Household Transmission Of COVID-19 Research Articles

Development and use of a directed acyclic graph (DAG) for conceptual framework and study protocol development exploring relationships between dwelling characteristics and household transmission of COVID-19 – England, 2020

BackgroundHousehold settings are high risk for COVID-19 transmission. Understanding transmission factors associated with environmental dwelling characteristics is important in informing public health and building design recommendations. We aimed to develop a directed acyclic graph (DAG) to inform a novel analytical study examining the effect of dwelling environmental characteristics on household transmission of COVID-19. MethodsKey demographic, behavioural and environmental dwelling characteristics were identified by a multidisciplinary team. Using the DAG to visually display risk factors, and using expert knowledge of available datasets we reached a consensus on the factors included and directionality of relationships to build the final conceptual framework. Factors were displayed as nodes and relationships as pathways. ResultsOf 34 potential factors, 16 were included in the DAG, with 13 causal and three biasing pathways. Three variables were not measurable using retrospective datasets. The DAG enabled us to select data sources for the pilot study period and to inform the analysis plan. Key exposure nodes were energy efficiency or dwelling age; dwelling type or number of storeys; and dwelling size. We determined direct and proxy confounders which we could adjust for, potential interactions terms we could test in model building, and co-linear variables to omit in the same model. ConclusionsThe DAG helped identify key variables and datasets. It prioritised key nodes and pathways to formalise complex relationships between variables. It was pivotal in identifying unobserved variables, confounders, co-linearity and potential interactions. It has supported data selection and design of a retrospective pilot study analysis plan.

Cohort profile: evaluation of immune response and household transmission of SARS-CoV-2 in Costa Rica: the RESPIRA study

PurposeThe RESPIRA cohort aims to describe the nature, magnitude, time course and efficacy of the immune response to SARS-CoV-2 infection and vaccination, population prevalence, and household transmission of COVID-19.ParticipantsFrom November...

Household transmission of COVID-19 according to index case: children, parents, and healthcare workers.

The first SARS-CoV-2 intrafamilial transmission was investigated in China. We evaluated the dynamics of SARS-CoV-2 transmission in 242 individuals from 60 family clusters, including 30 healthcare workers (HCW) and 30 patients, in São Paulo city. Sixty index cases with COVID-19 were selected, being 30 HCW index cases from Hospital São Paulo (HSP) and its 93 household contacts and 30 index case patients from Hospital Infantil Sabará (HIS) and its 89 household contacts. Asymptomatic and symptomatic individuals participating were tested for COVID-19. The secondary attack rates in the family clusters of HCW and HIS patients were 37.63% and 68.54%, respectively. Considering all households, the transmission from adults to children was 55.4%, while the transmission from children to children was 37.5%. Children were more infected if the index case was an adult, suggesting that children were less competent to transmit. The average time for a household to be COVID-19 positive was 4 and 3 days for HCW and HIS patients. Although HCW have a higher risk of infection and social vulnerability, the secondary attack rate was lower than that observed for HIS patients, possibly because HCW are more aware of transmission risks than the general community.

Preventing within household transmission of Covid-19: is the provision of accommodation to support self-isolation feasible and acceptable?

BackgroundWithin-household transmission of Covid-19 is responsible for a significant number of infections. Efforts to protect at risk communities are needed. This study explored the acceptability of offering accommodation to support self-isolation among at risk populations, to prevent transmission of Covid-19 within vulnerable households.MethodsMixed methods design structured in two phases. Phase 1: Survey of 545 individuals who had provided consent to be contacted about ongoing research projects into infection control. Phase 2: Semi-structured interviews with 19 participants from ethnic minority and low income communities.ResultsMany survey and interview participants viewed the provision of accommodation as important and necessary in certain contexts. Of the 110 survey respondents, 85 (77%) said that they were not able to isolate at home. Among this group, 24 (28%) said they would accept accommodation and 23 (27%) said that they would probably accept. Of those unable to isolate at home, and at high risk if they caught the virus (N = 36) or living with someone at high risk (N 18), 19 (35%) said that they would accept, and 12 (22%) said they would probably accept accommodation.Factors influencing uptake of accommodation included perceived 1) household vulnerability 2) virus exposure and 3) lack of isolation at home options. Barriers to accepting the accommodation offer included 1) able to isolate at home 2) wanting to be with family 3) caring responsibilities 4) mental wellbeing concerns 5) concerns about moving when ill and 6) infection control concerns. Participants raised issues that should be addressed before accommodation is offered, including questions regarding who should use temporary accommodation and when, and how infection control in temporary accommodation would be managed.ConclusionThe provision of accommodation to prevent within household transmission of Covid-19 is viewed as acceptable, feasible and necessary by some people who are concerned about infection transmission in the home and are unable to self-isolate or socially distance at home. Different households will have different requirements, e.g., those with caring responsibilities, and to overcome these challenges additional support may be needed for the provision of accommodation to be feasible to those who could benefit most.

Household transmission of COVID-19 among the earliest cases in Antananarivo, Madagascar.

