SARS-CoV-2 transmission across age groups in France and implications for control.
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ABSTRACT:
SUBMITTER: Tran Kiem C
PROVIDER: S-EPMC8617041 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. Methods We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. Results We estimated that individuals in our study households had a 0.41% (95% CI 0.32%– 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%– 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33–0.52) to avoid continued growth of the pandemic in Utah. Conclusions Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.
| S-EPMC8580228 | biostudies-literature
Project description:ObjectivesSARS-CoV-2 can be transmitted by aerosols, and the ocular surface may be an important route of transmission. Little is known about protective antibody responses to SARS-CoV-2 in tears after infection or vaccination. We analysed the SARS-CoV-2-specific IgG and IgA responses in human tears after either COVID-19 infection or vaccination.MethodsWe measured the antibody responses in 16 subjects with COVID-19 infection for an average of 7 months before, and 15 subjects before and 2 weeks post-Comirnaty (Pfizer-BioNtech) vaccination. Plasma, saliva and basal tears were collected. Eleven pre-pandemic individuals were included as healthy controls.ResultsIgG antibodies to spike and nucleoprotein were detected in tears, saliva and plasma from subjects with prior SARS-CoV-2 infection in comparison with uninfected controls. While receptor-binding domain (RBD)-specific antibodies were detected in plasma, minimal RBD-specific antibodies were detected in tears and saliva. By contrast, high levels of IgG antibodies to spike and RBD, but not nucleoprotein, were induced in tears, saliva and plasma of subjects receiving 2 doses of the Comirnaty vaccine. Increased levels of IgA1 and IgA2 antibodies to SARS-CoV-2 antigens were detected in plasma following infection or vaccination but were unchanged in tears and saliva. Comirnaty vaccination induced high neutralising Abs in the plasma, but limited neutralising antibodies were detected in saliva or tears.ConclusionBoth infection and vaccination induce SARS-CoV-2-specific IgG antibodies in tears. RBD-specific IgG antibodies in tears were induced by vaccination but were not present 7 months post-infection. This suggests the neutralising antibodies may be low in the tears late following infection.
| S-EPMC8559894 | biostudies-literature
Project description:BackgroundFrom March to June 2022, an Omicron BA.2 epidemic occurred in Shanghai. We aimed to better understand the transmission dynamics and identify age-specific transmission characteristics for the epidemic.MethodsData on COVID-19 cases were collected from the Shanghai Municipal Health Commission during the period from 20th February to 1st June. The effective reproductive number (Rt) and transmission distance between cases were calculated. An age-structured SEIR model with social contact patterns was developed to reconstruct the transmission dynamics and evaluate age-specific transmission characteristics. Least square method was used to calibrate the model. Basic reproduction number (R0) was estimated with next generation matrix.ResultsR0 of Omicron variant was 7.9 (95% CI: 7.4 to 8.4). With strict interventions, Rt had dropped quickly from 3.6 (95% CI: 2.7 to 4.7) on 4th March to below 1 on 18th April. The mean transmission distance of the Omicron epidemic in Shanghai was 13.4 km (95% CI: 11.1 to 15.8 km), which was threefold longer compared with that of epidemic caused by the wild-type virus in Wuhan, China. The model estimated that there would have been a total 870,845 (95% CI: 815,400 to 926,289) cases for the epidemic from 20th February to 15th June, and 27.7% (95% CI: 24.4% to 30.9%) cases would have been unascertained. People aged 50-59 years had the highest transmission risk 0.216 (95% CI: 0.210 to 0.222), and the highest secondary attack rate (47.62%, 95% CI: 38.71% to 56.53%).ConclusionsThe Omicron variant spread more quickly and widely than other variants and resulted in about one third cases unascertained for the recent outbreak in Shanghai. Prioritizing isolation and screening of people aged 40-59 might suppress the epidemic more effectively. Routine surveillance among people aged 40-59 years could also provide insight into the stage of the epidemic and the timely detection of new variants.Trial registrationWe did not involve clinical trial.
