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MedStar Health has been conducting a large scale, multi-site Centers for Disease Control and Prevention (CDC) funded Community Research Partnership (CRP) study, “A Prospective Study of COVID-19 Using Real-Time Syndromic Surveillance, Scheduled At-home Serologic Testing, and Electronic Health Records”. The goal of the study is to determine how much of the population has been exposed to the COVID-19 virus by utilizing daily syndromic surveillance, monthly serologic testing, and electronic health record data. The CDC COVID-19 CRP is an at-home research study to help us better understand the best ways to treat and prevent COVID-19.
The study began in November of 2020 and has gained more than 60,000 participants, over 4.5 million daily symptom updates, received over 150,000 serology results, and collected more than 17 million electronic health record data elements. At MedStar Health, there are 11,095 participants who remain engaged in daily syndromic surveillance. There are 8,538 participants enrolled in monthly serology testing with over 44,000 serology kits distributed. More than 50% of these participants have been participating in monthly serology for at least six months – representing incredible engagement from our community that allows the research team to evaluate antibody development and decay over time.
Preliminary study results show that antibodies are identified at a detectable level around two weeks after natural infection or vaccination and these antibodies take longer to develop in older participants. The results also show that in participants with natural infection, antibodies drop to undetectable levels within two to three months as compared to vaccinated individuals with detectable antibodies lasting at least eight months. For patients who were infected with the SARS-CoV-2 virus, antibody decay is more rapid in participants with no or few symptoms as compared to more significant infection.
For participants who seroconverted (serology results were first negative then positive), 35% reported symptoms in the month prior to seroconversion. Participants with positive serology results reported symptom combinations like congestion and anosmia or ageusia (loss of smell or taste). However, symptom combinations like diarrhea and nausea were strongly associated with negative serology. Cumulative reports of symptoms logged by participants in their daily symptom surveillance showed that self-reported symptoms persist weeks after seroconversion with runny nose, muscle pain, headache, fever, and fatigue being commonly reported.
Significant work of the study team is focusing on vaccine effectiveness (with a research letter to be published in the New England Journal of Medicine on October 6, 2021). Looking at both the Pfizer-BioNTech and Moderna RNA vaccines in a case control evaluation, infections were significantly higher in unvaccinated than vaccinated participants, with effectiveness in preventing over 90% of self-reported positive tests for COVID-19. The study team is currently analyzing breakthrough infections and sharing findings to the CDC highlighting the need for ongoing surveillance, screening for novel variants, and possible booster vaccination programs.
As part of daily symptom surveillance, participants self-report symptoms, healthcare utilization, COVID-19 exposures, and public health behaviors including mask use and social distancing. The research team found that mask use is higher in vaccinated participants than unvaccinated, regardless of the month of their first vaccination dose. Mask use remained relatively stable from December 2020 through April 2021 and declined in all groups beginning in mid-May 2021. In all groups, mask use increased again in July 2021, which aligns with public health concerns around the Delta variant. Independent predictors of higher mask use include vaccination, aged 65 and older, female sex, racial or ethnic minority group, and healthcare worker occupation, whereas a history of self-reported prior COVID-19 illness was associated with lower use.
Supplemental surveys were distributed to participants in the winter of 2020 to collect self-reported information on protective behaviors while gathering with friends and family outside their immediate household and if they engaged in protective behaviors including hand washing, social distancing, mask wearing, gathering outdoors, and COVID-19 testing. Significant findings include self-report of gathering with non-household members at Thanksgiving (47%) and during the winter holidays (69%). Only 30-40% of participants wore masks and less than 1/5th were tested prior to gathering.
The study team also distributed a supplemental survey to identify vaccine hesitancy. Results showed that 76% of those who responded intended to get the vaccine, but the data also identified hesitancy in African Americans, suburbanites, women, and those with prior infection. Participants most frequently cited concern over safety and lack of testing. Vaccine updates from participants were monitored through May of 2021. Subsequent vaccine uptake was 99% in non-hesitant participants and more than 50% in those who were initially resistant.
The MedStar Health study site is led by William S. Weintraub, MD, Director of Population Health Research, MedStar Health Research Institute; and Kristen E. Miller, DrPH, Scientific Director, National Center for Human Factors in Healthcare, MedStar Health Research Institute.
