While health officials have warned parents to watch for possible symptoms of enterovirus D68, a respiratory illness that has sickened 938 people in 46 states and killed at least 3, little has been said about the risk for older adults.

“Anyone with a compromised immune system is going to be at risk,” Dr. John Young, a longtime emergency room physician in Florida, New York and Arizona hospitals who now specializes in chronic and genetic diseases in Key Largo, Florida, told FoxNews.com.

Symptoms of the virus can include fever, runny nose, skin rash or muscle and body aches. However, the virus seems to have become more virulent, especially for those with any type of chronic disease, such as diabetes or chronic asthma, as side effects can be worse.

“The immune system is not as good, so these viruses most of us could handle can be very deadly in these patients,” Young said.

Side effects of enterovirus D68 can include paralysis, brain swelling and more serious pneumonia.

Young noted that when older adults aren’t feeling well, they aren’t tested as quickly as young children in order to diagnose their illness.

“They’ve got so many problems, another cold, [doctors] just put it off to that,” he said.

However, older adults with compromised immune systems who contract enterovirus D68 may see the virus take a turn for the worse very quickly.

“If you have a cold, it’ll be bad for 3-4 days and start to get better,” he said. “With my patients I tell them this: If this is going more than four days and you’re not getting better or are getting worse, you need to get in here yesterday.”

When sick patients come in for treatment, they’re given antibiotics to prevent bacterial infection on top of the virus— antibiotics do not treat the virus itself— and are treated for side effects.

It may take weeks to get the virus under control in patients with compromised immune systems, but for the average person it should take a week or less.

Young suggests his patients increase their vitamin D levels up to 70 ng/mL to boost their immune systems. A normal level is anything over 30 ng/mL. Because Vitamin D raises calcium levels, be sure to have your doctor monitor your calcium levels.

“With adults, and kids also, the better you make the immune system, the better they’re going to fight that type of infection,” he said. “Vitamin D is probably the cheapest and easiest and one of the best things you can do is to get your Vitamin D levels up and I see this over and over.”

While enterovirus D68 is out there and has had fatal effects, Young noted that the majority of patients will not suffer from the harmful side effects.