Index Individuals in SARS-CoV-2 Prevention Research Studies (COVID-19 Index Individuals Companion Study) (IICov19PRS)

Within households, the incidence of SARS-CoV-2 is high, but the risk of transmission is characterized by exposure cofactors and transmission mitigation strategies.

Exposure cofactors are defined as cofactors that influence infectiousness of the index individual such as SARS-CoV-2 viral load, SARS-CoV-2 antibodies, and viable virus (as characterized by subgenomic RNA).

Transmission mitigation strategies are defined as modifiable cofactors that influence transmission and currently include physical distancing, social isolation, ventilation, and handwashing.

The continued progression of the pandemic has seen an increase in reports of persistent and/or delayed onset of symptoms and complications in patients well past the acute phase of COVID-19 infection. The prevalence and impacts of these post-acute sequelae of SARS-CoV-2 infection (PASC), which may continue for weeks to months after the initial COVID-19 illness, are not well understood.

Up to approximately 2,000 eligible index individuals who have close contacts (e.g., uninfected household members) in COVID-19 prevention research studies will be invited to participate. Individuals that enroll within two weeks of their diagnosis will be asked to provide a baseline mid-turbinate nasal swab for SARS-CoV-2 testing and complete questionnaires at baseline and on Days 7 and 14. Through these questionnaires, index individuals will report on the clinical course of their illness and share information about their household environment, including potential exposures there-in and any COVID-19 transmission mitigation strategies implemented (whether intentional or as part of standard home routines). Individuals that enroll more than two weeks after being diagnosed will be asked to provide a mid-turbinate nasal swab for SARS-CoV-2 testing and to complete a questionnaire reporting retrospectively on their COVID-19 illness and household environment. These individuals will also complete a questionnaire reporting on the persistence and/or delayed onset of symptoms and complications that they associate with their COVID-19 illness. Enrolled index individuals will also be invited to participate in the SARS-CoV-2 Antibody Sub-study and provide a dried blood spot specimen (at baseline) for antibody testing.

Working closely with prevention research studies, we propose to characterize the index individual level cofactors for SARS-CoV-2 transmission.

Each contact between an index individual and close contact is the unit of analysis for the research study.

The ascertainment of SARS-CoV-2 status among contacts/household members will be done through the parent prevention research study, e.g., through an existing clinical trials agreement with the CoVPN 3502/R 10933-10987-COV-2069 study.h

Across these studies, the investigators aim to assess:

• Prevalence and incidence of SARS-CoV-2 infection in the close contacts.
• Reported SARS-CoV-2 transmission mitigation strategies and exposures as assessed in the index individuals (3502-01) and household contact protocols (e.g., 3502) and the correlation between them.
• Association between the index individual SARS-CoV-2 viral load and subgenomic RNA and infection in the contact participant.
• Association of the duration of symptomatic COVID-19 in the index individual on the risk of SARS-CoV-2 transmission.
• Association of SARS-CoV-2 viral genotype in index individual to related SARS-CoV-2 genotype infection in the contact participant
• Post-acute sequelae of SARS-CoV-2 (PASC) infection in individuals that are weeks to months past their initial SARS-CoV-2 infection.

With these combined household data, effective, modifiable cofactors for household transmission can be identified to inform future post-exposure interventions. With the inclusion of data related to viral and host exposure cofactors, the investigators can increase the precision of predictive models of SARS-CoV-2 infection, adjusted for exposure and mitigation strategies. Data collected on PASC will contribute to the characterization of the long term consequences of SARS-CoV-2 infection and Post-acute COVID-19 Syndrome.