Close Contacts Of COVID-19 Patients Research Articles

Real-world effectiveness of an intranasal spray A8G6 antibody cocktail in the post-exposure prophylaxis of COVID-19

Previously, we identified an antibody combination A8G6 that showed promising efficacy in COVID-19 animal models and favorable safety profile in preclinical models as well as in a first-in-human trial. To evaluate the real-word efficacy of A8G6 neutralizing antibody nasal spray in post-exposure prophylaxis of COVID-19, an open-label, non-randomized, two-arm, blank-controlled, investigator-initiated trial was conducted in Chongqing, China (the register number: ChiCTR2200066416). High-risk healthy participants (18–65 years) within 72 h after close contact to COVID-19 patients were recruited and received a three-dose (1.4 mg/dose) A8G6 treatment daily or no treatment (blank control) for 7 consecutive days. SARS-CoV-2 infection occurred in 151/340 (44.4%) subjects in the blank control group and 12/173 (6.9%) subjects in the A8G6 treatment group. The prevention efficacy of the A8G6 treatment within 72 h exposure was calculated to be 84.4% (95% CI: 74.4–90.4%). Moreover, compared to the blank-control group, the time from the SARS-CoV-2 negative to the positive COVID-19 conversion was significantly longer in the AG86 treatment group (mean time: 3.4 days vs 2.6 days, p = 0.019). In the secondary end-point analysis, the A8G6 nasal treatment had no effects on the viral load at baseline SARS-CoV-2 RT-PCR positivity and the time of the negative COVID-19 conversion. Finally, except for 5 participants (3.1%) with general adverse effects, we did not observe any severe adverse effects related to the A8G6 treatment. In this study, the intranasal spray AG86 antibody cocktail showed potent efficacy for prevention of SARS-CoV-2 infection in close contacts of COVID-19 patients.

Analysis on infection risk in secondary close contacts of COVID-19 patients

Objective: To study the infection rate of secondary close contacts of COVID-19 patients, and assess the infection risk in the contacts. Methods: COVID-19 patients' close contacts (with a clear exposure time to index case) with negative nucleic acid test results and secondary close contacts were surveyed in continuous isolation and medical observation in this prospective study. The dynamic nucleic acid test results of the close contacts and secondary contacts of COVID-19 patients were collected to assess their risk of infection. Results: A total of 4 533 close contacts were surveyed, in whom 14 were confirmed as COVID-19 patients with overall secondary attack rate of 0.31%, and 4 201 secondary contacts were tracked, in whom no subsequent infections occurred. Conclusion: Close contacts of COVID-19 patients entered in centralized isolation for medical observation with negative nucleic acid tese results,the secondary close contacts of COVID-19 patients have no risk of infection.

Using CONTAM to design ventilation strategy of negative pressure isolation ward considering different height of door gaps

Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants, typically by creating active air infiltration through the difference between supply and exhaust air volumes. The door gap is the channel of air flow between rooms, so its height has an important influence on the pressure difference and infiltration air volume of the room. There is still a lack of research on setting reasonable ventilation strategies according to the different heights of door gaps at different positions in the building. In this study, model of a set of isolation wards was established and analyzed using the multi-zone simulation software CONTAM, and the ventilation strategies with different heights of door gaps were applied to the actual infection diseases department. The results show that in a building with ventilation system divided by functional area, the difference in the height of the door gaps requires different active infiltration air volumes. Pressure fluctuations in the medical and patient corridors are greater than in other rooms. The significance of this study is to understand the active infiltration of air to guide the design and operation of ventilation systems in infectious disease hospitals or building remodeled to isolate close contacts of COVID-19 patients. It is also instructive for the design of pressure gradients in clean workshops, biological laboratories, and other similar buildings.

