Cook County officials warned Thursday that cases of the delta coronavirus variant are surging, asking residents who have not yet been vaccinated to get their shots in an effort to prevent spread.
"The variant continues to surge and while research suggests that vaccinated individuals are generally protected, we know that there are still large segments of our population that are unvaccinated and high risk this infectious variant," Cook County Board President Toni Preckwinkle said during a coronavirus update alongside health officials.
It's a trend being reported across the state in recent weeks, particularly in parts of the state that have lower vaccination rates.
"There is a very clear connection between where those case rates are growing the fastest and how well that area is vaccinated," Illinois Department of Public Health Director Dr. Ngozi Ezike. "I.e. the more highly vaccinated areas are having lower case rates."
Preckwinkle noted that just under 60% of Cook County residents have received at least one dose of the vaccine.
"However 70-80% is needed to reach herd immunity," she added. "So we're a ways from that."
Health officials have said the delta variant has a higher transmissibility that impacts more people at a time than previous variants. Within weeks, Ezike said Illinois has seen COVID cases double statewide.
Studies have shown that the delta variant spreads approximately 225% faster than the original strain of the virus. Studies have also shown that once a person catches the delta variant, they likely become infectious sooner, and that the virus grows more rapidly inside a person’s respiratory tract.
Areas of western and southern Illinois are seeing increases in positivity rates and coronavirus-related hospitalizations in recent weeks, continuing a recent trend that’s seeing COVID metrics slowly on the rise in many areas.
In Region 4, located near St. Louis in southwestern Illinois, the positivity rate has more than quadrupled in the last month, rising from 1.8% on June 11 to 7.5% on July 10, according to metrics from IDPH.
A recent trend of increases in COVID hospitalizations has eased in recent days, with the number of hospitalizations remaining steady or decreasing on four of the previous five days, and ICU bed availability has also steadied after a decline earlier this month, with 31% of the region’s ICU beds currently available.
Region 3, located in western Illinois and comprised of an area that includes Springfield, is also seeing elevated positivity rates, with that number now at 5%. Hospitalizations have increased on eight of the last 10 days in the region, with ICU bed availability at 29%.
Region 5, located in southern Illinois, is also dealing with increases in COVID cases, with a 5.4% positivity rate over the last week. ICU bed availability has decreased to 22%, and hospitalizations due to COVID have increased on each of the last 10 days.
Areas of northeastern Illinois have seen small increases in positivity rates, but none of the five health care regions that comprise the NBC 5 viewing area have a positivity rate of higher than 1.5%. Hospitalizations are mostly decreasing in those regions, although Region 8, comprised of Kane and DuPage counties, and Region 11, the city of Chicago, have seen hospitalizations due to COVID increase on six of the preceding 10 days.
Those dramatic increases come as Missouri sees some of the highest COVID case rates in the nation. According to the state’s latest numbers, published by the St. Louis Post-Dispatch, less than 40% of Missouri residents have been fully vaccinated, and in some rural counties, that number is less than 20%.
But according to both Ezike and Cook County Department of Public Health Co-lead Dr. Kiran Joshi, vaccines are so far providing protection in the state.
"We have seen some [breakthrough cases]. Are they increasing? No," Joshi said, referring to cases in which fully vaccinated people contract COVID-19. "We know the vaccines are incredibly effective."
Illinois' top doctor said Tuesday that breakthrough cases of COVID-19 in fully vaccinated residents are a "unicorn."
"These vaccines are truly effective," Ezike said. "You know, everyone has heard of a case or two of someone who had a breakthrough infection or breakthrough hospitalization, but it is, that is so far the unicorn, that you need to focus on the people who are not vaccinated, they're the ones filling up the hospital as COVID patients."
Just over 2% of COVID-19 deaths in Illinois so far this year have been among fully vaccinated residents, known as "breakthrough" cases, according to state health officials.
A total of 151 people in Illinois have died due to COVID-19 or complications after being fully vaccinated, according to data updated Wednesday by the Illinois Department of Public Health. That figure equates to 2.2% of COVID-19 deaths in the state since Jan. 1, officials said.
At least 563 fully vaccinated people have been hospitalized in Illinois, IDPH said. The state only reports breakthrough infections among those who have been hospitalized or died, IDPH said.
A person is considered “fully vaccinated” two weeks after receiving the second dose of either the Pfizer or Moderna COVID vaccine, or two weeks after receiving the single-dose Johnson & Johnson vaccine.
The state does not publicize the number of residents who tested positive after being fully vaccinated but did not die or require hospitalization in order to "help maximize the quality of the data collected on cases of greatest clinical and public health importance," IDPH's website reads.