Delta variant of coronavirus arrives in Illinois with 64 cases diagnosed

Illinois Department of Public Health officials reported Tuesday that 64 cases of the “more transmissible” COVID-19 Delta variant have been diagnosed in the state.

While the cases make up less than 1% of the 9,423 variant cases diagnosed in Illinois, the U.S. Centers for Disease Control and Prevention on Tuesday declared it a “variant of concern.” The Delta strain joins four other variants with that classification.

It has been found in 14 Illinois counties, including Cook, DuPage, Kane and Lake counties, IDPH officials said Tuesday.

“From what we know, it's more transmissible than the other variants, 60% more transmissible than the Alpha (United Kingdom) variant, which is the predominant strain here in Illinois,” said Dr. Gregory Huhn, infectious disease physician and COVID-19 vaccine lead for Cook County Health. “But we are tracking it, it is emerging and we can expect that the rate of reporting and identification may double every two weeks.”

CDC researchers said the Delta variant accounted for 2.7% of new variant cases in the U.S. between May 9 and May 22, but 10% of new variant cases during the following two weeks.

“Unless we reach higher numbers of vaccination in our local communities, we would expect that this virus would gain more of a foothold in certain areas of the U.S.,” Huhn said.

First detected in India, the Delta variant is not only considered more transmissible, but monoclonal antibody treatments are not as effective in treating infection, the CDC reported. Researchers also say there's a slight decline in vaccine effectiveness with the Delta variant, but people who are fully vaccinated are not nearly as at-risk as those who are unvaccinated.

The two-dose vaccines from Pfizer and Moderna have shown effectiveness against the new strain, officials said. The efficacy of the single-dose Johnson & Johnson vaccine is still being studied. Researchers are hopeful because the AstraZeneca vaccine, which is similar to the Johnson & Johnson version, has proved effective in the United Kingdom, which is struggling to control a rise in cases caused by the Delta variant.

Reopening plans in the U.K. were pushed back for a month to fight the surge of new cases in mostly unvaccinated individuals.

“We should be concerned as Delta variant is more contagious and may be associated with a higher risk of hospitalization” than the original COVID-19 strain, said Will County Health Department epidemiologist Alpesh Patel. “Vaccination is the key to prevent widespread transmission. Studies show that two doses of the Pfizer shots are effective against the Delta strain, according to the National Institutes of Health. Two doses of the Pfizer vaccine were shown to be 88% effective against the Delta variant.”