College students are far more likely than others to develop a rare, but potentially deadly, type of bacterial infection, a new study shows.

Students between the ages of 18 and 24 were three and a half times more likely than non-college kids to develop an infection from meningococcus B, which can lead to a life-threatening blood disease, according to the report published Monday in Pediatrics. While there is a vaccine against MenB, few teens and young adults receive it, since it is not one of the immunizations currently recommended for all teens heading into college.

“Although the incidence of MenB is low, it is a serious illness and parents should be aware that a vaccine is available and that it’s something they can talk to their child’s physician about to see if it makes sense to get the vaccine,” said the study’s lead author, pediatrician Dr. Sarah Mbaeyi, a medical officer at the Centers for Disease Control and Prevention.

A vaccine for the four other types of meningococcus (MenACWY) is already recommended for all teens, by the Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts that develop immunization recommendations.

Currently ACIP does not recommended MenB for all teens, which is why Mbaeyi suggests that parents and young people — especially those with college plans — talk over the risks and benefits of the MenB vaccine with their doctor.

The main downside is the cost of the vaccine, experts said, which can run between $300 and $400 for the two shot series.

Though rare, there have been recent outbreaks of MenB. In September officials at San Diego State University reported three students — the number that fits the CDC’s definition of an outbreak — had developed the disease. And in late 2017 an outbreak started in Massachusetts’s five college consortium, with two cases reported in the fall of that year at the University of Massachusetts, Amherst, and a third case in March of 2018 at nearby Smith College.

No one knows for sure why college kids are more likely to develop MenB than others, but it is suspected that they are at greater risk of infection because they may be living in crowded residence halls and regularly mixing with lots of other people, Mbaeyi said.

“The organism lives in the back of the throat,” Mbaeyi explained, adding that approximately 10 percent of people carry it without ever getting sick. “When people are in close contact they can transfer it from one to the other.”

Mbaeyi and her colleagues analyzed three years of meningococcal infection data collected by the National Notifiable Diseases Surveillance System between 2014 and 2016, focusing in on cases in people aged 18 to 24 years.

They identified six MenB outbreaks on college campuses during those years, which accounted for about 32 percent of the total number of cases in college students — the rest were isolated cases.

Comparing the rate of infection in college students to non-students, the researchers determined that college students were 3.54 times more likely than others to become infected.

“If this paper does nothing more than trigger a discussion between the physician and the student and his or her parents then I think it’s already done its job,” said Dr. Ebbing Lautenbach, chief of the division of infectious diseases at the Perelman School of Medicine at the University of Pennsylvania. “Even without a full recommendation by the ACIP, at least people can be thinking about it so they can make an informed decision.”

“It’s a pretty rare disease, but if you get it, it can be devastating,” Lautenbach said. “There’s a high mortality rate and a lot of long-term side effects if you do survive.”

Those effects can include deafness, amputation and brain damage.

Dr. Ira Leeds hopes the new paper does only that and doesn’t spur officials to mandate MenB vaccination for all incoming college students.

High cost of vaccination

Considering how rare the disease is, it’s hard to justify mandating an expense of $300 to $400 for every young person heading off to college, said Leeds, a researcher at Johns Hopkins Bloomberg School of Public Health. Leeds was lead author on a recently published paper arguing that it would not be cost effective to vaccinate all college students.

“It should be an individual decision,” Leeds said.

Ultimately, the value of the new paper is that it’s educating physicians and parents alike, said Dr. Marian Michaels, a professor of pediatrics at the University of Pittsburgh Medical Center and a pediatric infectious disease specialist at UPMC’s Children’s Hospital of Pittsburgh.

“When you look at surveys, you see that only about 50 percent of pediatricians know about the vaccine for MenB and an incredibly small percent — just one third — of family practice doctors know about it,” she said.

“From my standpoint, this is a very safe vaccine and while there isn’t a huge incidence of meningococcal B disease, when it hits, it hits hard and [rapidly],” Michaels said. “Within hours someone could be in the intensive care unit fighting for their lives.”