January 16, 2013
CDC Urges Flu Shots for Unvaccinated as Illnesses Surge

AtlantaThe tide of pharmacy customers seeking flu vaccines is unlikely to stem very soon. The CDC reports that most of the country is experiencing high levels of influenza-like illness (ILI) with no peak in sight.

Despite the late date, the CDC still is urging all Americans to be vaccinated against influenza, noting that its protective effects kick in after about 2 weeks. Last flu season, about 20% of adults who were vaccinated went to a retail outlet, primarily pharmacies, for a flu shot, and that number is expected to increase.

“Reports of influenza-like-illness (ILI) are nearing what have been peak levels during moderately severe seasons,” according to Joe Bresee, MD, chief of the Epidemiology and Prevention Branch in CDC's Influenza Division. “While we can't say for certain how severe this season will be, we can say that a lot of people are getting sick with influenza and we are getting reports of severe illness and hospitalizations.”

“Anyone who has not already been vaccinated should do so now,” Bresee said, adding, “And it's important to remember that people who have severe influenza illness, or who are at high risk of serious influenza-related complications, should get treated with influenza antiviral medications if they get flu symptoms regardless of whether or not they got vaccinated. Also, you don't need to wait for a positive laboratory test to start taking antivirals.”

As of the first week of January, the proportion of U.S. patients seeing their health care provider for ILI had been elevated for a month, increasing from 2.8% to 5.6% during that time. During last year's relatively mild season, ILI peaked at 2.2%. In moderately severe seasons such as 1998-1999 and 2003-2004, the ILI peak level was 7.6%, just below the 2009 H1N1 pandemic level of 7.7%.

When will peak occur this year? CDC can't say for sure but points out that during the past 10 regular influenza seasons, ILI remained at or above baseline for an average of 12 consecutive weeks, with a high of 16 weeks. During the pandemic, the proportion of ILI-related visits remained above the national baseline for 19 consecutive weeks.

As of the second week of January, 47 states were reporting widespread geographic influenza activity.

Bresee suggested that the increased severity of the flu season could be related to the predominant circulating type of influenza virus, influenza A (H3N2) viruses, which account for about 76% of those reported. He noted that “typically 'H3N2 seasons' have been more severe, with higher numbers of hospitalizations and deaths, but we will have to see how the season plays out.” On the other hand, the vaccine appears to be a good match, with 91% of the influenza viruses analyzed at CDC included in the 2012-2013 vaccine.

As a second line of defense against influenza, the CDC urges the use of antiviral medications, marketed as Tamiflu and Relenza, as early as possible after patients become ill. Antiviral treatment is recommended for any patients with confirmed or suspected influenza who are hospitalized, seriously ill, or ill and at high risk of serious influenza-related complications, including young children, people 65 and older, those with certain underlying medical conditions and pregnant women.

Recognizing how difficult it is for pharmacists and other health professionals to keep up with fast-changing information during an active flu season, the CDC now offers an application for the iPad, iPhone, or iPod Touch with constantly updated information on national flu activity. The application, which updates automatically when new data is available, also allows highlighting, notes, and bookmarks as well as the ability to share information through social media. An application for Android devices will be added in a future update, according to the CDC.

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