BackgroundHouseholds are among the highest risk for the transmission of SARS‐CoV‐2. In sub‐Saharan Africa, very few studies have described household transmission during the COVID‐19 pandemic. Our work aimed to describe the epidemiologic parameters and analyze the secondary attack rate (SAR) in Antananarivo, Madagascar, following the introduction of SARS‐CoV‐2 in the country in March 2020.MethodsA prospective case‐ascertained study of all identified close contacts of laboratory‐confirmed COVID‐19 infections was conducted in Antananarivo from March to June 2020. Cases and household contacts were followed for 21 days. We estimated epidemic parameters of disease transmission by fitting parametric distributions based on infector‐infected paired data. We assessed factors influencing transmission risk by analyzing the SAR.FindingsOverall, we included 96 index cases and 179 household contacts. Adjusted with the best‐fit normal distribution, the incubation period was 4.1 days (95% CI 0.7–7.5]). The serial interval was 6.0 days (95% CI [2.4–9.6]) after adjusting with the best‐fit Weibull distribution. On average, each index case infected 1.6 family members (95%CI [0.9–2.3]). The mean SAR among close contacts was 38.8% (95% CI [19.5–58.2]) with the best‐fit gamma distribution. Contacts older than 35 years old were more likely to be infected, and the highest SAR was found among them.ConclusionThe results of our study provide key insights into the epidemiology of the first wave of SARS‐CoV‐2 in Madagascar. High rates of household transmission were found in Antananarivo, emphasizing the need for preventive measures to reduce community transmission.

Use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers associated with lower risk of COVID-19 in household contacts.

BackgroundUse of angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) has been hypothesized to affect COVID-19 risk.ObjectiveTo examine the association between use of ACEI/ARB and household transmission of COVID-19.MethodsWe conducted a modified cohort study of household contacts of patients who tested positive for COVID-19 between March 4 and May 17, 2020 in a large Northeast US health system. Household members were identified by geocoding and full address matching with exclusion of addresses with >10 matched residents or known congregate living functions. Medication use, clinical conditions and sociodemographic characteristics were obtained from electronic medical record (EMR) data on cohort entry. Cohort members were followed for at least one month after exposure to determine who tested positive for SARS-CoV-2. Mixed effects logistic regression and propensity score analyses were used to assess adjusted associations between medication use and testing positive.Results1,499 of the 9,101 household contacts were taking an ACEI or an ARB. Probability of COVID-19 diagnosis during the study period was slightly higher among ACEI/ARB users in unadjusted analyses. However, ACEI/ARB users were older and more likely to have clinical comorbidities so that use of ACEI/ARB was associated with a decreased risk of being diagnosed with COVID-19 in mixed effect models (OR 0.60, 95% CI 0.44–0.81) or propensity score analyses (predicted probability 18.6% in ACEI/ARB users vs. 24.5% in non-users, p = 0.03). These associations were similar within age and comorbidity subgroups, including patients with documented hypertension, diabetes or cardiovascular disease, as well as when including other medications in the models.ConclusionsIn this observational study of household transmission, use of ACEIs or ARBs was associated with a decreased risk of being diagnosed with COVID-19. While causality cannot be inferred from these observational data, our results support current recommendations to continue ACEI/ARB in individuals at risk of COVID-19 exposure.

485. Title: The Porous Boundaries Between Communities and Correctional Facilities: The Introduction of a Medical Recovery Site Resulting in Reduced COVID-19 Household Transmission Tied to Recently Incarcerated Individuals

BackgroundIn April 2020, a COVID-19 outbreak at a rural, resource-limited Department of Corrections on a Native American reservation in Arizona led to multiple epidemiologically linked cases to household contacts of recently incarcerated individuals. We describe the role of a medical recovery site for isolation of recently released inmates with active COVID-19 infection in reducing household transmission of cases tied to the correctional facility.MethodsOn April 16th, an individual was contact traced to the correctional facility and was laboratory-confirmed positive, an asymptomatic index case in the jail. Testing of all inmates continued from April 16th-30th. On April 24th, decarceration began. All inmates released from facility April 24th-April 30th were contact traced for 14 days to monitor for new household cases. On April 30th, the tribe opened a medical recovery site for isolation. After opening, all individuals with active infection agreed to go to site after release.ResultsBetween April 24th-30th, 16 inmates were released from facility, seven were laboratory-confirmed positive. Secondary infections only occurred in households of positives. Of the seven households, four experienced secondary transmission of virus. There were 27 household contacts, six secondary infections (secondary attack rate of 30.0%). There were four hospitalizations and one death, though cause of death was not due to COVID-19 despite incidental finding. After opening of medical recovery site, all individuals with active infection (12 cases) agreed to isolation at site. This intervention resulted in no further epidemiologically linked cases from recently released incarcerated individuals to community.Figure 1: Household Secondary Infections with Epidemiological Links to Previously Incarcerated Inmates Before and After Opening of Medical Recovery Site ConclusionPrior to establishment of a medical recovery site on a Native American reservation, a significant burden of disease in the community was linked to recently incarcerated individuals. After opening, all actively infected individuals agreed to isolation at site, resulting in no further household transmission of COVID-19 from an actively infected recently incarcerated case. This outbreak highlights porous boundaries between correctional facilities and surrounding communities, requiring attention and resources to limit transmission of disease to protect local populations.Disclosures All Authors: No reported disclosures