The CSSE confirmed there were 677,347 COVID-19 cases in Cook County by Nov. 30.
There were 11,496 fatalities, equalling 1.7 percent of Cook County's COVID-19 patients.
More than 50 percent of US citizens are considered fully vaccinated against COVID-19, nearing the target for "herd immunity." Herd immunity happens when enough of the population has become immune to the virus from previous infection that it effectively protects those who are not immune.
"The number of people who are immune to the coronavirus is increasing every day," professors David Dowdy and Gypsyamber D'Souza said in an interview.
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