Steering clear of people who are coughing and sneezing is one way to prevent catching the flu. Avoiding e-cigarettes may be another, new research suggests.
In a small study including smokers, e-cigarette users and non-smokers, researchers saw that both traditional cigarette smokers and "vapers" were more susceptible to flu.
Women have greater risk
But cigarettes and e-cigarettes appeared to boost flu risk through different pathways.
"E-cigarettes can alter your response to viral infections and may make you more susceptible to influenza," said the study's lead author, Meghan Rebuli. She's a postdoctoral research associate at the University of North Carolina at Chapel Hill's Center for Environmental Medicine, Asthma and Lung Biology.
Rebuli added that the researchers found that men and women responded differently to e-cigarettes, and women may have an even greater risk of infection with flu if they vape.
E-cigarettes are small electronic devices that heat a liquid to make an aerosol to be inhaled or "vaped". The liquid may contain nicotine, flavouring and other chemicals, according to the US Centers for Disease Control and Prevention.
Because e-cigarettes contain fewer chemicals than tobacco cigarettes, they're generally considered somewhat safer. E-cigarettes can be beneficial if they help people stop smoking tobacco cigarettes, the CDC says. But people who haven't smoked shouldn't start using e-cigarettes, they advise.
Disrupting immune response
More research needs to be done on any potential health effects from e-cigarettes, the CDC noted.
And that's where this study comes in.
"We know that cigarette smoking increases your risk of infection with influenza, and we were curious whether e-cigarettes would also disrupt the normal immune response," Rebuli said.
The study included nearly 50 people – 14 e-cigarette users, 13 tobacco cigarette smokers and 20 non-smokers. On average, participants were slightly overweight and in their mid to late 20s. But the e-cigarette vapers were slightly younger, with an average age of 23.
Rebuli noted that many of the e-cigarette users were former tobacco smokers, but they had to have been off of tobacco cigarettes for at least a year to be in the study. E-cigarette users had to have vaped for at least 30 days, though most had been doing so for a few years, according to Rebuli.
The researchers also required that e-cigarette users in the study had to puff on an e-cigarette at least 18 times daily. Many did more than that, with some puffing several hundred times a day, Rebuli said.
E-cigarettes do affect immune system
All of the volunteers were exposed to a "live attenuated influenza virus". Rebuli said this particular virus only replicates in the nose.
When the investigators looked at how the immune system responded to the virus, they saw differences in e-cigarette and regular cigarette smokers compared to the non-smokers. But the changes differed depending on the method of smoking.
Rebuli said it's not clear exactly how e-cigarettes led to the changes in the immune response, just that they did. And while the researchers didn't look at whether or not a flu infection might be more severe in people who use e-cigarettes, "it's a possibility," she said.
Dr Richard Stumacher is chief of pulmonary and critical care medicine at Northern Westchester Hospital in Mount Kisco, New York. He said this study is an important step in better understanding the effects of e-cigarette research.
"What's important to glean from this preliminary information is that there is evidence that e-cigarettes do affect the immune system in a way that's directly related to a person's ability to fight an infection," Stumacher said.
Findings from the study are scheduled to be presented at the American Thoracic Society meeting in Dallas. Findings presented at meetings should be viewed as preliminary until they've been published in a peer-reviewed journal.
Image credit: iStock