"That's quite a significant difference", said Dr. Eric Arts, a professor in Western University's department of microbiology and immunology.
Mass vaccination sites may be gone in Milwaukee, but the city continues to work with partners at several vaccine clinics, including one at Helfaer Field where people who get their shot on-site also get two free Brewers tickets.
With earlier variants, each individual infection resulted in three to five new cases, he added. "We just don't have that many cases these days, it's still around.we're closing COVID wards in certain hospitals, like we're shutting down COVID wards, because they're just not necessary in many hospitals", he said.
Milwaukee's Commissioner of Health, Kirsten Johnson, reported two cases of the Delta variant were detected in Milwaukee County at the end of May.
Is the new variant more transmissible?The risk of hospitalisation is more or less double than then in Alpha variant, the study further asserted.
Dr. Gerald Evans, chair of infectious diseases at Queen's University, said there could be a variety of reasons for this.
Health leaders in Milwaukee County believe the Delta coronavirus variant is concerning to residents as the Centers for Disease Control announced there is growing evidence the variant is more contagious and causes more severe cases.
"They have no protection". Experts say it could potentially be evolution of the virus, but it may also have something to do with the age of those infected. Moreover, the scientific analysis now in Public Health England journal found no deaths among the vaccinated who were studied.
The study, published on Monday, analyzed the medical records of 14,000 people who had become infected with the Delta variant between April 12 and June 4.