The Los Angeles County COVID-19 Surveillance Cohort Initiative

Last registered on September 21, 2021

Pre-Trial

Trial Information

General Information

Title
The Los Angeles County COVID-19 Surveillance Cohort Initiative
RCT ID
AEARCTR-0007455
Initial registration date
April 01, 2021
Last updated
September 21, 2021, 5:21 PM EDT

Locations

Primary Investigator

Affiliation
University of Southern California

Other Primary Investigator(s)

PI Affiliation
University of Southern California
PI Affiliation
University of Southern California

Additional Trial Information

Status
On going
Start date
2021-03-22
End date
2022-06-30
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
COVID-19 is the most pressing health and economic crisis facing our country and the world. We have taken unprecedented measures to stall the spread of COVID-19 and the pandemic is affecting the way we live in fundamental ways. We need reliable information on the trajectory of the epidemic to design effective public policy and to gauge whether public health measures to stall the epidemic are having their intended effect. The first overall goal of this study is to recruit a representative cohort of persons in Los Angeles county and offer repeat antibody testing and surveys to this cohort every 2-3 months. Antibody testing will capture the trajectory of the epidemic and surveys will capture how the epidemic is affecting Los Angelenos and risk factors for infection. This information is crucial for guiding policy response .

With the COVID-19 vaccine now being implemented in high-priority groups (front-line health care workers and nursing home residents) and soon to be implemented in stages in other groups, antibody testing will be an important adjunctive tool for prioritizing vaccines. For example, those with potential immunity through natural infection might be last in priority to receive vaccines. Similarly, antibody testing might also be used to study vaccine efficacy. Those who are seropositive after vaccination will have potential immunity. Thus, a second goal of this study is to understand critical behaviors. For example, what is the degree of vaccine hesitancy in various LA County demographic groups? As another example, what is the impact of knowing positive or negative serostatus on individuals’ risk perceptions, risk mitigation behaviors as well as health, social and economic behaviors? With regards to this question, we hypothesize that knowing seropositive status will lead study participants to shift behaviors based on an updated belief that they have immunity. This will lead to reduced stress/anxiety, greater interaction with friends/family, greater economic activity, and reduced risk mitigation behaviors. Similarly, we hypothesize that knowing seronegative status will lead to increases in risk mitigation behaviors, increases in stress/anxiety, less interaction with friends/family, and reduced economic activity. To test these hypotheses, we will randomize participants into 2 groups: those who receive results within 1 week (RAPID Group) and those who receive results after 3 weeks (NORMAL Group). We will conduct a survey 2 weeks after testing when RAPID Group members know their serostatus and NORMAL Group members do not. Comparing behaviors in the RAPID group versus the NORMAL group, stratified by serostatus, will allow us to estimate the causal effects of serostatus knowledge on COVID-19-realted attitudes, beliefs and behaviors.
External Link(s)

Registration Citation

Citation
Hu, Howard, Chun Nok Lam and Neeraj Sood. 2021. "The Los Angeles County COVID-19 Surveillance Cohort Initiative." AEA RCT Registry. September 21. https://doi.org/10.1257/rct.7455-1.1
Experimental Details

Interventions

Intervention(s)
This study will offer repeat antibody testing to the cohort every 2-3 months. For serological testing, we plan to collect a small volume of blood using a self-administered small volume blood collection device. We will use an FDA EUA antibody test to conduct the antibody testing. The testing will be performed at a CLIA (Clinical Laboratory Improvement Amendment) approved laboratory at our institution. Participants will arrive at their nearest testing location on their selected date and the sample will be drawn while they are in car. Participants are randomized to one of two groups: 1) those who receive results within 1 week (RAPID Group) or 2) those who receive results after 3 weeks (NORMAL Group).
Intervention Start Date
2021-04-09
Intervention End Date
2021-05-16

Primary Outcomes

Primary Outcomes (end points)
The primary research objectives are to track the seroprevalence of COVID-19 antibodies in a representative sample of people living in Los Angeles County and to understand the impact of knowing serostatus on health, social and economic behaviors.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
● To describe correlates of seroprevalence such as population density and demographics
● To describe inequities in the burden of COVID-19 by socio-economic status and race/ethnicity, and geography
● To understand the cumulative incidence of both symptomatic and asymptomatic Covid-19 cases in Los Angeles County
● To understand how long SARS-CoV-2 antibodies remain detectable
● To understand behaviors as they may relate to (a) risk factors for COVID-19 infection and/or propagating COVID-19 infections and (b) attitudes with respect to hesitancy towards taking the COVID-19 vaccine.
● To test hypotheses related to behaviors that may result from understanding COVID-19 antibody status.
● To establish a cohort as a resource for additional research of critical importance to controlling the COVID-19 pandemic
● To use estimates of seroprevalence to project case-fatality rates among those who have been infected with SARS-CoV-2


Secondary Outcomes (explanation)

Experimental Design

Experimental Design
One of the study goals is to understand critical behaviors. For example, what is the degree of vaccine hesitancy in various LA County demographic groups? As another example, what is the impact of knowing positive or negative serostatus on individuals’ risk perceptions, risk mitigation behaviors as well as health, social and economic behaviors? With regards to this question, we hypothesize that knowing seropositive status will lead study participants to shift behaviors based on an updated belief that they have immunity. This will lead to reduced stress/anxiety, greater interaction with friends/family, greater economic activity, and reduced risk mitigation behaviors. Similarly, we hypothesize that knowing seronegative status will lead to increases in risk mitigation behaviors, increases in stress/anxiety, less interaction with friends/family, and reduced economic activity. To test these hypotheses, we will randomize participants into 2 groups: those who receive results within 1 week (RAPID Group) and those who receive results after 3 weeks (NORMAL Group). We will conduct a survey 2 weeks after testing when RAPID Group members know their serostatus and NORMAL Group members do not. Comparing behaviors in the RAPID group versus the NORMAL group, stratified by serostatus, will allow us to estimate the causal effects of serostatus knowledge on COVID-19-realted attitudes, beliefs and behaviors.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
2000 adults, 1000 children
Sample size: planned number of observations
2000 adults, 1000 children
Sample size (or number of clusters) by treatment arms
Only adults will be randomized: 1000 treatment, 1000 control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
Public Health, Ambulatory Care Network and Health Services Administration Institutional Review Board
IRB Approval Date
2021-02-05
IRB Approval Number
2021-01-919