Scientists have not been able to develop a vaccine against the sexually transmitted disease gonorrhea, despite working toward one for more than 100 years.

However, they may have stumbled onto something that could provide clues to advance the development of such a vaccine.

Decades ago, in the late 1990s, a strain of meningitis B was reaching epidemic proportions in New Zealand. A vaccine, MeNZB, was developed to protect young people who were at the highest risk of getting this particular type. It did not provide protection against any other strain.

Between 2004 and 2006, MeNZB was given to anyone under the age of 20. Babies and preschoolers were routinely immunized until 2008. People with a high medical risk continued to get the vaccine until 2011. Once the epidemic was over, the vaccination program was stopped.

However, scientists noticed that the meningitis vaccine also seemed to offer some protection against gonorrhea. A study published in the Lancet last month showed that one-third of the people who had received MeNZB did not get gonorrhea, compared to a control group who was not inoculated. The lead author noted that the bacteria causing both diseases share between 80 and 90 percent of their primary genetic sequences.

Dr. Steven Black, an infectious disease expert at Cincinnati Children’s Hospital, noted, “This is the first time it’s been shown that you could have a vaccine that would protect against gonorrhea. And if these results are confirmed in another setting, that would mean that it would be very reasonable … to go forward with developing perhaps a more targeted vaccine.” Black’s comments were published in the current issue of JAMA, the Journal of the American Medical Association.

The World Health Organization reports that gonorrhea is becoming harder, and sometimes impossible, to treat, warning that it could become incurable in the not-too-distant future. At the moment, there no new antibiotics being developed to treat this disease.

“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,” according to Dr. Teodora Wi, a medical officer involved in human reproduction at the WHO, quoted in a news release from the UN agency.

The U.S. Centers for Disease Control and Prevention (CDC) reports that gonorrhea is the second most commonly reported notifiable disease in the United States. All known cases must be reported to the CDC, but officials there estimate that they are notified of fewer than half of the 800,000 new cases each year.

Women may not have any symptoms, but untreated gonorrhea can cause serious health problems. It can lead to pelvic inflammatory disease. It can cause life-threatening ectopic pregnancies, and pregnant women can pass the disease to their babies. Gonorrhea can lead to infertility for both men and women, and can make those who have it more likely to get HIV.  

The study about the New Zealand epidemic may change the approach toward developing a vaccine against gonorrhea.

The JAMA article concludes that ultimately, a preventive vaccine could be the only sustainable solution to a fast-changing bug that has proven adept at developing resistance.
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