ARTICLE IN BRIEF
The article discusses an outbreak of meningitis B at two college campuses and the federal response to it.
An outbreak of meningitis B — a meningococcal meningitis — at Princeton University and a cluster of cases at the University of California, Santa Barbara (UCSB), have prompted US health officials to take emergency steps to protect students, including the use of an unlicensed vaccine at Princeton that has been approved in Canada and the European Union, but not the United States.
In the first three days of a vaccination program against a prolonged outbreak of the disease at Princeton, where eight cases have occurred since last March, almost 5,000 students were inoculated with Bexsero®, a vaccine manufactured by Novartis Pharmaceuticals, headquartered in Basel, Switzerland.
The US Food and Drug Administration (FDA) approved the unlicensed vaccine under a New Drug Application (NDA) filed by the Centers for Disease Control and Prevention (CDC) amid concerns of the outbreak spreading.
According to the CDC, the vaccine covers 91 percent of circulating strains of meningitis B, and lab tests have confirmed that the vaccine will help protect against the strain of meningococcal bacteria (ST409) at Princeton.
There have been four cases to date at UCSB, and while there have been no fatalities associated with infection at either school, one student at UCSB underwent amputation of both feet, and several students at both schools had to be hospitalized.
The vaccine is not being offered at UCSB because the number of cases does not meet the CDC's threshold definition of an outbreak, according to James J. Sejvar, MD, a neuroepidemiologist at the CDC's Division of High-Consequence Pathogens and Pathology.
Although the meningococcal serotype is the same at Princeton and UCSB — serotype B — the strains are unique and unrelated based on sequencing data, according to Dr. Sejvar. “The serotype at Princeton is similar but unrelated to the strain at UC Santa Barbara, so it was decided to approach the cases in California a little differently,” he told Neurology Today in a telephone interview.
“We generally do not recommend vaccination to control these types of outbreaks,” he noted, adding that 98 percent of meningitis cases in the US are sporadic rather than occurring in clusters.
At UCSB, health officials have instead performed prophylaxis of the at-risk population with antibiotics.
While clusters of meningitis B have occurred in the past, they almost always occur in institutional settings like colleges, military barracks, and prisons where close personal contact is unavoidable, Dr. Sejvar explained.
“Laboratory workers and bacteriologists are also at risk if they are exposed to higher, concentrated doses of meningitis B.”
In the general population there are three groups who are at higher risk from exposure — children under 5 years of age, adolescents between the ages of 11 and 18 years, and individuals who are 65 or older and generally have weaker immune systems, according to Dr. Sejvar.
Meningitis B kills about 1 in 10 people who contract it, and can also cause severe disability, including paralysis, mental impairment, nervous system problems, and hearing loss. In addition, infected individuals can also develop meningococcal-associated septicemia.
Symptoms can appear and progress very rapidly — in a matter of days — which makes it important that medical attention is sought immediately if symptoms occur.
So far the efforts at Princeton and UCSB appear to be working, although it is impossible to say if and when the outbreaks will stop at the schools or elsewhere, Dr. Sejvar told Neurology Today.
“It is reassuring that we have not had any more cases so far, and these outbreaks tend to be limited, even in institutional settings,” he said.
According to the CDC, students traveling for the holidays present little risk of spreading illness to friends and family members however the agency has also said that it expects some new cases in the months ahead.
VACCINE DEEMED SAFE
The use of an unlicensed vaccine in the U.S. is unprecedented, but officials at the CDC and the Food and Drug Administration determined that its safety had been confirmed in multiple studies that led to European approval of the vaccine, as well as the severity of the illness and the risk of it spreading.
The European Union approved it in January 2013, Australia in August 2013, and Canada in early December. More than 8,000 infants, children, adolescents, and adults have been safely vaccinated as part of the studies and post-marketing monitoring, according to the CDC.
The vaccine is currently in phase 2 clinical trials in the US as part of a broader Novartis vaccine against multiple strains of meningitis.
Meningitis B bacteria are harbored in the nose and throat, and infection typically is spread through respiratory excretions and saliva. Some infected individuals are asymptomatic carriers, and because initial symptoms are similar to those of a bad cold or the flu, early diagnosis can be difficult. The infection can progress very quickly — in a matter of days — into a seriously disabling or life-threating state if medical care is not sought.
According to the CDC, symptoms may include sudden onset of a high fever, headache, stiff neck, nausea, vomiting, rapid breathing, or a rash. In a special bulletin on its website, the agency noted that “it is important to remember that someone with meningococcal disease may have a high fever and no other symptoms.”
College campuses are especially suitable for the spread of meningitis because many students live in close proximity, especially in fraternities and sororities where the sharing of cups, glasses, and cigarettes, as well as kissing, can transmit the disease, as can being near to an infected person who coughs or sneezes.
In a press briefing, Amanda Cohn, MD, a pediatrician and an expert in meningococcal disease at the CDC, told reporters that while the illness can prove very serious, it should not raise undue anxiety among students or parents.
“Fortunately, meningococcal bacteria are harder to spread than viruses that cause things like the flu or respiratory viruses, and they don't live long outside the body.”
Moreover, the bacteria are not spread by casual contact, she noted, adding that around 10 percent of individuals across the US carry the bacteria in the back of their nose or throat and never develop symptoms.
‘WAIT AND SEE’
Kenneth L. Tyler, MD, the Reuler-Lewin Family professor and chairman of the department of neurology at the University of Colorado School of Medicine, in Aurora, is an expert in infectious diseases of the central nervous system.
“Even though there is some controversy about access and availability of the vaccine, I think the CDC and the FDA responded well to the outbreaks,” he told Neurology Today in a telephone interview.
“It is interesting that the vaccine was not also made available at UCSB, and there is a lot of concern among parents — why the Princeton students got it and UCSB did not.”
Determining how many people have been exposed to the two strains is impossible, added Dr. Tyler, who is an associate editor of Neurology Today.
“Meningitis B is very tricky because we have asymptomatic people who are carriers, so it is possible that there may be more infections. I doubt this will happen at Princeton, because the outbreak began last March, only eight students developed the disease, and there have been no new cases. And with the vaccination program, most of the at-risk student population is no longer very susceptible. But there is no way of telling, so we will also just have to wait and see.”
Dr. Tyler noted that vaccines have dramatically altered the epidemiology of bacterial meningitis, particularly with more common forms of meningitis — such as Streptococcus pneumoniae and Haemophilus influenzae. Haemophilus influenzae (H. flu) Type B (Hib) has dropped precipitously in importance, he said, and S. pneumoniae has also been dramatically reduced since vaccines were available. “Many of the cases we see of this are due to strains not covered by the vaccine.”