Reaching herd immunity against COVID in Illinois likely a 'longer process' than hoped
When COVID-19 vaccines began flying into the arms of health care workers in December, there was a mass exhale as hopes of quenching the deadly pandemic seemed achievable for the first time.
Come February, frustration built as thousands sought to be vaccinated amid a trickle of doses. Now that it's May, vaccinations are plentiful but demand in Illinois is down -- raising concerns that the state will never reach herd immunity, which would signal a return to normalcy.
On Monday, the Illinois Department of Public Health announced the state's seven-day average for vaccinations was 78,440 shots compared to 110,057 a month ago on April 3.
The goal of herd immunity is to effectively stamp out a disease and that happens when enough people in a community are protected because they've been vaccinated or were infected and recovered.
"We are still learning about the (COVID-19) disease so we don't know what proportion of the populations needs to be immune to stop its spread," IDPH spokeswoman Melaney Arnold said Monday. "Highly contagious diseases, like measles, needs a higher proportion of the population (estimated at 94%) to be immune and interrupt the transmission of measles.
"From the beginning of the pandemic to now, estimates on herd immunity have changed ranging anywhere from 60% to 90% for COVID-19. Currently, the vaccine has been found to be effective against variants of concern, but it's difficult to predict what will happen. What we need right now is for as many people as possible to get vaccinated to stop transmission of the virus. Without greater immunity, the virus will continue to circulate and our ability to return to normal ... will take longer," Arnold said.
In suburban Cook County, close to 1 million people, or about 45% of residents, have been vaccinated, public health department officials said.
"At this point, we believe it's too early to determine if herd immunity will be reached but continue to be optimistic as more people are being vaccinated every day," said Dr. Rachel Rubin, CCDPH senior public health medical officer.
Rubin agreed there are many unknowns about COVID-19 but said "scientists estimate up to 80 percent of the population will need to be immune to control the illness and reach herd immunity."
For those worried about never achieving herd immunity, the antidote is to convince someone to be vaccinated, experts say.
"The way to think about it is -- every single person who get vaccinated is one more place the virus can't go to," advised Dr. Michael Bauer, medical director at Northwestern Lake Forest Hospital.
"What we need to keep doing is vaccinating as many people as possible in the fastest way we can because we still have a very good window of opportunity before a potential late fall or early winter resurgence."
"If you add the number of people that are vaccinated and protected, and the large number of people that have been infected and presumably have a fair amount of natural immunity, it creates less and less avenues for the virus. With that certainly will come a decreased risk of mutations and resistant-type strains happening."
About 32% of Illinois' population is fully vaccinated.
As a point of reference, Bauer noted that Israel experienced a dive in COVID-19 infections after the country reached the 40% to 50% range of fully vaccinated residents. "They saw a precipitous drop in the numbers and once they hit 60% they really lowered," he said.
Regarding herd immunity, Edward Hospital's Dr. Jonathan Pinsky thinks the reality is, "it's probably going to be a lot longer process than what we would hope for. It's not like -- now vaccines are available and everyone is going to go out and get one immediately and we'll reach herd immunity."
That's because many people have cold feet about the vaccines, despite the fact 247 million shots have been administered in the U.S.
A significant number of the COVID-19 patients Pinsky is treating now at Edward Hospital are vaccine-hesitant, he said.
"What we're seeing are largely people in their 40s and 50s and early 60s who had not yet gotten vaccinated," said Pinsky, Edward's medical director of infection control and prevention. "Some of them were eligible to be vaccinated but decided to wait and many are regretting that decision."