TAMPA, Fla. — A new Moffitt Cancer Center study shows that the number of Hillsborough County residents who’ve been infected with COVID-19 is twofold the number of positive tests reported by the Florida Department of Health.
U.S. public health data shows the number of people who test positive for COVID, rates of hospitalization and deaths, but does not accurately reflect the actual extent of the pandemic. Why? These data do not take into account people who were symptomatic but did not undergo testing, and those with mild or no symptoms who were not tested. Early on in the pandemic, testing availability and eligibility requirements also changed.
In a new article published in the March issue of Emerging Infectious Diseases , a journal of the Centers for Disease Control and Prevention, Moffitt researchers set out to estimate the percentage of Hillsborough County residents who had COVID infection and better understand demographics and behavioral factors associated with infection.
COVID-19 antibodies can be detected seven days after symptoms begin and IgG antibodies are detectable within two weeks of infection. Antibody testing is an accurate marker of previous COVID infection regardless of whether symptoms were experienced.
As of June 1, 2021, Florida had the third highest number of confirmed COVID cases in the United States: 2,283,315 (10.6% of residents), resulting in 95,210 hospitalizations and 36,869 deaths. As of June 1, 2021, Hillsborough County had 142,013 positive tests out of approximately 1.47 million residents, or 9.7% of the population.
Moffitt researchers conducted a study of adults in Hillsborough County from October 2020-March 2021. Forty-thousand letters or postcards and 10,000 emails were sent to residents, resulting in a sample size of 867. Participants were scheduled for an in-person blood draw — excluding anyone experiencing symptoms — after completing a short questionnaire on demographics, COVID exposure history, underlying conditions, immunosuppression status and use of immunosuppressive medications.
Among 867 Hillsborough County residents who had not received a COVID vaccine, 19.5% tested antibody positive. This is twofold higher than the confirmed COVID infections reported by the Florida Department of Health for that period of time. Given molecular testing was not widely available early in the pandemic, and when it was available, not everyone experiencing symptoms sought testing, many who were infected were not counted in public health databases.
“A key finding of this study is that nearly 100% of persons who had confirmed or suspected infection were antibody-positive and remained antibody-positive even if the infection occurred more than six months before antibody testing,” said Dr. Anna Giuliano , the founding director of the Center for Immunization and Infection Research in Cancer at Moffitt. “A question that remains unanswered by our analysis and other studies is the duration of the antibody response among those who experienced infection with COVID-19.”
Other key findings include:
This study was supported by the National Cancer Institute (P30CA076292), private donations to the Moffitt Foundation, Merck Sharp & Dohme Corp and the National Institute of Allergy and Infectious Diseases (HHSN272201400008C).
About Moffitt Cancer Center
Moffitt is dedicated to one lifesaving mission: to contribute to the prevention and cure of cancer. The Tampa-based facility is one of only 52 National Cancer Institute-designated Comprehensive Cancer Centers , a distinction that recognizes Moffitt’s scientific excellence, multidisciplinary research, and robust training and education. Moffitt’s expert nursing staff is recognized by the American Nurses Credentialing Center with Magnet® status, its highest distinction. With more than 7,500 team members, Moffitt has an economic impact in the state of $2.4 billion. For more information, call 1-888-MOFFITT (1-888-663-3488), visit MOFFITT.org , and follow the momentum on Facebook , Twitter , Instagram and YouTube .
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Emerging Infectious Diseases
Observational study
People
SARS-CoV-2 Period Seroprevalence and Related Factors, Hillsborough County, Florida, USA, October 2020–March 2021
3-Mar-2022