Neutralizing antibody responses in asymptomatic close contacts of COVID-19 patients and in asymptomatic healthcare workers

The identification of novel antibodies that could neutralize SARS-CoV-2 is one of the novel approaches to use in combating COVID-19. This study aimed to explore the level of neutralizing antibodies (NAbs) in asymptomatic close contacts of COVID-19 patients and asymptomatic healthcare workers. In vitro qualitative detection of serum antibodies of participants from both populations was done using an anti-SARS-CoV-2 immunoassay. The study included 107 participants, of which 59.8% were healthcare workers and 40.2% were family contacts of confirmed COVID-19 cases. Their median age was 22 years. The percentage of positivity and median titer for NAbs were significantly higher among family contacts than mong healthcare workers (P = 0.013 and < 0.001, respectively). We also measured C-reactive protein (CRP) levels and the median value of CRP was significantly higher in the family members who had been in contact with COVID-19 patients than in healthcare workers (P < 0.001). In the family contact group, there was a significant negative correlation between the absolute lymphocyte count and CRP (r = -0.409, P = 0.034). There was no significant correlation between neutralizing antibody titers and either CRP or absolute lymphocyte count (P > 0.05 for both). In conclusion, the indication of elevated NAb titers in asymptomatic family contacts could help lay the groundwork for further studies to explore the potential utility of these antibodies to provide future immunity from infection within a family as well as for potential use in general during passive antibody therapies for COVID-19 patients.

Analysis on infectivity of COVID-19 patients before and after last negative nucleic acid test

Objective: To investigate the infection rate in close contacts of COVID-19 patients before and after the last negative nucleic acid test, evaluate the effect of dynamic nucleic acid test in determining the infectivity of COVID-19 patients. Methods: Dynamic nucleic acid test results of COVID-19 cases were collected in a retrospective cohort study. COVID-19 cases with negative nucleic acid test results before their first positive nucleic acid tests were selected as study subjects. Close contacts of the index cases and the secondary close contacts were kept isolation for medical observation to assess their risk of infection. Results: This study included 89 confirmed cases from two local COVID-19 epidemics in Ningbo. A total of 5 609 close contacts were surveyed, the overall infection rate was 0.20%. No close contacts of the COVID-19 cases before the last negative nucleic acid test were infected, and the infection rate in the close contacts of the COVID-19 cases after the last negative nucleic acid test was 1.33%, all of these close contacts lived together with the index cases. No secondary close contacts were infected. Conclusion: COVID-19 patient becomes infectious after the last nucleic acid is negative, and has no infectivity before the last nucleic acid negative.

Mental health status and quality of life in close contacts of COVID-19 patients in the post-COVID-19 era: a comparative study

Close contacts of those with COVID-19 (CC) may experience distress and long-lasting mental health effects. However, the mental health status and quality of life (QOL) in CC have not been adequately examined. This study examined the mental health status and QOL in CC during the post-COVID-19 period. This cross-sectional study comprised 1169 CC and 1290 who were non-close contacts (non-CC). Demographic data were collected; depression, fatigue, post-traumatic stress symptoms (PTSS) and QOL were assessed using the Patient Health Questionnaire - 9 items (PHQ-9), fatigue numeric rating scale, Post-Traumatic Stress Disorder Checklist - 17 items (PCL-17), and the World Health Organization Quality of Life Questionnaire - brief version (WHOQOL-BREF), respectively. Analysis of covariance was used to compare depressive symptoms, QOL, fatigue, and PTSS between the CC and non-CC groups. Multiple logistic regression analyses were performed to determine the independent correlates for depression, fatigue, PTSS, and QOL in the CC group. Compared to the non-CC group, the CC group reported significantly more severe depression (F(1, 2458) = 5.58, p = 0.018) and fatigue (F(1, 2458) = 9.22, p = 0.002) in the post-COVID-19 period. No significant differences in PTSS and QOL between the CC and non-CC groups were found (F(1, 2458) = 2.93, p = 0.087 for PTSS; F(1, 2458) = 3.45, p = 0.064 for QOL). In the CC group, younger age, financial loss due to COVID-19, and perception of poor or fair health status were significantly associated with depression and fatigue, while frequent use of mass media was significantly associated with fatigue. In conclusion, close contacts of COVID-19 patients experienced high levels of depression and fatigue in the post-COVID-19 period. Due to the negative effects of depression and fatigue on daily functioning, early detection and timely interventions should be provided to this neglected population.

