The World Health Organization recently reported on the alarming rise of “super gonorrhea” that can outmaneuver our current arsenal of antibiotics. In response, researchers are working harder than ever on a gonorrhea vaccine, and a recent study demonstrated some promise for such a vaccine in the future.
The CDC reports that gonorrhea is the “second most commonly reported notifiable disease in the United States,” affecting more than 700,000 Americans every year. The disease is caused by the bacterium Neisseria gonorrhoeae, which spread through unprotected sex with an infected individual. Once in the host, the pathogen can cause to pelvic inflammatory disease, which, for women, can lead to infertility, ectopic pregnancy, and chronic pelvic pain.
"The bacteria that cause gonorrhea are particularly smart. Every time we use a new class of antibiotics to treat the infection, the bacteria evolve to resist them," explained Dr. Teodora Wi, Medical Officer, Human Reproduction, at WHO. "These cases may just be the tip of the iceberg, since systems to diagnose and report untreatable infections are lacking in lower-income countries where gonorrhea is actually more common.”
In response, researchers from New Zealand recently published their results on a gonorrhea vaccine that, for the first time, showed protection against the infection. In about 15,000 young people, the vaccine cut infections by about a third.
Surprisingly, this vaccine for gonorrhea did not start out as a vaccine specific to the Neisseria gonorrhoeae pathogen. Rather, researchers noticed that a vaccine for meningitis B seemed to offer cross protection against gonorrhea too. Upon closer investigation, the scientists noted the bacteria responsible for the two diseases are close relatives that share the same genus (Neisseria meningitides and Neisseria gonorrhoeae). About a third of the teens that were vaccinated against meningitis B between 2004 and 2006 in New Zealand also had protection against gonorrhea that lasted for about two years.
"This is the first time a vaccine has shown any protection against gonorrhea,” said Dr. Helen Petousis-Harris, one of the researchers. "At the moment, the mechanism behind this immune response is unknown, but our findings could inform future vaccine development." She noted that exposure to the pathogen does not naturally induce immunity or resistance; thus, immunity has to come from an external source.
“To control gonorrhoea, we need new tools and systems for better prevention, treatment, earlier diagnosis, and more complete tracking and reporting of new infections, antibiotic use, resistance and treatment failures,” said Dr. Marc Sprenger, Director of Antimicrobial Resistance at WHO. “Specifically, we need new antibiotics, as well as rapid, accurate, point-of-care diagnostic tests – ideally, ones that can predict which antibiotics will work on that particular infection – and longer term, a vaccine to prevent gonorrhea.”