| S-EPMC10121427 | biostudies-literature
Project description:Dysregulated immune responses contribute to the excessive and uncontrolled inflammation observed in severe COVID-19. However, how immunity to SARS-CoV-2 is induced and regulated remains unclear. Here we uncover a role of the complement system in the induction of innate and adaptive immunity to SARS-CoV-2. Complement rapidly opsonizes SARS-CoV-2 particles via the lectin pathway. Complement-opsonized SARS-CoV-2 efficiently induces type-I interferon and pro-inflammatory cytokine responses via activation of dendritic cells, which are inhibited by antibodies against the complement receptors (CR) 3 and 4. Serum from COVID-19 patients, or monoclonal antibodies against SARS-CoV-2, attenuate innate and adaptive immunity induced by complement-opsonized SARS-CoV-2. Blocking of CD32, the FcγRII antibody receptor of dendritic cells, restores complement-induced immunity. These results suggest that opsonization of SARS-CoV-2 by complement is involved in the induction of innate and adaptive immunity to SARS-CoV-2 in the acute phase of infection. Subsequent antibody responses limit inflammation and restore immune homeostasis. These findings suggest that dysregulation of the complement system and FcγRII signaling may contribute to severe COVID-19.
| S-SCDT-10_1038-S44318-024-00061-0 | biostudies-other
Project description:The COVID-19 pandemic is creating a havoc situation across the globe that modern society has ever seen. Despite of their paramount importance, the transmission routes of SARS-Cov-2 still remain debated among various sectors. Evidences compiled here strongly suggest that the COVID-19 could be transmitted via air in inadequately ventilated environments. Existing experimental data showed that coronavirus survival was negatively impacted by ozone, high temperature and low humidity. Here, regression analysis showed that the spread of SARS-Cov-2 was reduced by increasing ambient ozone concentration level from 48.83 to 94.67 ?g/m3 (p-value = 0.039) and decreasing relative humidity from 23.33 to 82.67% (p-value = 0.002) and temperature from -13.17 to 19 °C) (p-value = 0.003) observed for Chinese cities during Jan-March 2020. Besides using these environmental implications, social distancing and wearing a mask are strongly encouraged to maximize the fight against the COVID-19 airborne transmission. At no other time than now are the scientists in various disciplines around the world badly needed by the society to collectively confront this disastrous pandemic.
| S-EPMC7198171 | biostudies-literature
Project description:ObjectivesThe SARS-CoV-2 epidemic presents a poorly understood epidemiological cycle. We aimed to compare the age and weekly distributions of the five human coronaviruses, including SARS-CoV-2, that circulated in southeastern France.MethodsWe analyzed all available diagnoses of respiratory viruses, including SARS-CoV-2, performed between 09/2013 and 05/2020 at the University Hospital Institute Méditerranée Infection in Marseille, southeastern France.ResultsFor SARS-CoV-2, positive children <15 years of age represented 3.4% (228/6,735) of all positive cases, which is significantly less than for endemic coronaviruses (46.1%; 533/1,156; p < 0.001). Among 10,026 patients tested for SARS-CoV-2 and endemic coronaviruses in 2020, children <15 years represented a significantly lower proportion of all positive cases for SARS-CoV-2 than for endemic coronaviruses [2.2% (24/1,067) vs. 33.5% (149/445), respectively; p < 0.001]. Epidemic curves for endemic coronaviruses and SARS-CoV-2 in 91,722 patients showed comparable bell-shaped distributions with a slight time lag. In contrast, the age distribution of endemic coronaviruses and 14 other respiratory viruses differed significantly compared to that of SARS-CoV-2, which was the only virus to relatively spare children.ConclusionsWe observed for SARS-CoV-2 a temporal distribution resembling that of endemic coronaviruses but an age distribution that relatively spares the youngest subjects, who are those the most exposed to endemic coronaviruses.
| S-EPMC7511210 | biostudies-literature
Project description:Hereby, we report a confirmed case of intrauterine SARS-CoV-2 transmission with rapid placental dysfunction and fetal distress.