The Association between Wearing a Mask and COVID-19.

With the widespread and increasing number of cases of Coronavirus Disease (2019) globally, countries have been taking preventive measures against this pandemic. However, there is no universal agreement across cultures on whether wearing face masks are an effective physical intervention against disease transmission. We investigated the relationship between mask wearing and COVID-19 among close contacts of COVID-19 patients in the Hiroshima Prefecture, Japan. In the Hiroshima Prefecture, a COVID-19 form adapted from the reporting form, “Japanese Surveillance in Post-Extreme Emergencies and Disasters”, was developed to collect data from COVID-19 patients’ close contacts under active epidemiological surveillance at Public Health Centers. The relative risk of COVID-19 for mask users versus non-mask users was calculated. A total of 820 interviewees were included in the analysis and 53.3% of them responded that they wore masks. Non-mask users were infected at a rate of 16.4%, while mask users were infected at a rate of 7.1%. Those who wore masks were infected at a rate of 0.4 times that of those who did not wear masks. (RR = 0.4, 95%CI = 0.3–0.6; Adjusted RR = 0.6, 95%CI = 0.3–0.9). These findings implied that COVID-19 could be avoided to a certain degree by wearing a mask.

Transmission of COVID-19 and its Determinants among Close Contacts of COVID-19 Patients Running title.

Background: This study aimed to determine the secondary attack rate (SAR) and its determinants to describe the clinical features and epidemiological aspects of patients and determine the risk factors of COVID-19 among household contacts in Hamadan Province, west of Iran. Study design: A cohort study. Methods: In this cohort study, a total of 323 index cases and 989 related close contacts ages more than 15 years old (family members, relatives, and co-workers) were enrolled using a manual contact tracing approach, and all participants were tested by reverse transcription polymerase chain reaction test. In this research, the frequency of symptoms was assessed, the SAR among contacts of index cases was calculated, and the risk factors of COVID-19 were evaluated by the logistic regression model. Results: The secondary attack rate for total household members of index cases was estimated at 31.7% (95% CI: 28.8-34.7). It was found that among household contacts, the highest SARs were related to spouses 47.1% (95% CI: 38.7-55.7) and grandparents/parents 39.3% (95% CI: 29.4, 49.9) of index cases, who had also higher risks to become secondary cases (adjusted odds ratio [OR]=2.98, 95% CI: 1.31-6.75 and adjusted OR=2.76, 95% CI: 1.18-6.44, respectively). Considering the occupation of contacts, unemployed and retired people and housewives were most susceptible for transmission of COVID-19. It was revealed that cough was the most prevalent symptom among index and secondary cases. Conclusions: Our findings indicated that spouses and grandparents/parents of index cases were the most susceptible individuals for COVID-19 transmission. Prolonged exposure with index case before COVID-19 diagnosis raised the chance of infection among secondary cases.

Evaluation of a rapid antigen test (Panbio™ COVID-19 Ag rapid test device) for SARS-CoV-2 detection in asymptomatic close contacts of COVID-19 patients

