A sixth case in a meningococcal disease outbreak on the Corvallis campus of Oregon State University prompted school officials to require all students under age 25 be vaccinated for meningococcal B disease by Feb. 15.

School officials did not detail how they would enforce the vaccination requirement but indicated they would have rules that could not be easily circumvented.

“If you are not vaccinated against this disease and you are a student on that campus, you are at risk for meningococcal infection,” said Dr. Paul Cieslak, medical director for communicable diseases and immunizations at the Oregon Health Authority Public Health Division. “We do feel that now, because there is a break between classes, that this is the best time for students to get vaccinated.”

Meningococcal disease is not a highly contagious disease, but it has a 100 percent fatality rate without antibiotic treatment. Even with antibiotics, some 15 percent of those infected will die. Another 15 to 20 percent will incur long-term consequences such as brain damage or the loss of fingers or limbs.

“This disease can progress from sort of feeling like you have the flu and feeling crummy to being catastrophic very quickly,” said Charlie Fautin, deputy director of the Benton County Health Department. “We’ve been very fortunate in this outbreak. The five previous students all made full recoveries.”

The outbreak began in November 2016 when two students were hospitalized with meningococcal B disease in less than a week. A third student was diagnosed in March, prompting a formal declaration of an outbreak.

School officials organized two mass vaccination clinics in the spring and three more this fall. Vaccination efforts mainly targeted students with frequent close contact, including those living in residences and group housing, and on athletic teams.

The school already had a requirement to get a meningococcal vaccine that protects against the A, C, Y and W strains of the disease. But that vaccine offers no protection against the B strain that is currently circulating on the Corvallis campus.

The school revised its vaccination guidelines for the current school year, requiring all incoming freshmen and transfer students to be vaccinated specifically for meningococcal B disease by the first week of November in order to register for winter term classes.

But a fourth student was diagnosed in October and a fifth in November while home for Thanksgiving outside of Corvallis. The sixth case was a 21-year-old student hospitalized Dec. 17 while visiting family. Testing to confirm the strain has not been completed.

“We realize now, with this case which involves an older student not living in congregate housing, like residence halls or group living, that we need to up our requirements,” said Steve Clark, OSU vice president for university relations and marketing, who has spearheaded the school’s response to the outbreak.

The standard approach with a single case of meningococcal disease is to provide antibiotics to those in close contact with the infected person. But as the outbreak spread across the campus, with no obvious link between the six cases, officials had to broaden the scope of their interventions.

“The problem is the cat’s out of the bag. It’s spread completely through the campus,” Cieslak said. “It’s not like it’s in one dorm, one fraternity or one athletic team. Therefore the only way to protect people is to get them all immune.”

Meningococcal disease can include meningitis, an infection of the fluids that line the brain and spinal cord. Meningitis symptoms can include fever, headache, stiff neck, nausea and confusion. The bacteria can also cause a blood infection, known as meningococcemia, with symptoms such as fever, shaking chills, rash, fatigue, severe aches and pains and rapid breathing.

The disease is spread when a healthy person comes in close contact with an infected person’s nose or throat fluids, such as droplets from a sneeze, spit or saliva. It occurs most often among large groups of people living in close quarters, such as in university residences, group housing or fraternities or sororities.

The bacteria are being spread from student to student on campus with most infections not causing recognizable symptoms.

“We don’t know who they are, and we don’t know who it’s going to strike next,” Cieslak said.

Public health officials urged families and friends to be on the lookout for symptoms of meningococcal disease, and recommend that doctors have a low threshold for suspecting the condition, particularly in OSU students.

In 2015, the University of Oregon had a meningococcal B outbreak affecting six students, one of whom died. The university held four mass vaccination clinics with the goal of immunizing all undergraduate students, but according to public health officials, only an estimated 6 percent of students were fully vaccinated.

“The best prevention is vaccination,” Fautin said. “This is the proven way to disrupt these kinds of outbreaks and our uptake unfortunately has not been as great as we would like.”

Two brands of meningococcal vaccine are licensed for use in the United States from age 10 to 25. Bexsoro requires two doses given at least one month apart for full coverage. Trumemba requires three doses, with follow-up doses one month and six months after the first.

Cieslak said a single dose of either vaccine is likely to provide only 40 to 60 percent effectiveness, compared to 80 to 90 percent effectiveness for the full series. The vaccines are not interchangeable so follow-up doses should be of the same brand.

Doctors and county health officials in Central Oregon have been on alert for cases, particularly those involving college students. Deschutes County Health Services offers the vaccine and is compiling a list of pharmacies that offer it, including Rite Aid, Walgreens, Fred Meyer and Safeway on Century Drive. St. Charles Health System offers the vaccines in its family care and school-based clinics.

The vaccine costs about $300 but is covered by insurance plans. Some university students, however, had trouble getting insurance coverage for the vaccine on campus because the providers were out-of-network. The Oregon Legislature passed House Bill 3276 to address that issue during outbreaks, and the governor signs the bill into law in August.

The holiday break, however, often brings students back to their familiar doctors and pharmacists, or back home where parents can ensure their children get vaccinated. Cieslak stressed the importance of prevention as well as timely treatment if symptoms arise.

“It’s a nasty virulent bacterium that can affect even perfectly healthy people,” he said. “And if you have it in your spinal fluid and you don’t get antibiotics promptly, you are going to die.”

—Reporter: 541-633-2162, mhawryluk@bendbulletin.com