had been spared from the worst of it. And tonight just one image that helps paint the picture of so much misery. This is a google map of where rching online to learn anything they can about the flu.... See More
had been spared from the worst of it. And tonight just one image that helps paint the picture of so much misery. This is a google map of where rching online to learn anything they can about the flu. The searches began in the southeast where it first hit hard stretching across the country now westward and to california tonight, which is now bracing for its arrival. That's where mobile units are being put in place preparing for what this week will begin just as we get an exclusive look inside a hospital in boston on the other side of the country where children are fighting this flu, so we begin with abc's john schriffen. Reporter: Tonight, these young faces are among the most vulnerable. I don't even want to know what the flu will do to him. Reporter: Our team at "nightline" with rare inside access at boston children's hospital where the staff has kicked into overdrive wearing masks to try to treat this seemingly endless little of line patients. Hopefully the doctors here can make me better. Reporter: This year, even the healthiest adults are catching the flu. We asked our viewers to tell us how they're getting through it. Donya from washington, d.C. Decided not to get the flu shot and got sick for five days. I'm nursing myself at home drinking gatorade, keaching hydrated, and I was out for an entire week. Reporter: Lisa adam also didn't get the vaccine. Now she's on day five with the flu. Should be getting worse not better. Spent six hours in t emergency room with my dad in burbank on friday afternoon. There were hundreds of people in and out of that emergency room with the same thing. Reporter: Frankie from new york says he got the flu shot but didn't get sick even though his neighbors and aunt have it. It felt like I was getting a bad beating but I wound up with a bad headache, but that only lasted like two or three days. Reporter: Out west they're bracing for a spike in the flu. In los angeles, mobile clinics like these will be stocked with flu vaccine sent out into neighborhoods. In portland, clinics were packed after city pharmacies and doctors ran out of the vaccine. And if someone in your own family is coming down with flu symptoms, doctors advise avoid waiting here in the emergency room. Instead, call your own doctor first.
This transcript has been automatically generated and may not be 100% accurate.