ObjectivesThere is limited information on the performance of rapid antigen detection (RAD) tests to identify SARS-CoV-2-infected asymptomatic individuals. In this field study, we evaluated the Panbio™ COVID-19 Ag Rapid Test Device (Abbott Diagnostics, Jena, Germany) for this purpose. MethodsA total of 634 individuals (355 female; median age, 37 years; range, 9–87) were enrolled. Two nasopharyngeal swabs were collected from household (n = 338) and non-household contacts (n = 296) of COVID-19 cases. RAD testing was carried out at the point of care. The RT-PCR test used was the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, MA, USA). ResultsHousehold contacts were tested at a median of 2 days (range, 1–7) after diagnosis of the index case, whereas non-household contacts (n = 296) were tested at a median of 6 days (range, 1–7) after exposure. In total, 79 individuals (12.4%) tested positive by RT-PCR, of whom 38 (48.1%) yielded positive RAD results. The overall sensitivity and specificity of the RAD test was 48.1% (95% CI 37.4–58.9) and 100% (95% CI 99.3–100), respectively. Sensitivity was higher in household (50.8%; 95% CI 38.9–62.5) than in non-household (35.7%; 95% CI 16.3–61.2%) contacts. Individuals testing positive by RAD test were more likely (p < 0.001) to become symptomatic than their negative counterparts. DiscussionThe Panbio test displays low sensitivity in asymptomatic close contacts of COVID-19 patients, particularly in non-household contacts. Nonetheless, establishing the optimal timing for upper respiratory tract collection in this group seems imperative to pinpoint test sensitivity.

Seroprevalence of SARS-CoV-2-Specific Antibodies among Quarantined Close Contacts of COVID-19 Patients, Faroe Islands, 2020.

Close contacts of coronavirus disease (COVID-19) patients are at high risk for severe acute respiratory syndrome 2 (SARS-CoV-2) infection. We assessed the seroprevalence of SARS-CoV-2–specific antibodies among quarantined close contacts of COVID-19 patients in the Faroe Islands. We invited quarantined close contacts of COVID-19 index patients identified during March 3–April 22, 2020, to participate in this study; 584 (81%) contacts consented and underwent serologic testing. Among the 584 participants, 32 (5.5%) were seropositive for total antibody against SARS-CoV-2. Household and young or elderly contacts had higher risk for seropositivity than other contacts. We found a secondary attack rate of 19.2%. Seroprevalence among close contacts was almost 10-fold higher than among the general population of the Faroe Islands. Regularly testing household close contacts of COVID-19 patients might help track the transmission of SARS-CoV-2.

Research on the Protection Countermeasures for Asymptomatic Patients in COVID-19

Objective: To analyze the problems of protection COVID-19 asymptomatic infected patients, so as to ensure the safety of medical staff working in the epidemic and avoid the second outbreak. Methods: Through the analysis of main symptoms of the COVID-19 asymptomatic infected patients. Know the problems that if it is contagious, infectious strength, and the infection route etc. And take some measures such as launching medical observation for the close contacts of COVID-19 patients, investigating into epidemiology of cluster epidemic, active detection of exposed populations during the process of tracing the source of infection patients etc. to find asymptomatic infected patients. The prevention and control of asymptomatic infected persons should be strengthened by further improving the prevention and control program, increasing screening and monitoring, strengthening management and treatment, and strengthening mass prevention and control. Results: Through this method, COVID-19 asymptomatic infected patients can be detected as early as possible, and its effective prevention and control. Conclusion: The analysis of the protection problem of COVID-19 asymptomatic infector has important guiding significance to the protection of medical staff and individuals in the epidemic treatment.

Risk Factors, Epidemiological and Clinical Outcome of Close Contacts of COVID-19 Cases in a Tertiary Hospital in Southern India

