Flu Hospitalizations Trending in Young Adults

H1N1 virus dominating flu season in US with more influenza hospitalizations in younger adults

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) As the new year begins, a more detailed picture of the current flu season is developing. The season is now in full gear with over half of US states reporting widespread flu activity.

The Centers for Disease Control and Prevention (CDC) releases a weekly report summarizing influenza activity in the US.

The latest report, which updated information to include the week ending January 4, 2014, showed that over half of reported flu hospitalizations occurred in adults under the age of 65 years old.

"Talk to your doctor about an influenza vaccine."

During the week that began on December 29 and ended on January 4, CDC reported that 35 states were experiencing widespread flu activity — an increase from 25 states experiencing widespread activity during the previous week. The latest report also noted that 20 states were reporting high levels of other flu-like illness.

Most of the influenza viruses being seen are of the H1N1 type of virus — the same type of virus that caused many illnesses in 2009.

CDC analyzed 2,486 influenza-positive tests during the week ending January 4. Nearly all of these (2,421 tests) were influenza A viruses. And of the 1,391 influenza A viruses that were further analyzed, 98.6 percent were found to be 2009 H1N1 viruses.

CDC collects data on flu hospitalizations from 13 different states. From this available data, 2,622 confirmed hospitalizations related to the flu have been reported since the beginning of October, which amounts to a rate of 9.7 hospitalizations for every 100,000 Americans.

Of these hospitalizations, over half (61.6 percent) occurred in patients between the ages of 18 to 64 years old.

"More commonly, most flu hospitalizations occur in people 65 and older," noted CDC. "This pattern of more hospitalizations among younger people was also seen during the 2009 H1N1 pandemic."

The deaths of 10 children related to the flu have been reported across the country this season — four of which were reported during the week ending January 4. CDC noted that the proportion of overall flu-related deaths reported so far remain below epidemic levels.

"As was seen in the 2009 H1N1 influenza pandemic, the majority of persons adversely affected by influenza were younger adults, ages 18-64.  Although more severe disease is generally seen in the older and immunocompromised population, with H1N1 the target population is usually different," said E. Lee Carter, RPh, Clinical Pharmacy Specialist at the Department of Veterans Affairs in Prestonsburg, Kentucky.

"Younger adults and children are at higher risk with H1N1 than with other strains of influenza. Therefore, public education regarding vaccination is paramount to reducing adverse events in this age group. Patients at higher risk of adverse outcomes (as compared to the general population) include chronic lung disease (including asthma), immunosuppressive conditions, pregnancy, diabetes, and obesity," Carter told dailyRx News.

Though the season has been gearing up for several months, CDC stressed that it is not too late to receive a flu vaccination.

"Anyone aged 6 months and older who has not gotten a flu vaccine yet this season should get one now," recommended CDC. "All flu vaccines are designed to protect against H1N1 viruses."

According to Carter, "All the available CDC-approved influenza vaccines have activity against the H1N1 flu strains. Contrary to belief, it is still not too late to receive the vaccine. I would encourage everyone to discuss with their health-care provider and/or pharmacist about the benefits of flu vaccination."

Review Date: 
January 13, 2014
Last Updated:
January 14, 2014