After a slow approach, the flu season is suddenly upon the Sacramento region, with two influenza deaths recorded in late December, officials said.
Physicians say they are beginning to see signs that it's only a matter of time before the widespread nationwide outbreak takes hold in Sacramento.
Dr. David Herbert, chief of infectious diseases at Kaiser Permanente, said he is noticing "an uptick in vaccinations and in people coming in with flu-like symptoms to clinics, the hospital and the intensive care unit."
"To the extent that the rest of the country is experiencing the flu, we will expect to see something similar in Sacramento," Herbert said Wednesday.
Because Kaiser has 40 to 50 percent of the market of insured consumers in Northern California, it is instrumental in helping the California Department of Public Health track the severity of the seasonal flu.
Herbert said these first two weeks of January have shown a notable increase in the number of people coming in with flu-like illnesses.
Even before the new year, the last two weeks of December showed a bump in influenza activity.
Kate McAuley is the immunization project coordinator for Sacramento County.
"We really didn't see too much activity in the fall, with the weather so nice," McAuley said. "But the influenza seems to have had a rapid uptick here in December."
Of the two residents who died of the flu, one was a young man and the other was an elderly patient. Their identities were being withheld.
The wintertime lurch is unlikely to flatten out anytime soon, McAuley agreed. "We'll reach a peak of activity in January and February," she said.
Overall, the California Department of Public Health, which crunches flu data from numerous sources, upgraded the state's influenza activity level to "regional," records show, meaning the flu has spread geographically.
On the scale of the Centers for Disease Control and Prevention, "regional" is one level below "widespread," the most severe CDC category for influenza outbreaks.
McAuley advised anyone who feels flu-like with fever, headache, body aches, sore throat and cough to stay home.
Others should wash their hands frequently, especially when touching surfaces where the virus may have been transmitted and where it may live on for a few hours.
It's not too late, however, for people to get vaccinated to protect themselves and their loved ones, said Herbert. Flu vaccines are still available at clinics, pharmacies and grocery stores, as well as health care providers' facilities.
"Even if it's as late as June, we encourage people to go ahead and get a flu vaccine," said McAuley.
The CDC said the vaccines are designed to protect against three particular flu viruses that experts have predicted will be most common in the current season.
Flu shots are good for one year only. They are made with inactivated or extinguished viruses and are recommended for anyone over 6 months old, with the exception of people with chronic health conditions.
Even after receiving a flu shot, a patient is still vulnerable to influenza for up to 2.5 weeks, while the body builds up a healthy resistance to the viruses.
Mild reactions such as soreness, headaches and fever are common side effects of the flu vaccine in some people.