Introduction: The knowledge of epidemiologic characteristics and transmission dynamics of a novel pathogen, such as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) among close contacts can help in planning and development of effective control policies in different parts of the world. Aim: To assess the epidemiological and clinical outcome of close contacts of Coronavirus Disease (COVID-2019) cases admitted in a tertiary COVID hospital and to assess the role of risk factors in predicting the epidemiological outcome of these contacts. Materials and Methods: The current retrospective cohort study was conducted among 1286 close contacts of COVID-19 patients admitted to Government Medical College, Thrissur, Kerala. The data collection was done by a semi-structured telephonic interview by the contact tracing team. The questions included the type of exposure to the index case, symptoms if any, date of last exposure with COVID-19 positive patients, and final COVID-19 status of the contact at the end of 14 days. The association of risk factors of COVID-19 positivity was done using binary logistic regression. Results: Proportion of close contacts of COVID-19 who developed the disease was 24.2% (21.87-26.52%). The mean incubation period was found to be 4.22 days (C.I-3.71-4.65). The serial interval mean was found to be 5.24 days (C.I 4.764-5.716). The proportion of household contacts of COVID-19 cases who developed the disease was found to be 26% (C.I-23%-29%). The majority (52.4%) of infections among contacts were asymptomatic. Most common symptom among the COVID-19 positive was fever (32.8%) followed by cough (16.1%). The most common risk factors of infection among primary close contacts were sharing the same room (adjusted odds ratio-2.394) and common use of fomites (adjusted odds ratio-1.953) while use of a mask was found to be protective (adjusted odds ratio-0.570). Significant factors associated with the type of contact with infection were workplace-related contact (adjusted odds ratio-6.629), household contact (adjusted odds ratio-4.856), and travel-related contact (adjusted odds ratio-2.899). Conclusion:The study concludes important risk factors of transmission among close contacts of COVID-19 as being in a household, workplace and travel related contact where the use of mask was found to be protective. The study also concludes that most of the COVID-19 infections in close contacts are asymptomatic.

Retrospective study identifies infection related risk factors in close contacts during COVID-19 epidemic

ObjectivesThis study aimed to compare the risk of infection of children with that of adults and to explore risk factors of infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by following up close contacts of COVID-19 patients. MethodThe retrospective cohort study was performed among close contacts of index cases diagnosed with COVID-19 in Guangzhou, China. Demographic characteristics, clinical symptoms and exposure information were extracted. Logistic regression analysis was employed to explore the risk factors. The restricted cubic spline was conducted to examine to the dose-response relationship between age and SARS-CoV-2 infection. ResultsThe secondary attack rate (SAR) was 4.4% in 1,344 close contacts. The group of household contacts (17.2%) had the highest SAR. The rare-frequency contact (p < 0.001) and moderate-frequency contact (p < 0.001) were associated with lower risk of infection. Exposure to index cases with dry cough symptoms was associated with infection in close contacts (p = 0.004). Compared with children, adults had a significantly increased risk of infection (p = 0.014). There is a linear positive correlation between age and infection (p = 0.001). ConclusionsChildren are probably less susceptible to COVID-19. Close contacts with frequent contact with patients and those exposed to patients with cough symptoms are associated with an increased risk of infection.

Retrospective Analysis of COVID-19 Outbreak Caused by Administrative Actions of Wuhan Authorities: Mistakes Should Be Avoided in Other Country

Background: In early December 2019 the first COVID-19 case appeared in Wuhan, China, and then turned into a nationwide epidemic one month later. Besides Wuhan the epidemic situation relieved rapidly soon after the central government of China intervene. The infection rate of Wuhan's medical staff was higher than national average. Officials of central government claimed that they did not have precise assessment about the path of potential infection on February 14. We chose to stay in Wuhan to investigate why the outbreak occurred. Methods: With data post by the National Health committee of China, we estimate the basic reproductive number R 0 of COVID-19 in Wuhan and the number of possible COVID-19 infections through the susceptible-exposed-infectious-asymptomatic-recovered (SEIAR) model. We compared the daily new cases of the outbreak in Hubei province (excluding Wuhan), Zhejiang, Guangdong and Henan province with Wuhan until February 17, 2020, and estimated the impact of administrative actions of the Wuhan authorities in the early stages of the epidemic. Findings: By fitting the number of confirmed cases in Wuhan from January 27 to February 10, 2020, we estimated that R 0 =2·88, the number of cases on January 21 was 1199 cases. The number of new cases in Wuhan had increased at a median rate of 1548·0 cases (IQR 928·8-1882·3) next 22 single day since January 27, other areas decline gradually several days later. The administrative actions of Wuhan authorities increased the close contacts of COVID-19 patients, provided new routes for transmission of the COVID-19 outbreak, and medical staffs were put in danger of infection by Wuhan authorities. Interpretation: The Wuhan authorities restricted citizens' freedom of expression, prevent Dr.Li from warning citizen and medical staff about infectivity of COVID-19. The administrative actions of Wuhan authorities artificially creating hospital outpatient cross-infection and additional close contacts. The influence of authorities infringe upon human rights on epidemic prevention need special research by future studies. Funding Statement: No funding. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The authors stated that this research is based on the public announcement of the epidemic situation by the State Council of the PRC and other government-published data. It is a statutory procedure for open government affairs, and therefore does not require the approval of an institutional review committee.

