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.