| PRJEB40434 | ENA
Project description:BackgroundWe aimed to assess the settings and activities associated with SARS-CoV-2 infection in the context of B.1.617.2 (Delta) variant circulation in France, as well as the protection against symptomatic Delta infection.MethodsIn this nationwide case-control study, cases were SARS-CoV-2 infected adults recruited between 23 May and 13 August 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire and multivariable logistic regression analysis was used to determine the association between acute SARS-CoV-2 infection and recent activity-related exposures, past history of SARS-CoV-2 infection, and COVID-19 vaccination.FindingsWe did not find any differences in the settings and activities associated with Delta versus non-Delta infections and grouped them for subsequent analyses. In multivariable analysis involving 12634 cases (8644 Delta and 3990 non-Delta) and 5560 controls, we found individuals under 40 years and attending bars (aOR:1.9; 95%CI:1.6-2.2) or parties (aOR:3.4; 95%CI:2.8-4.2) to be at increased risk of infection. In those aged 40 years and older, having children attend daycare (aOR:1.9; 95%CI:1.1-3.3), kindergarten (aOR:1.6; 95%CI:1.2-2.1), primary school (aOR:1.4; 95%CI:1.2-1.6) or middle school (aOR:1.3; 95%CI:1.2-1.6) were associated with increased risk of infection. We found strong protection against symptomatic Delta infection for those with prior infection whether it was recent (2-6 months) (95%; 95%CI:90-97) or associated with one dose (85%; 95%CI:78-90) or two doses of mRNA vaccine (96%; 95%CI:87-99). For those without past infection, protection was lower with two doses of mRNA vaccine (67%; 95%CI:63-71).InterpretationIn line with other observational studies, we find reduced vaccine effectiveness against symptomatic Delta infections. The settings and activities at increased risk of infection indicate where efforts to reinforce individual and public health measures need to be concentrated.
| S-EPMC8616730 | biostudies-literature
Project description:BackgroundWe aimed to detect the risk factors for SARS-CoV-2 infection among healthcare workers (HCWs) in 2020 before the vaccination era.MethodsWe surveyed SARS-CoV-2 infection among the HCWs in a hospital through screening for antibody levels and the detection of viral RNA by RT-PCR between May 2020 and December 2020. Occupational and non-occupational potential predictors of disease were surveyed for the HCWs included in this study.ResultsAmong 1925 personnel in the hospital, 1732 were included to the study with a response rate of 90%. The overall infection rate of HCWs was 16.3% at the end of 2020, before vaccinations started. In the multivariate analysis, being janitorial staff (OR: 2.24, CI: 1.21-4.14, p = 0.011), being a medical secretary (OR: 4.17, CI: 2.12-8.18, p < 0.001), having at least one household member with a COVID-19 diagnosis (OR: 8.98, CI: 6.64-12.15, p < 0.001), and number of household members > 3 (OR: 1.67, CI: 1.26-2.22, p < 0.001) were found to be significantly associated with SARS-CoV-2 infection.ConclusionsMedical secretaries and janitorial staff were under increased risk of SARS-CoV-2 infection. The community-hospital gradient can explain the mode of transmission for infection among HCWs. In the setting of this study, community measures were less strict, whereas hospital infection control was adequate and provided necessary personal protective equipment. Increasing risk in larger households and households with diagnosed COVID-19 patient indicates the community-acquired transmission of the infection.
| S-EPMC8395820 | biostudies-literature
Project description:Interventions: Group 1: A qualitative interview study as well as a cross-sectional questionnaire survey is conducted with patients, oncologists and nurses working in the field of oncology (subproject 1). This is complemented by retrospective analysis of quantitative data derived from the registry of colon cancer centres (subproject 2) and data from the statutory health insurance (subproject 3).
Primary outcome(s): Aim: Assessment of ethical and psychosocial challenges in cancer care via semi-structured interviews with stakeholders (oncologists, nurses, patients) between January and July 2021. Assessment of psychosocial burden of oncologists, nurses and patients between February and July 2021 via questionnaires.
patients: Mini-SCL, EORTC QLQ-C30, NCCN Distress Thermometer, FACT-19
oncologists: PHQ-9, PHQ-15, GAD-7, Maslach Burnout Inventory, Moral Distress Thermometer, FACT-19, sociodemographic questionnaire
nurses: PHQ-9, PHQ-15, GAD-7, Maslach Burnout Inventory, Moral Distress Thermometer, FACT-19, BERNCA, sociodemographic questionnaire
Study Design: Allocation: ; Masking: ; Control: ; Assignment: ; Study design purpose: other
| 2439669 | ecrin-mdr-crc