Richard Taylor, clinical assistant professor in the School of Human Ecology, co-authored a study published in Frontiers in Public Health which estimated that 1.7 million vaccine doses are needed to reach herd immunity for COVID-19 in Travis County. A new model could help public health officials in Central Texas better manage what amounts to a much larger vaccination campaign than was carried out during the last pandemic.
According to one estimate from May 2020, the level of immunity needed to halt person-to-person transmission of COVID-19 is 67%. That is much higher than the level of immunity that was acquired through vaccination during the swine flu pandemic in 2009, according to the latest study. Then, 326,095 doses of the H1N1 vaccine were distributed to providers in Travis County, achieving a vaccine coverage rate of 31.8%.
The study estimates nearly 1.5 million doses for those with health insurance and almost 253,000 doses for those without health insurance must be administered to achieve a COVID-19 herd immunity rate of 67% using a 2-dose vaccine schedule.
"For those with health insurance, this represents nearly four times the quantity of vaccine distributed a decade ago," the study says. "This is an enormous increase in volume and represents a seismic shift in daily operations for private providers."
As of February 4, 171,600 doses have been allocated to Travis County and 109,655 doses have been administered, according to the Texas Department of State Health Services. In Travis county, over 82,000 people have received at least one dose, with more than 27,500 people fully vaccinated.
The study proposes a model that can be used by public health officials to estimate the vaccine quantity needed in a particular county and says partnering with a health insurance company that provides coverage within the jurisdiction can help identify vaccinator capacity.
"The goal of this recent research is to assist public health officials by quantifying the number of doses of vaccine to be administered in our community to reach herd immunity, which will enable our community to get back to normal," said Dr. John Litaker, PhD, the study's principal author.