LA Flu Cases Double, But Other Viruses Are Spreading Faster

In 2012, the Respiratory Syncytial Virus, which causes flu-like symptoms, reached its highest end-of-December level in LA in three years

Verified incidence rate of the flu more than doubled in Los Angeles during December but remains nowhere near as prevalent as other viruses that cause flu-like symptoms, according to the most recent statistics from the Los Angeles Public Health Department.

Growing faster is the Respiratory Syncytial Virus, RSV, often the culprit in respiratory tract infections in young children. RSV was at its highest end of December level in three years, as reported in the department's Jan. 4 Influenza Watch.

The health consequences of RSV are generally less severe than caused by influenza, according to doctors.

"We are definitely seeing a lot of viruses that aren't flus," said Michael Lewis, MD, a family practitioner with the Facey Medical Group at Northridge Hospital Medical Center. "We know the most common viruses in adults would be rhino virus but we don't really qualify them, meaning we don't check for them."

The hospital's emergency room reports seeing 152 patients with flu-like symptoms, in most cases attributed to viruses other than influenza.  In order to reduce the risk of exposure to other patients, Northridge separates those with symptoms of flu, and like other emergency rooms and urgent care clinics, provides those patients with surgical masks worn over the mouth and nose. 

So far this season, of the 6,184 respiratory illnesses tested for flu, 71, or 1.1 percent, came back positive.  For the week ending December 14, the positive percentage was reported as 1.4 percent. 

Only two weeks later, the positive percentage increased significantly, with 17 of 504 cases, or 3.4 percent, testing flu positive.  Public health officials continue to urge anyone who has not yet gotten the flu vaccination to do so.

The vaccine is 62 percent effective, according to the Centers for Disease Control and Prevention (CDC).

But the vaccine is not crafted to provide protection against RSV or other viruses. Nor is the anti-viral medicine Tamiflu, unless the flu-like symptoms are caused by the actual flu virus, Lewis said.

If you suspect you have true flu, early diagnosis is important for Tamiflu to be effective, Lewis said. If initiated within 48 hours of onset, it can reduce the duration of flu symptoms by two to three days.

California's Department of Public Health intends to release an update "concerning influenza activity in the state" at 10 a.m. Friday.

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