Next month, Princeton University will take extreme measures against a meningitis outbreak that has plagued the campus since early this year. On Monday, the university decided to offer students vaccinations against serogroup B meningococcal bacteria, which has so far spread to six students and one visitor in the past eight months. But the shots they get won't be the ones that are offered to people in the rest of the country: instead, the FDA has approved importing a vaccine that it hasn't yet approved for use in the US, attempting to fill a gap in preventing a deadly disease.

Meningococcal disease, one of the potential causes of bacterial meningitis, is rare in the US; the CDC sees an estimated 1,000 cases a year, and only 500 were reported in 2012. The B variant of it is an even smaller subset, comprising 160 of those 500. But over 10 percent of meningococcal disease cases prove fatal, and between 10 to 20 percent of people who survive do so with brain damage, amputated limbs, or other serious and permanent conditions. The disease can spread through people living in close quarters or sharing saliva — whether that's through kissing or eating with the same utensils — and in many ways, colleges are the perfect breeding ground. In an apparently unrelated case, two students at UC Santa Barbara have also come down with meningococcal disease.

The disease first came to Princeton in March of this year, after a student returned from spring break. For the next several months, new cases slowly added up, and New Jersey's Department of Health officially declared an outbreak after the fourth person was diagnosed in late May. The last straw seems to have been the seventh case on November 8th; while the disease's earlier six victims have recovered, he remains hospitalized. The problem is that although Princeton already requires a meningitis vaccination, it covers serogroups A, C, Y, and W — but not B.

In the US, this still covers the majority of cases. In Europe and Australia, though, meningitis B causes most infections, making a solution more pressing. Bexcero, the first vaccine designed to cover serogroup B, was approved by the European Union in January and by Australia in August; in the US, though, the FDA is still working through the approval process. The CDC and FDA, however, didn't think Princeton should wait for an official US release. "[The] FDA has concluded that the benefits of using the vaccine to prevent meningococcal disease outweigh the risks of possible adverse events," says a CDC statement.

Though Bexcero has never been used in the US, the CDC points to a total of 8,000 people successfully vaccinated abroad. Dr. Art Caplan, head of the Division of Medical Ethics at NYU's Langone Medical Center, says that this still doesn't approach the levels of formal testing the FDA will require: "A big vaccine trial to convince the FDA you really understand the safety and the efficacy of your vaccine is probably 20,000 [subjects]." Caplan says this kind of importation is a rare occurrence, citing the 2001 anthrax scare and the 2004 flu shot shortage as two previous examples where the government considered importing vaccines.

Despite fears of a larger outbreak, Princeton isn't canceling classes or telling outsiders to shun its students. It's also not requiring the unapproved vaccine. All undergraduate students, as well as graduate students living on campus, are encouraged to get the two-dose treatment, with others at the university are receiving shots under certain conditions, and Caplan thinks that may well be all that's necessary in this case. "I think this situation should create the possibility of getting herd immunity" — in which a critical mass of vaccinated students would slow the spread of disease — he says. "If you really had many more cases pop up all of a sudden, you might have to go back and revisit the idea that it shouldn't just be offered but mandated."

Princeton hopes to announce exact dates for the December dose soon, with a second set of shots coming in February. Until then, it's given students recommendations for avoiding spit and coughs — and a pointed reminder that they shouldn't try killing germs with vodka. "Alcoholic beverages do not contain enough alcohol by volume to prevent the spread of illness," says a Q&A page. "The consumption of alcohol may also lead to decreased judgment about sharing objects that come into contact with the mouth."