DENVER -- With the quarantine of more than 90 cadets at the Air Force Academy and area camps closing because of H1N1, there appears to have been a resurgence in the virus.

This month's Nature magazine features an article about the ability of H1N1 to cause serious illness.

"When the scientists did the study on the virulence, or severity of the H1N1 virus, they discovered that unlike a normal flu virus, this virus has a particular ability to infect the cells deep in the lungs, causing pneumonia," said Dr. Dianne McCallister, the chief medical officer at Porter Adventist Hospital.

Normal seasonal flu viruses do not exhibit this.

Researchers also looked at patients who were alive during the 1918 flu pandemic. They found the patients had antibodies to H1N1, raising concern this flu season will be more serious than past seasons.

"A very important difference between now and 1918 is that we now have drugs that can help reduce the severity of an infection - and that help prevent spread of the flu - this did not exist in 1918" cautioned McCallister.

Porter Hospital is advising people to prepare for this year's season just like any flu season. That means being diligent about washing hands, covering coughs and sneezes, keeping hands away from the face and staying home when sick.

The hospital also reminders patients to talk with their doctors about the vaccine.

"You may have heard that some of the H1N1 is resistant to Tamiflu - but that is just a few cases out of tens of thousands of cases. Most of the H1N1 still responds to Tamiflu," said Mccallister.

Every Monday Dr. Dianne McCallister appears on the morning show. You can chat with her online following the program at blog.porterhospital.org.