What are the chances that you have been exposed to COVID and have not fallen ill?

If you’ve been out and have been living your life since being fully vaccinated, you might be curious about whether you’ve been in contact with the coronavirus. Could you be one of the lucky ones who had an asymptomatic infection? Or, is there still a good chance that you haven’t encountered the virus yet?

The delta variant is all over, and it spreads much faster than previous variants. Many people infected with the delta are extremely contagious and have viral loads hundreds of times more than they would have with the original strain. So if you go places like restaurants or gyms with a group of strangers, it seems inevitable that you will be exposed at some point.

“It’s really so transmissible that I think there’s a good chance, depending on the community transmission rate in your area – whether you have a substantial or high transmission rate in your area depending on the CDC Definitions – that you may have been exposed, ”said Monique Gandhi, infectious disease specialist at the University of California at San Francisco.

Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, said it was crucial to differentiate between exposure and infection. Being exposed to or being in the presence of a virus does not necessarily mean that you will be infected or develop symptomatic illness (although some people, regardless of their vaccination status, certainly will).

Delta is so transmissible that if you’ve been in a very large area – and weren’t wearing a mask or social distancing – there’s a good chance you’ve been exposed, according to Gandhi. As case rates increase, the likelihood of coming into contact with the virus also increases.

There’s a good chance that many of us have experienced the virus before, but whether this exposure caused an infection depends on a few factors, Nuzzo said.

The first consideration is how close you were to the infected person who was shedding the virus. Second, the amount of virus that person was producing, because some people spread a lot more virus than others. Third, what the ventilation looked like – if you were exposed in a poorly ventilated room, there is a greater chance that the virus could have entered your cells. The host, or how your body handles the virus, also plays a role.

It depends. Many vaccinated people who have been exposed probably wouldn’t notice. They may have produced an immune response that was successful in fighting off the virus before it caused symptomatic illness. This is, after all, the purpose of vaccines.

You strength be able to detect the activation of your immune system. On close exposure, your memory B cells will start to shake and make antibodies, Gandhi explained, and your T cells will prepare to fight. Some people might experience this immune response, which could potentially resemble some of the side effects experienced after vaccination, as these are signs that your immune system has strengthened.

“In today’s environment, where we are all hyper-alert to symptoms, it’s possible for people to feel depressed or tired,” Gandhi said.

This one is complicated. Some research suggests that being exposed to infectious doses of SARS-CoV-2 enhances the immune response.

“There is known evidence that being exposed to an infection after receiving a dose of vaccine enhances the immune response. It allows your memory B cells to make antibodies, it allows your T cells to replicate, ”Gandhi said. (Those new antibodies produced by B cells, by the way, will target the new variant it sees.)

We definitely need more data on how exposures affect our immune memory. UK scientists are leading challenge trials, in which they expose healthy young adults to the coronavirus to better understand the doses that cause infection and how different people’s immune systems respond to exposure to the virus.

However, this does not means you want to get infected or get sick. There really is no great way to predict if you will get sick, how sick you will get, or whether you will develop long term symptoms if you do get sick.

This is especially true if you are not vaccinated without natural immunity against a previous infection. “The good thing about being vaccinated is that you are much less likely to get the disease, but [exposure] will boost your immune response, ”Gandhi said.

Remember: injections prevent disease, not infection.

“If you are well enough surrounded by the virus, there is a good chance that you will be infected,” Nuzzo said. The hope, she added, is that the vaccines will keep people from getting seriously ill. And in some cases, they will prevent people from having any disease.

The growing consensus among infectious disease specialists is that we are all going to encounter COVID at some point. Delta, as transmissible as it is, has been a game-changer – COVID is becoming rampant.

“I don’t think we’re going to eliminate him,” Gandhi said. “That, to me, means we’re all likely to be exposed at some point.”

And if we’re going to be exposed to COVID, it’s best to do so with some immunity. Get these vaccines.

Experts are still learning about COVID-19. The information in this story is what was known or available at the time of publication, but directions may change as scientists find out more about the virus. Please consult the Centers for Disease Control and Prevention for the most recent recommendations.