Widely circulating variants and vaccine hesitancy is pushing herd immunity father out of reach then many experts expected.
For months, herd immunity seemed to be the endgame of the COVID-19 virus and the point when enough Americans would be protected against the virus to stop the spread.
70 percent seemed to be the key number to get back to normalcy, but because of the continued spread health experts are now pushing that number up.
"The early thinking was that the COVID-19 pandemic might start to fade once a chunk of the population, initially thought in the 60 to 70 percent range was vaccinated. But that percentage was never a magic threshold," said Dr. Lydia Watson, MidMichigan health chief medical officer.
The previous aim of a 70 percent vaccination rate is now closer to 80 to 90 percent because of the Delta variant.
"Because every virus is different and because now, we're starting to see some of those newer variants, we're concerned that this likely is moving the bar for herd immunity to higher levels," Watson said.
Watson said her hospital appears to be coming down from a peak in the latest COVID-19 surge. They are still learning about the virus every day.
"The COVID-19 virus is a new virus, so we really don't know as much about that virus as we do other viruses," Watson said.
Though previous infections do provide some immunity, we can't rely on that forever. She hopes the latest school outbreaks will propel more families to get the shot.
"It's not clear how long you're protected from getting sick again after you recovered from it once, and the second thing is that we don't want everybody to get covid so that we have herd immunity because that's going to cause serious complications and more deaths," Watson said.
80 percent to 90 percent vaccinated isn't new for viruses.
"With measles, we need to have 90 to 95 percent of the population vaccinated to cause herd immunity against measles and when we had polio the threshold was 80," Watson said.
Watson said we won't really know what the threshold for COVID-19 vaccination rates are until we get there.