Health officials explain why 'Super K' flu variant can lead to severe illness

SAN FRANCISCO (KGO) -- Hospitals in the Bay Area are reporting more "influenza-like illness," pointing to a mutation in the strain.

"There is this mutation seen in this H3N2 which is why it's gotten its own name under 'subclade K' as kind of the other medical terminology but I think the worry is that is there enough mutations in this virus which we see influenza do which is kind of drift into new versions of influenzas which when there is enough mutations we worry about the vaccine efficacy," said Luis Alberto Rubio, assistant professor of UCSF Infectious Diseases.

RELATED: How to protect kids amid new subclade K flu strain

Medical experts in the Bay Area are tracking what's happening nationwide to understand what's to come.

The CDC estimates: "There have been at least 7.5 million illnesses, and 3,100 deaths from flu this season so far. That is up from 4.6 million illnesses and 1,900 deaths just last week.

But is this strain worse than the one we saw last year?

"I think time will tell. I don't think we know right now. There has been a lot of alarm in different countries -- in Japan, UK, where there has been more cases early on in the year. So, I think that has gotten people alarmed," said Dr. Rubio.

In Santa Clara County, wastewater is giving this region a glimpse into the uptick of cases.

"We're seeing spread of influenza in our community. We're also seeing increases in emergency department visits due to influenza and hospitalizations," said Krishna Surasi, Assistant Public Health Officer at Santa Clara County Public Health Department.

Our data team confirmed the overall hospitalization rate in the Bay Area is a little over two people per 100,000 residents. The number is slightly higher in Santa Clara County.

RELATED: New flu variant 'super' K linked to spike in cases amid holiday gatherings

"The subclade K does belong to the H3N2 strain. And anytime we have an H3 predominant flu season, as opposed to, say, an H1N1 predominant season, we tend to see more severe impacts among, especially among, the elderly," said Dr. George Han, MPH, MD, Director of the Communicable Disease Branch at SFDPH.

Medical experts are recommending to still get vaccinated to prevent severe illness, especially those over 60 years old or young children, and ask your doctor about an antiviral medication.

"When you take that medicine, it shortens the length of your illness, and it helps prevent you from needing to go to the hospital," said Dr. Han.

The biggest worry with this strain is more severe disease.

"If you're sick, stay home until your fever's gone for at least 24 hours. If you have to cough or sneeze, do that into the crook of your elbow, not on your hands," said Surasi.

Dr. Rubio said hospitals are reporting infections and some inflammation of heart tissue associated with this strain.

"Seeing the uptick in cases week by week is kind of tipping us off that there are probably going to be more cases to come in January and February," said Dr. Rubio.