workplaces: Secondary Transmission

OBJECTIVES

Coronavirus disease (COVID-19) contagion at work is well studied for healthcare workers, however it is not enough assessed in other working settings. Very little is known, indeed, about the risk of COVID-19 transmission through occupational exposure in non-health working places. This study aims to describe a COVID-19 cluster among workers in an office in Italy.

METHODS

This was a retrospective observational study on a cluster of COVID-19 that occurred from 20 November through 3 December 2020 in a group of six colleagues (A-F) working in the same office full time 5 days a week, 8 h a day. The workers used the following prevention measures: social distancing (desks were >1 m, 1.76-5.01 m range), plexiglas panels, hands disinfection, and use of face mask. However, they did not wear face mask when in static position sitting at their desk and they did not aerate the place frequently.

RESULTS

The disease spread from one worker (subject A) to four (80%) of the five colleagues (subjects B-F). Only subject D was negative to COVID-19 on 14 days after last contact with subject A (20 November 2020) as confirmed by nasopharyngeal swab testing. Subject D, in particular, did not contact subject A in the 48 h before symptoms onset. COVID-19 positivity of subject A was promptly communicated to the colleagues, who started self-isolation from their relatives and none of their households were infected. COVID-19 transmission was observed only in households of subject A.

CONCLUSIONS

The rapid communication of COVID-19 positivity to the colleagues and the prompt isolation of index case's close contacts allowed to eliminate the secondary transmission to their households. The contagion of index case's colleagues occurred from second day before symptoms onset. Distancing of >1 m, use of plexiglass panels, sanitizing hand gel, and inconstant use of face mask may not be enough for infection prevention in closed places with poor ventilation and high occupancy.

Fatal pulmonary arterial thrombosis in a COVID-19 patient, with asymptomatic history, occurred after swab negativization

BACKGROUND

A considerable number of SARS-CoV-2 infected individuals could be asymptomatic and don't need medical treatment. The clinical spectrum of SARS-CoV-2 infection ranges from asymptomatic cases, medium-intensity forms with mild to moderate symptoms, to severe ones with bilateral pneumonia and respiratory distress. In cases with severe presentation of SARS-CoV-2 infection, the induction of hypercoagulability is one of the pathophysiological mechanism that can contribute to death.

CASE PRESENTATION

Here, we reported autoptic evidences of thrombotic pulmonary arterial fatal lesions in an asymptomatic COVID-19 patient, after swab negativization. Whole body complete post-mortem examination was performed, showing the presence of a large thrombus occluding the main pulmonary artery that was the cause of death. Histopathological analysis showed heterogeneous pattern of pathological changes in the lung tissue with numerous vascular thrombi, inflammatory cardiomyopathy and other histopathological modifications in kidneys, spleen and liver.

CONCLUSIONS

This study provides evidences that also asymptomatic patients may be at risk to develop thrombotic complications. An appropriate diagnostic screening for thrombotic complications and the early treatment recommendations of antithrombotic drugs could represent an important topic even in asymptomatic individuals.