A health care worker is vaccinated at a city-run vaccine site.

CHICAGO — Federal officials shared three studies they say bolster their decision to start a coronavirus vaccine booster program.

The studies show coronavirus vaccines are still highly effective at preventing severe illness and death, but their effectiveness has weakened over the past several months, according to The New York Times.

Federal officials said the studies suggest booster shots are needed to protect people from COVID-19, backing up the Biden’s administration to roll out a booster campaign Sept. 20.

The booster campaign has proven controversial: Some experts have said boosters should be saved for people most at risk — like people whose immune systems are severely compromised — while the bulk of doses go to countries where far fewer people are vaccinated.

The World Health Organization has said booster programs in wealthier countries could keep doses out of the hands of lower-income countries, which are struggling to get doses to vaccinate people. That could, in turn, fuel the emerge of more dangerous variants of COVID-19, experts have said.

The announcement comes as the highly contagious Delta variant has fueled another wave of coronavirus cases. Chicago has seen its cases surge, and hospitalizations and COVID-19 deaths have begun to rise.

The latest wave of coronavirus has had the deepest impact on unvaccinated people. About 97 percent of Chicagoans who have been hospitalized with or died from COVID-19 since January were not vaccinated, local officials have said.

As cases have risen, officials have brought the city’s indoor mask mandate. It went into effect Friday.


• In Illinois, about 6.6 million people of all ages — or 52.32 percent of the state’s 12.7 million people — have gotten all their COVID-19 vaccine shots, according to state data.

• Across the state, 33,564 vaccine doses are being administered per day, based on a seven-day rolling average.

• Illinois and Chicago have administered at least 13,745,822 vaccine doses of the 15,796,935 provided to them.

• City data shows more than 1.46 million Chicagoans — or 54.4 percent of all residents — have gotten fully vaccinated. About 59.8 percent of all Chicagoans have gotten at least one shot.

COVID-19 vaccinations are free and do not require insurance. Anyone can call the city’s coronavirus hotline at 312-746-4835 to get more information on how and where to get vaccinated in their community.

The numbers:

• Eighteen Illinoisans were reported dead from COVID-19 since Thursday.

• At least 23,717 people have died from COVID-19 in Illinois, and another 2,506 deaths are probably related to the virus, according to the state.

• The state reported 4,904 cases since Thursday. That brings the total number of confirmed cases in Illinois up to 1,482,369.

• Since Thursday, 90,749 tests were reported statewide. In all, 28,072,697 tests have been reported in Illinois.

• Illinois’ seven-day positivity rate was at 5.3 percent. The figure represents the percentage of people testing positive among recent tests. It was at 5.2 percent Thursday.

• Illinois’ seven-day test positivity rate, which measures the percentage of tests that were positive, was at 6.1 percent. It was at 6.2 percent Thursday.

• As of Thursday night, 468 people with COVID-19 were in the ICU and 234 people with COVID-19 were using ventilators in Illinois.

• In Chicago, six deaths were reported since Thursday. There have been at least 5,580 deaths from COVID-19 in Chicago. The city is seeing an average of more than three deaths per day, 29 percent increase from the week prior.

• Chicago has had 656 confirmed cases reported since Thursday. It’s had a total of 298,166 confirmed cases. An average of 462 confirmed cases are being reported per day, a 25 percent increase from the week prior.

• At the same time, testing has increased 1 percent since a week ago.

• Chicago’s positivity rate was at 4.7 percent, up from 3.8 percent the week prior.

Block Club Chicago’s coronavirus coverage is free for all readers. Block Club is an independent, 501(c)(3), journalist-run newsroom.

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