Vaccine providers in Illinois can immediately resume giving Johnson & Johnson’s one-dose immunization after federal officials determined the shot’s benefits outweigh the risks of rare but severe blood clots, state health officials said late Friday.

The federal Centers for Disease Control and Prevention and the Food and Drug Administration lifted an 11-day pause on the use of the vaccine after an advisory panel said it was safe to do so in combination with a new warning about the risk of blood clots, particularly among women under 50.

Federal health officials said they were aware of 15 cases of the unusual clots since the government authorized use of the vaccine and nearly 8 million shots were given. All were women, most of them under 50. Three died, and seven remained hospitalized.

Illinois and the city of Chicago followed federal guidance in pausing administration of the Johnson & Johnson vaccine April 13 after reports about six women who’d experienced blood clots about two weeks after vaccination.

“The pause was proof that the extensive safety monitoring system is working and was able to detect a very small number of adverse events,” the Illinois Department of Public Health said in a statement Friday.

New shipments of the J&J vaccine are expected to resume next week, but only about 290,000 of the 760,000 doses that were sent to Illinois before the pause have been used, according to the state agency.

The Cook County Department of Public Health said in a statement that “it was able to retain virtually every (Johnson & Johnson ) dose we had on hand and look forward to vaccinating our residents as early as next week.”

Halting the J&J vaccine was a setback to city and state vaccination efforts because it represented an easier alternative to the two-dose regimen from Pfizer and Moderna. Officials had portrayed the one-shot version as an important step toward speeding up vaccination efforts, particularly in hard-to-reach communities, but they downplayed its significance when the pause was announced.

At the time distribution was paused, only about 4% of the vaccines administered statewide had been J&J’s version, covering a little more than 2% of the state’s population, according to the state health department.

Still, government-run mass vaccinations sites, as well as retail pharmacies, hospitals and clinics, had to cancel appointments and pivot to offering more slots for the two-dose vaccines.

Earlier in the week, Cook County Department of Public Health co-lead Dr. Rachel Rubin said the county was awaiting word from the federal government to resume using the one-dose vaccine.

“Many people are asking for the Johnson & Johnson one-dose vaccine,” Rubin said Tuesday. “We will continue to offer it once it is approved for use again.”

The return of the Johnson & Johnson vaccine would come at a critical time in Illinois’ fight against the pandemic.

An additional 136,525 coronavirus vaccinations were administered in Illinois on Thursday as the state reported another slight downtick in the seven-day coronavirus positivity rate.

The latest batch of shots brought the total number of doses administered in the state to 8,610,478, public health officials reported. As of Friday, 51.58% of residents 16 and older have received at least one dose of the coronavirus vaccine.

The number of residents who have been fully vaccinated — receiving both of the required two shots, or Johnson & Johnson’s one shot — reached 3,648,936, or 28.64% of the total population.

Over the last seven days, the state reached an average of 118,741 vaccines administered daily.

But that’s down from a peak of 132,979 shots per day on April 12 — the same day everyone 16 and older outside Chicago became eligible to be vaccinated.

After seeing a third surge of the pandemic take hold this spring, the state is starting to see some progress in slowing the spread of the virus.

The statewide case positivity rate — the percentage of new cases as a share of total tests — reached a seven-day average of 3.6% on Thursday, down from 3.8% the day before and 4.2% one week earlier.

Officials reported 3,369 new confirmed and probable cases of COVID-19 on Friday, resulting from 104,795 tests. Over the past week, the state has averaged 2,816 cases per day, down from an average of 3,312 the prior week.

Hospitalizations continue to be a concern, however, with the seven-day average of people hospitalized with COVID-19 rising every day since March 17, the day before Gov. J.B. Pritzker unveiled his revamped reopening plan.

The latest seven-day hospitalization average is 2,165, the highest since an average of 2,211 was recorded Feb. 9.

Officials also reported 22 additional fatalities, contributing to a statewide death toll of 21,777. The total number of known infections in Illinois since the start of the pandemic reached 1,316,091.

Chicago Tribune’s Alice Yin and The Associated Press contributed.

dpetrella@chicagotribune.com