When healthy habits become risky business

January 22, 2014 by Angela Herring, Northeastern University
Ravi Sundaram and Rajmohan Rajaraman used their expertise in computational modeling to study the spread of infectious diseases across a network. Credit: Mariah Tauger.

"When people take precautionary measures, their behavior often changes as a result," said Ravi Sundaram, an associate professor in the College of Computer and Information Science at Northeastern University. For example, people wearing seatbelts may drive faster, people who've received flu shots may skip washing their hands before eating, and those who've been vaccinated against sexually transmitted diseases may tend to engage in more risky behavior.

But how do these behavioral changes affect a contagion's spread when the precaution is not foolproof? This is precisely the question that Sundaram and his colleague, professor Rajmohan Rajaraman asked in research recently published in the Journal PLOS ONE.

The duo used network science techniques to look specifically at the influenza vaccine, which has a 20 to 40 percent chance of failing, and the HIV/AIDS antiretroviral, which is unsuccessful 25 to 75 percent of the time.

Given these statistics, Rajaraman said, "if the level of risky behavior exceeds a certain threshold, then you arrive at some strange scenarios in which the more you intervene the worse you're making it."

The flu virus only requires that one person make a poor decision before it jumps to another host. In this case, if the are low, then increased vaccination will tend to make the problem worse. This anomaly does not occur, however, when a large fraction of the population is vaccinated, which will outweigh the negative impacts of risky behavior.

However, things aren't this simple with STDs, which require two parties' participation to be transmitted from one host to another. Here, risky behavior is overcome by increased vaccinations—but only to a point. Using a computational model based on data from the New River Valley in Virginia, the researchers found that after about 40 percent of the population was vaccinated, the tables turned. Now the risky behavior outweighed the positive impacts of the vaccine.

"What happens in the HIV case is that since the risky behavior requires consent on both sides, the number of risky interactions for low levels of vaccination is still very small," said Rajaraman. "So you benefit with increased vaccination. But this may no longer hold at high levels of vaccination." That is, one person's risky intention will not translate into risky behavior until the second party is also vaccinated.

The critical takeaway of the research, Sundaram said, "is that we have to have some kind of behavioral intervention that is coordinated with the medical intervention. So we tell people go get a flu shot, but then you also need to accompany it with some kind of in which you tell people to be aware that it isn't perfect."

The research is part of an ongoing collaborative study with computer scientists at Virginia Tech and epidemiologists at Pennsylvania State University in which the team is looking at similar problems across a variety of contagions.

The results, if confirmed in real-world settings, could have significant policy implications, said epidemiologist Stephen Eubank, one of the team's collaborators at Virginia Tech University.

Explore further: More kids protected from flu; CDC says keep it up

More information: Rajaraman R, Sun Z, Sundaram R, Vullikanti AKS (2013) Network Effects of Risk Behavior Change Following Prophylactic Interventions. PLoS ONE 8(8): e64653. DOI: 10.1371/journal.pone.0064653

Related Stories

More kids protected from flu; CDC says keep it up

September 26, 2013
More children than ever got vaccinated against the flu last year, and health officials are urging families to do even better this time around.

Text messaging boosts flu vaccine rates in pregnant women

January 11, 2014
A study by researchers at the Mailman School of Public Health evaluated the impact of text messaging reminders for influenza vaccine in a low-income obstetric population. The findings showed that sending text messages to ...

Time to get a flu shot, CDC says

September 30, 2013
More than half of the children in the United States were vaccinated against influenza during the 2012-13 flu season, along with more than 4 in 10 adults, according to the Centers for Disease Control and Prevention. Overall, ...

Book debuts brain models of risky decision-making

December 11, 2013
Risky choices – about sex, drugs and drinking, as well as diet, exercise, money and health care – pervade our lives and can have dire consequences. Now, a new book aims to help us understand the neural roots of bad decisions. ...

HPV vaccine does not appear to encourage risky sexual behavior

December 13, 2011
Despite some assumptions to the contrary, young women who receive recommended vaccinations to prevent human papillomavirus (HPV) infection and associated cancers do not engage in more sexually risky behavior.

Anti-swine flu vaccination linked to increased risk of narcolepsy in young adults

January 21, 2014
Pandemrix is an influenza vaccination, created in 2009 to combat H1N1, known as Swine Flu. Now, a team of Swedish clinicians testing the vaccine for links to immune-related or neurological diseases have linked Pandemrix to ...

Recommended for you

Americans are getting more sleep

January 19, 2018
Although more than one in three Americans still don't get enough sleep, a new analysis shows first signs of success in the fight for more shut eye. According to data from 181,335 respondents aged 15 and older who participated ...

Wine is good for you—to a point

January 18, 2018
The Mediterranean diet has become synonymous with healthy eating, but there's one thing in it that stands out: It's cool to drink wine.

Sleep better, lose weight?

January 17, 2018
(HealthDay)—Sleeplessness could cost you when it's time to stand on your bathroom scale, a new British study suggests.

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

Can muesli help against arthritis?

January 15, 2018
It is well known that healthy eating increases a general sense of wellbeing. Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now discovered that a fibre-rich diet can have a positive influence ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.