University of South Florida

USF Health research shows vaccination rate must double to slow transmission of COVID-19
COVID-19 vaccine vials


TAMPA, Fla. (July 23, 2021)– New data provided by University of South Florida College of Public Health epidemiologist Edwin Michael, PhD, and colleague Ken Newcomb shows that there’s been a 70 percent drop in the rate of people getting vaccinated in Hillsborough County since April. There are currently 2,000 people receiving the vaccine each day. Unless that figure doubles, Michael says that control of the resurgence of the pandemic over this fall will not be achieved.


“The upsurge in cases and hospitalizations are due to fewer vaccinations, relaxation of social distancing measures, greater population mobility, plus the spread of more contagious variants, which are also slightly better in evading immunity and likely cause more symptomatic disease compared to the original variant.” Michael said. “These predictions warn that until vaccination rates are ramped up to achieve herd immunity over this fall, people will still need to follow social distancing measures, such as wearing face coverings at the very least, to protect themselves and to reduce infection spread.”


Michael’s SEIRcast COVID-19 Forecast and Planning Portal shows that the slowing of vaccination since April combined with a steady reduction in the practice of social mitigation measures and the spread of the highly contagious alpha and delta variants will lead to a new spike in cases by mid-September, with 2,800 cases reported in Hillsborough County each day. The size of the spike with be three times greater than that observed during the second wave observed last winter.

Edwin Michael, PhD, is a USF Health College of Public Health epidemiologist who studies the spread and control of global infectious diseases.


He expects this September spike to be the final wave of the pandemic, which will primarily occur within the unvaccinated population. However, this will prompt a new surge in hospitalizations, potentially exceeding hospital bed capacity.


While there have been some infections reported by vaccinated individuals, their cases have been relatively mild, with very few requiring hospitalization. Nearly 48 percent of the population in Florida has been fully vaccinated. Michael says we will not reach herd immunity until that figure increases to 85 percent. This is higher than previous projections due to the prevalence of dominant variants. He says the next two months are crucial in trying to put an end to the pandemic.

Network-wide options by YD - Freelance Wordpress Developer