VIGO COUNTY, Ind. (WTHI) -- Herd immunity is something we see with other diseases like measles and polio. But, health officials say they just don't know if we will see it with COVID-19.
According to the World Health Organization, herd immunity is a concept used for vaccination in which a population can be protected from a certain virus if a threshold of vaccinations is reached.

Basically, if you get enough people immune there is no one to spread to people who are not immune.
With polio, if 80% of people are vaccinated that will protect the other 20%. With measles, it's 95%. But, what about COVID-19?
"We're not really sure what COVID-19 is going to be because it's so new," Roni Elder, with the Vigo County Health Department said.
She said the one thing health officials know is that they do not want to wait until everyone gets the disease to find out what that number is.
"The only hope we have with herd immunity for COVID-19 is the vaccine," Elder said. "We do not want COVID-19 to just get herd immunity by people getting it because that will cause a lot of unnecessary health conditions, a lot of deaths and we don't know how many people actually have to be infected."
But, a vaccine isn't the foolproof answer either.
"You don't know how long the immunity is going to last from the vaccine and people have to get vaccinated. Some, may not because of health conditions or personal reasons," she said.
But right now, it's what health professionals and scientists said is the best answer.
"We'll see what happens as time goes on and hopefully that will be our answer because we gotta get the numbers down," Elder said.
Hospitals in Terre Haute said they could get a vaccine in just days. But, it will go to health care workers first. Officials said the public may not see a vaccine for a few months.