The nation’s top public health agency declared a flu epidemic Tuesday, warning residents to exercise caution in public spaces and use good, basic sanitary habits. And even though it may miss the dominant flu strain this year, experts continued to urge people to get the flu shot, saying that it certainly can’t hurt.
Infectious disease experts in the Sacramento region confirmed that influenza activity has been on an uptick here during the past two weeks.
But, as in past years, the flu has hit states east of the Rockies the hardest early on in the season, giving Californians advance notice of just how harsh an outcome to expect.
Already, 15 children have died of the flu in the upper Midwest and Southern states as of the week ending Dec. 21, the most recent reporting period tracked by the U.S. Centers for Disease Control and Prevention. A week earlier, the fatality count had been four children, CDC epidemiologists said.
This year’s prevalent strain, called Influenza A H3N2, is considered particularly hazardous to children and people older than 65 years, experts say.
Making matters worse is that, since last spring, the strain has been mutating into virulent versions of the H3N2 virus that are different than those this year’s vaccine was specifically designed to target.
But infectious disease experts say it’s still better to get inoculated because there may be some benefit to the vaccine due to possible overlap among the viral strains.
“The flu vaccine is not a total waste,” said Dr. Stuart Cohen, chief of infectious diseases at UC Davis Medical systems. “I’m still giving it to my patients.
“It’s only a modest change in the virus between what’s in the vaccine and what’s out there circulating,” Cohen said. “I wouldn’t totally give up on the vaccine.”
Cohen estimated, however, that about three-quarters of the respiratory flu virus that’s spreading nationwide has mutated, changing its genetic code.
That means that the virus the flu vaccine was formulated to attack will be unrecognizable to the finely tuned antibodies the vaccine produced in the human body.
Along with an altered genetic code, the mutations will have a different shape that’s foreign to the antibodies formed to act as soldiers on the front lines of battle against H3N2.
In essence, those soldiers will be blind to the hazards of the mutated version, and may likely open the gates to the body’s immune system, allowing the harmful interlopers to glide right by to sicken the host.
CDC head Tom Frieden had notified the public earlier in December that the flu season could shape up as a bad one because of the viral mutations.
By the time experts had discovered the extent of the mutated population of H3N2s, it was too late to formulate a new version of the flu vaccine for the 2014-2015 flu season.
But, there’s an exception: Drug companies are producing a new version of the flu vaccine that will be effective against the mutations in the globe’s Southern Hemisphere, where winter coincides with 2015’s summer months in North America.
As the mutant, rogue version of the virus continues its march toward the West Coast, the Sacramento region remains low to moderate in activity of the flu.
The CDC’s threshold for an epidemic is defined as 6.8 percent of all specimens – from patients with flu-like symptoms – testing positive for flu viruses.
Dr. Randy Bergen, the chief of infectious diseases for Kaiser Permanente in Northern California, said, by his tally, the positive specimen count has plateaued at about 10 percent of all samples tested.
Bergen said the acceleration in the number of positive cases slowed somewhat when school districts started their holiday season break. That would mean fewer kids gathered together in the closed classroom environment, and therefore, less opportunity for flu viruses to spread.
“It’s definitely spreading among families,” he said, judging by the volume of queries coming into the health system’s call centers.
“The numbers nationwide are worrisome,” Bergen said, “for the number of tragic cases of otherwise healthy young people falling ill.”
He said he’s been giving high-dose flu vaccines to patients in the other major group considered at-risk this flu season, people 65 and up. Currently, all available supplies of those high-concentrated vaccines have been used up, he said, and drug manufacturers are not expected to produce more this season.
Older people are asking if they should get a second flu shot to boost their immune systems to a level equal to that prompted by a high-dose vaccine, he said.
The answer is no; a second flu shot in any season would be ill-advised by any doctor, he said.
Cohen, meanwhile, stressed that people should take extra precautions by washing their hands frequently and avoid people who are sick and coughing, potentially spraying minuscule parts of the virus into the air.
At the same time, people should avoid what he called “high-touch surfaces” like doorknobs or handrails.
Cohen added: “If you’re playing cards with somebody who’s sick, don’t let them deal the cards.”
Officials said California has registered only one death so far, that of an older Los Angeles woman who had underlying medical conditions that likely weakened her immune system.
For those who do get the flu, a good treatment option is one of the anti-viral drugs approved by the Food and Drug Administration, from the well-known Tamiflu to new anti-virals for adults such as Rapivab, which is given intravenously.
Call The Bee’s Cynthia H. Craft, (916) 321-1270.