Update on 2014–2015 seasonal flu

The 2014-2015 influenza vaccine may not provide complete protection from the most common flu strain now in circulation, but evidence suggests that it still may reduce the severity and duration of symptoms, UCI Health infectious disease expert Dr. Shruti K. Gohil said.

And people who do develop flu-like symptoms – especially those with compromised immune systems – should ask their primary care provider if they are candidates for the antiviral medications Tamiflu and Relenza.

The problem is that this year’s vaccine is not an ideal match for the influenza A type that is in wide circulation this flu season.

“When the flu vaccine is not an ideal match, it’s really important that clinicians consider the use of antiviral medications for patients who have symptoms of influenza – especially among those at highest risk of developing serious complications,” Gohil said. Such patients include the elderly and people with chronic obstructive pulmonary disease.  

“But antiviral medication is only effective when taken in the first few days,” added Gohil, associate medical director for epidemiology and infectious diseases at UC Irvine Medical Center and an assistant professor at UC Irvine School of Medicine. “If you feel like you have the flu, ask your doctor right away whether you should consider taking Tamiflu or Relenza.”

Seasonal flu activity has been sporadic in California, where health officials say the first confirmed cases began appearing in November. However, influenza has spread widely across at least 14 states, including Colorado, Delaware, Florida, Georgia, Illinois, Kentucky, Louisiana, Maryland, Minnesota, New York, North Carolina, Ohio, Pennsylvania, and Texas. According to the U.S. Centers for Disease Control and Prevention, at least seven children had died of influenza-related causes by Nov. 30.

As cases mounted, health authorities discovered that more than 50 percent of flu sufferers tested carried a more virulent strain of the influenza A virus, one that had shifted genetically from the strain used to make the current vaccine. The process, called antigenic drift, occurs when a virus mutates over time, from patient to patient.

The mutated virus began appearing in March 2014, long after scientists had selected the influenza A type to include in the 2014-2015 vaccine, which began production in February 2014. This season’s vaccine also contains strains of influenza type B and the influenza A H1N1 type, which have been circulating at very low levels, according to the CDC.

“Although this year’s vaccine doesn’t match up perfectly with what’s out there, our experience has shown that people who have been vaccinated have fewer hospitalizations, fewer doctor visits and less time taken away from work – indicators that the vaccine is still providing some protection,” Gohil said. “The vaccine is still working against the other flu types and it may help strengthen your immune response to the primary circulating strains even if it is not a 100 percent match.”

The flu season usually begins to peak in January, so it’s still a good idea to get a flu shot, Gohil said. In the meantime, she recommends practicing some basic health rules:

• Wash your hands often with soap and water or an alcohol-based hand rub
• Drink plenty of fluids, eat nutritious foods, take vitamins and exercise
• Avoid close contact with people who are ill

If you do develop flu-like symptoms, you should:

• Stay home and limit contact with others, except to seek medical care
• Take antiviral drugs if your healthcare provider prescribes them
• Do not return to work, school or regular activities until the fever has subsided for at least 24 hours without medication