The flu season has hit Hawaii suddenly with hospitals reporting a surge in patients.

"Hospitals are being constrained by a large influx of individuals with some type of viral illness we believe is influenza," said Toby Clairmont, director of emergency services for the hospital group Healthcare Association of Hawaii. "It started becoming significant over the weekend. The ones that do get it get really sick."

Hospitals have been stressed by the effects of the virus, with their emergency rooms getting backed up and more patients being admitted, Clairmont said.

"On Monday night seven of the ERs in Hono­lulu were closed to ambulances," he said. "The other effect we see is from neighbor island hospitals when they’re trying to transfer people to Hono­lulu, that gets delayed. It hit us kind of hard, more than we expected."

Kalihi resident Nicole Niau, 27, had fever, body aches and cold symptoms including a runny nose and sore throat so severe last week that she could barely get out of bed. Her boyfriend, Rob McGarry, 30, also fell ill for at least two weeks, she said.

"You can’t really move," Niau said. "Doing anything causes you to be really tired. I felt really weak and my body was super sore. I needed help walking."

Both Niau and McGarry were advised to stay home from their jobs at a Wai­kiki restaurant for five days.

"Everybody at work was sick, and we were short-staffed and everybody brought it to work. That’s how I got it," Niau added.

State epidemiologist Sarah Park said she expected an uptick in influenza following record levels on the mainland.

"We’re not safe from any disease that’s out there. It’s going to eventually make its way here because we have travelers," Park said. "What we’re hearing about should not be unexpected."

Though the state Health Department’s influenza data is about two weeks behind, Park said preliminary data indicate that flu cases are up. The islands typically see influenza cases spike around January and February, lagging the mainland by about a month, she said.

"We’re definitely hearing urgent-care clinics seeing more activity," she said. "Are we going to see the level of activity the mainland is seeing? It’s hard to say. I can’t predict that; no one can."

Influenza has reached epidemic levels on the mainland this year, with more deaths attributed to the virus than a year ago. The flu season here could be prolonged into April, Park said.

Don Olden, chief executive officer of Wahiawa General Hospital, said the rural facility has seen about a 10 percent bump in patients over the last few weeks to more than 60 from an average of 55.

"Yesterday I know we had patients trying to get admitted into hospitals, and hospitals were all full," he said. "Every year all the ERs at about January, plus or minus a month, start seeing upticks in ER visits ’cause it’s flu season. The number of problem cases on the mainland has been high. We’re probably a little more concerned this year than in prior years. There can be a stronger type of flu that’ll impact more people."

The concern is that one of the major flu strains is not covered by this year’s vaccination. The flu shot is only 23 percent effective, according to a government study released Thursday. This year’s formula didn’t include the strain of H3N2 virus that ended up causing about two-thirds of the illnesses on the mainland this winter. The strain tends to cause more hospitalizations and deaths, particularly in seniors.

"We are seeing increased cases of the flu both in clinics and hospitals," said Kaiser Permanente Hawaii spokes­woman Laura Lott.

Kristen Bonilla, spokes­woman for Straub Clinic & Hospital and Pali Momi Medical Center, said the facilities also have seen an increase in positive influenza cases as well as a rise in the overall patient census.

In the past few weeks primary care physician Cora­lie Texeira confirmed seven cases of influenza A in her practice at the Queen’s Medical Center-West.

"About three of those seven cases did have the flu shot. Two of those cases may have caught it on the mainland coming back home," she said. "We’re seeing a lot. It’s hit Hawaii. I’m concerned mostly for the elderly. We do have a lot of elderly in Hawaii, and we do have a lot of respiratory illnesses because of the vog. That’s not going to help if they now catch influenza."

Vulnerable populations including patients with pre-existing medical conditions like diabetes, heart disease, cancer, asthma or any kind of lung disorder are at risk for complications that require hospitalization or could lead to death. Other high-risk groups include babies, children under 5 years old and the elderly population whose immune systems are not as robust as younger people, Park added.

"These are the people we need to protect," she said. "I’m concerned it could be a bad flu season, but at the same time I’m hoping to push prevention issues. If people take action right now, get vaccinated and stay at home if they’re sick, we could actually not see any of that. If we protect everyone else around us, we have the potential to not see the level of activity they’ve been seeing on the mainland. It’s all hinging upon the entire community doing this together."