At least three Chicago area  hospitals remain on bypass, as ambulances are diverted to other hospitals where doctors are seeing an onslaught of patients being tested for influenza.

There have been so many patients at Rush University Medical Center, 1620 West Harrison Street, that doctors ran out of testing kits for a short time.

The University of Chicago, Trinity, and Swedish Covenant hospitals are all on bypass status because they are at capacity.

Doctors suspect this year’s strong flu strain has been seen before but it has likely mutated, and even those who got vaccinated could contract a mild case of the flu.

“Our bodies have not seen this strain yet, so we are mounting significant immunity to it just now,”  Dr. Yanina Purim Shem-Tov of Rush University Medical Center told WGN.  “We haven’t been exposed to this strain in a long time.”

Forty-one states, including Illinois and Indiana, have now reported widespread flu cases.   As of last week, health officials reported seven flu deaths in Indiana and five in Illinois.  Nationwide 18 children have died from the flu.

Doctors are stressing the importance of hand washing and staying at home if you are sick.  And it is not too late to get a flu shot since the season could go on for another couple of months.