Nearly half of all those hospitalized due to complications from influenza in the U.S. this season are obese, leading medical professionals to wonder if the influenza-obesity combination makes the virus particularly dangerous.
According to the Center for Disease Control and Prevention (CDC) report released on Jan. 4, 46 percent of adults admitted to hospitals for influenza were also obese. An expert on the virus for the CDC, Joseph Bresee, says that while it is possible that that overall percentage could decrease as the season goes on, it is a high number at this point.
A medical epidemiologist in North Carolina agrees that the number is high. Zack Moore, of the state’s Division of Public Health, says that in a typical year the percentage of hospitalized influenza patients who are also obese is significantly lower, in the 20 to 30 percent range.
Medical researchers and professionals don’t have an absolute explanation for why obesity seems to be a factor for increased risk when the influenza virus is contracted, but they do seem to generally believe that the link may be due to the fact that obesity is “known to alter the immune response.”
Obesity also seems to be linked to “respiratory restrictions,” and pneumonia, a known respiratory problem, is also the most common reason that those with influenza become hospitalized. The most severely affected may even be admitted to intensive care units where they can be placed on a ventilator.
The CDC’s Bresee reports that a similar pattern was identified in 2009, the year of the H1N1 pandemic. A study linking obesity and an increased risk of complications from influenza was conducted following that flu season. That study found that for obese people with no additional underlying chronic medical conditions, the risks for serious complications resulting from influenza were about the same as for those of a healthy weight. However, when obesity was coupled with another underlying factor such as diabetes or hypertension, the risk complications and hospitalization due to influenza increased dramatically.
The study resulted in new, stronger recommendations to the medical community that those who are obese should be strongly advised to seek out an annual influenza vaccine and that they should be treated with antiviral medication without delay upon presenting with any flu-like symptoms during the peak season.
As influenza season is in full force around the nation, the danger it presents should not be underestimated by anyone, obese or otherwise. It has already resulted in more than 2,600 hospitalizations and dozens of deaths, including the deaths of ten children. In past years, hospitalizations and complications related to influenza have been seen most frequently in those over the age of 65 or those under the age of 5. This year, in addition to an increased number of hospitalized obese patients, there has been an increase in hospitalization among adults in general between the ages of 18 and 64. This pattern of younger people becoming severely ill from influenza is also similar to that which occurred during the 2009 H1N1 pandemic.
The CDC is still encouraging people to get vaccinated against influenza this season, as there are several months to go before the threat of the virus is significantly lowered.
By Michele Wessel