WITHDRAWN: Potential false-positive rate among the 'asymptomatic infected individuals' in close contacts of COVID-19 patients

Editor office’s response for Ahead of Print article withdrawn The article “Potential false-positive rate among the ‘asymptomatic infected individuals’ in close contacts of COVID-19 patients” was under strong discussion after pre-published. Questions from the readers mainly focused on the article’s results and conclusions were depended on theoretical deduction, but not the field epidemiology data and further researches were needed to prove the current theory. Based on previous discussions, the article was decided to be offline by the editorial board from the pre-publish lists. Objective: As the prevention and control of COVID-19continues to advance, the active nucleic acid test screening in the close contacts of the patients has been carrying out in many parts of China. However, the false-positive rate of positive results in the screening has not been reported up to now. Buttoclearifythefalse-positiverateduringscreeningisimportantinCOVID-19controlandprevention. Methods: Point values and reasonable ranges of the indicators which impact the false-positive rate of positive results were estimated based on the information available to us at present. The false-positive rate of positive results in the active screening was deduced, and univariate and multivariate-probabilistic sensitivity analyses were performed to understand the robustness of the findings. Results: When the infection rate of the close contacts and the sensitivity and specificity of reported results were taken as the point estimates, the positive predictive value of the active screening was only 19.67%, in contrast, the false-positive rate of positive results was 80.33%. The multivariate-probabilistic sensitivity analysis results supported the base-case findings, with a 75% probability for the false-positive rate of positive results over 47%. Conclusions: In the close contacts of COVID-19 patients, nearly half or even more of the 'asymptomatic infected individuals' reported in the active nucleic acid test screening might be false positives.

Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China.

Previous studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease (COVID-19) and the evidence of person-to-person transmission. Limited data are available for asymptomatic infections. This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers. Epidemiological investigations were conducted among all close contacts of COVID-19 patients (or suspected patients) in Nanjing, Jiangsu Province, China, from Jan 28 to Feb 9, 2020, both in clinic and in community. Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples. Their clinical records, laboratory assessments, and chest CT scans were reviewed. As a result, none of the 24 asymptomatic cases presented any obvious symptoms while nucleic acid screening. Five cases (20.8%) developed symptoms (fever, cough, fatigue, etc.) during hospitalization. Twelve (50.0%) cases showed typical CT images of ground-glass chest and 5 (20.8%) presented stripe shadowing in the lungs. The remaining 7 (29.2%) cases showed normal CT image and had no symptoms during hospitalization. These 7 cases were younger (median age: 14.0 years; P=0.012) than the rest. None of the 24 cases developed severe COVID-19 pneumonia or died. The median communicable period, defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests, was 9.5 days (up to 21 days among the 24 asymptomatic cases). Through epidemiological investigation, we observed a typical asymptomatic transmission to the cohabiting family members, which even caused severe COVID-19 pneumonia. Overall, the asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization. However, the communicable period could be up to three weeks and the communicated patients could develop severe illness. These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests. Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged.Electronic Supplementary MaterialSupplementary material is available for this article at 10.1007/s11427-020-1661-4 and is accessible for authorized users.