The flu is spreading fiercely across the United States, with more than 40 states reporting widespread activity in what one of the nation's leading health officials is calling an epidemic.
"If you look at the charts that the (Centers for Disease Control and Prevention) put out on their website, it clearly has gone above that threshold. So we are into what would classically be described as a flu epidemic," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, told CNN's Wolf Blitzer on Thursday.
"It's still on the uptick," Fauci added.
The season has started earlier, and cases are more severe than last year, health officials say.
The latest Centers for Disease Control and Prevention flu advisory report, which covers the week of December 23 to 29, suggests that 41 states have widespread influenza activity, which was an increase of 31 states from the previous week. The CDC will issue an update on the flu situation Friday.
There have so far been 2,257 hospitalizations associated with laboratory-confirmed flu virus, the CDC report said. Among children, there have been 18 deaths reported during this season. Various state agencies also are compiling statistics on flu-related deaths.
This is only about week five in a 12-week flu season, according to Fauci.
"Remember, once it peaks, you still have a considerable amount of time where there is a lot of flu activity, and right now it may have peaked in some places, but for the most part, it has not yet peaked," he said.
A public health emergency in Boston
In Massachusetts, one of the 29 states that the CDC has identified as having high activity of influenza-like illness, Boston Mayor Thomas Menino declared a public health emergency in the city Wednesday because of the flu.
Since October 1, there have been 700 confirmed influenza cases among Boston residents, according to Menino's office; that's 10 times more than were seen in all of last year's flu season.
There have been 18 flu-related deaths this season in Massachusetts, CNN affiliate WCVB reported. Hospitalization rates are higher than the last two years, Kevin Cranston of the state's Bureau of Infectious Diseases told WCVB. Most deaths have been in older patients, he said.
Menino is collaborating with the Boston Public Health Commission and community health centers to offer free vaccination clinics this weekend. The mayor urged residents to stay home from work or school if they are sick, and to get their flu shots.
"This is the worst flu season we've seen since 2009, and people should take the threat of flu seriously," Menino said in a statement. More than 4% of emergency department visits at Boston hospitals are from flu cases, up from 1% during non-flu season.
Massachusetts General Hospital has already counted 532 cases of flu among patients, which is more than the Boston hospital saw in any of the previous three flu seasons, spokeswoman Kristen Stanton said Wednesday.
Signs posted throughout the hospital discourage anyone from visiting who has a cough or fever, she said, and anyone who does visit with those symptoms must wear a mask and perform hand hygiene. All staff must wear a mask when providing care for possible flu cases. Any staff member who has not been vaccinated must wear a mask while caring for any patient.
In Onondaga County, New York, health officials counted 2,347 flu-season cases through last Saturday. In 2011, during the same seasonal time period, they counted five flu cases.
Somerville, Massachusetts, a small city north of Boston, announced that the city's supply of flu vaccine for the season had run out. All 720 doses for the season that were being administered for free had been given out by Tuesday. Residents looking to get vaccinated should contact their primary care physician or local pharmacy, the website said.
That the city's vaccines have all been given out is somewhat surprising because normally there are about 100 doses left over at the end of a season, spokeswoman Jackie Rossetti said Thursday. She attributes this to an earlier start of the flu season and outreach efforts.
Somerville has asked the state's public health department if there are any more available vaccines for the city and is waiting to hear back, she said. Most local pharmacies have doses left, however, she said.