The Benefits of Bexsero at Princeton

In the past few weeks, Princeton University has found itself a hot topic in the media for what has now been described as an outbreak of meningitis B¹. Although Princeton currently requires all students to be vaccinated against meningitis, the current vaccine does not protect against serogroup B. There is no currently approved vaccine against serogroup B, but Bexsero, a Novartis-produced vaccine that has been licensed in Europe and Australia, has been granted special approval for use on our campus, due to the nature of the outbreak.

It has been particularly difficult to make a vaccine against meningitis serogroup B. Bacteria have sugar-based coatings, and most vaccines are made using this coating to induce a response from the immune system. Then, when the bacteria enter the bloodstream, the immune system will recognize that same sugar coat and produce antibodies, prompting a quick and effective response. However, for some reason, the coating of meningitis B bacteria does not provoke an immune response; it seems that meningitis B bacterial cells resemble human cells^2,3. To combat this problem, Novartis researchers used a technique known as reverse vaccinology. With this strategy, instead of cultivating the pathogen in a lab to develop a vaccine, the pathogen is examined via a computer for vaccine possibilities. The Bexsero vaccine uses three recombinant proteins and outer membrane vesicles as its means of identifying the strain^4,5.

The benefit of Bexsero, at its simplest, is obvious: “its ability to protect against invasive group B meningococcal disease.”^6,7 Meningitis B causes most of the cases in nations including the United States. Inoculating a large portion of the population in a group, such as the Princeton student body, that is likely to fall ill can have far-reaching effects. It protects the individuals vaccinated, obviously. In a study conducted by The Daily Princetonian, 259 students were interviewed about their vaccination plans, and 197, or 76%, said that they planned to take the vaccine⁸. If a similar percentage of the entire student population were to actually receive the vaccine, then approximately three-quarters of the student body would be directly protected from meningitis B infection.

However, more than 76% of the student body would be offered protection through herd immunity. Herd, or community immunity, exists when a large percentage of a population is vaccinated or otherwise protected against a given disease. In a non-inoculated population, even one person contracting an infectious disease, such as meningitis B here on our campus, can cause it to spread relatively quickly, as people become infected and pass it on to those around them, who in turn spread it further. However, if a large amount of the population is protected, this cycle halts. Some non-vaccinated students may fall ill, but the disease will be contained because exposed peers will likely have been vaccinated and thus prevent it from spreading outward in waves⁹.

The vaccine has proven effective in several tests. In studies of adolescents, high percentages (86-97%) of the test subjects tested positive for protective antibodies after two doses^10,11. Princeton University is recommending a similar schedule, with the initial dose of Bexsero in early December and a booster dose in February¹². Adults were also shown to have tested positive for antibody titers after two doses¹³.

Given the nature of Princeton’s outbreak, vaccinating seems to be a highly favorable action to make. At a highly academic institution such as this, it is likely that a sick student would still attempt to attend classes, exposing their peers in close quarters, including dining halls. Furthermore, faculty members could also become infected. This would necessitate cancelling their classes while they recover, which would be detrimental to many. Their families, too, would be put at risk. Being inoculated before the holidays, as Princeton is recommending, would help prevent students from possibly bringing meningitis back to their hometowns, where it could be then passed to different schools. By giving students the option to take the meningitis vaccine, the university would simultaneously quell the fears of those who had been worried, while not imposing on those who feel no need for such measures. And it would help prevent further cases of meningitis from occurring.

References

1. Meningitis information. Princeton University. Retrieved from http://web.princeton.edu/sites/emergency/meningitis.html

2. New meningitis B vaccine gets go-ahead. NHS choices. Retrieved from http://www.nhs.uk/news/2012/11November/Pages/Meningitis-B-vaccine-gets-go-ahead.aspx

3. Retrieved from http://www.meningitis.org/menb-vaccine

4. Bexsero: Targeting meningococcal serogroup B. Novartis. Retrieved from http://www.novartisvaccines.com/downloads/meningococcal-disease/Bexsero_Fact_Sheet.pdf

5. Rappuoli R. Reverse vaccionology, a genome-based approach to vaccine development. Vaccine. 2001 Mar; 19(17-19):2688-91.

6. Kaaijk P, van der Ende A, Luytjes W. Routine vaccination against MenB: Considerations for implementation. Hum Vaccin Immunother. 2013 Oct; 10(2). [Epub ahead of print]

7. Retrieved from http://www.ema.europa.eu/docs/en_GB/document_library/Summary_of_opinion_-_Initial_authorisation/human/002333/WC500134836.pdf

8. Sheehan J, Amoakhu K. 76 percent of students say they plan to get meningitis vaccine. The Daily Princetonian. Retrieved from http://dailyprincetonian.com/news/2013/11/76-percent-of-students-say-they-plan-to-get-meningitis-vaccine/

9. Community immunity (“herd” immunity). National Institute of Allergy and Infectious Diseases. Retrieved from http://www.niaid.nih.gov/topics/pages/communityimmunity.aspx

10. http://ec.europa.eu/health/documents/community-register/2013/20130114125155/anx_125155_en.pdf

11. Sntolaya ME, et al. Persistence of antibodies in adolescents 18-24 months after immunization with one, tow, or three doses of 4CMenB meningococcal serogroup B vaccine. Hum Vaccin Immunother. 2013 Jun; 9(11). [Epub ahead of print]

12. Tseng, E. Princeton to sponsor two rounds of emergency meningitis vaccinations pending final CDC approval. The Daily Princetonian. Retrieved from http://dailyprincetonian.com/news/2013/11/breaking-princeton-to-provide-unlicensed-meningitis-b-vaccine-in-december/

13. Carter, NJ. Multicomponent meningococcal serogroup B vaccine (4CMenB; Bexsero): a review of its use in primary and booster vaccination. BioDrugs. 2013 Jun; 27(3):263-74.