Gonorrhea is the second most common sexually transmitted disease (STD) in the United States. According to the CDC, a total of 555,608 cases of gonorrhea were reported in 2017 (the last year for which data is available). Gonorrhea is a common infection, and in many cases, affected persons don’t even know they have it, but if left untreated various complications may occur. The latest study found Bexsero vaccine may protect against this prevalent infection.
What is Bexsero?
Bexsero is an FDA-approved vaccine formulated for the immunization of individuals against invasive meningococcal disease caused by Neisseria meningitidis serogroup B. This meningococcal B (MenB) vaccine is approved for use in persons 10 through 25 years of age. Meningitis B is a relatively uncommon but serious disease caused by a bacterial infection in the spinal cord and lining of the brain. The disease progresses quickly, and it can be fatal. Bexsero is the only vaccine for MenB which can be completed fast, in about one month, with just two doses.
Bexsero and gonorrhea
At first glance, Bexsero and gonorrhea have nothing in common, but the latest research says otherwise. A study published in the December 2018 issue of Clinical Infectious Diseases found that the Bexsero vaccine may also offer protection against gonorrhea. So, what led to that study in the first place? Neisseria gonorrhoeae and Neisseria meningitidis are very similar bacteria, and both of them cause serious problems – gonorrhea and meningitis.
However, vaccines for meningitis are distributed routinely while there is no vaccine for the prevention of gonorrhea at this point. The problem becomes even worse if we bear in mind gonorrhea rates are increasing due to antibiotic resistance. A team of scientists at the Griffith University in Gold Coast, Australia carried out a study to assess the cross-reactivity of the Bexsero vaccine on gonorrhea-causing bacteria.
Bexsero contains a MeNZB OMV component, so researchers performed a bioinformatic analysis to assess the similarity of Bexsero antigens to gonococcal proteins. Findings revealed that there is, indeed, a high level of sequence identity between the MeNZB OMV component and Bexsero OMV antigens and gonococcal proteins. MeNZB is a New Zealand vaccine for meningitis B prevention.
Although the study was conducted on rabbits results, apply to humans too. Scientists who worked on this research explain that vaccine development for gonorrhea has been very difficult, but they were able to confirm that a vaccine formulated to tackle similar bacteria can generate antibodies in humans that are able to target this prevalent STD.
A study from Australia could pave the way for the development of a vaccine for gonorrhea or, at least, give a few ideas on how to protect people from this widespread STD as it’s becoming antibiotic-resistant lately. Serum from humans vaccinated with Bexsero recognizes the gonococcal counterparts of the antigens thus supporting the previous findings that the MeNZB vaccine could have induced protection against gonorrhea. The NHBA antigen, found in Bexsero but not in MeNZB, is conserved in strains of gonorrhea-causing bacteria and it is strongly targeted by serum from people vaccinated with Bexsero.