A mass vaccination campaign against meningitis in New Zealand had an unexpected side-effect — it helped protect people against gonorrhea, too. The meningitis vaccine lowered the risk of gonorrhea by more than 30 percent, researchers reported in Tuesday’s issue of the Lancet. People receive a free meningitis vaccine at the AIDS Healthcare Foundation pharmacy in Hollywood in 2013. Kevork Djansezian / Getty Images file It’s surprising news, even though the bacteria that cause gonorrhea and the bacteria that cause meningitis are related. That’s because infection with gonorrhea doesn’t make people immune to becoming infected again later. And most meningitis vaccines don’t seem to have infected gonorrhea rates at all. And the findings show yet another benefit of vaccinating teenagers — who get recommended vaccines at a much lower rate than younger children do. “To our knowledge, ours is the first study to show an association between a vaccine and a reduction in the risk of gonorrhea,” Dr. Helen Petousis-Harris of the University of Auckland in New Zealand and colleagues wrote in their report in the Lancet. There had been some evidence that gonorrhea rates went down after use of a vaccine against one strain of meningitis, called meningitis B. This was a particularly tough strain to develop a vaccine against, and other meningitis vaccines don’t protect against meningitis B. The vaccine was used in a mass campaign of a million people in 2004 to 2006. The researchers looked for visitors to sexually transmitted disease clinics to see if having been vaccinated made a difference. It did. They found 14,000 people for their study, including 1,200 people who had gonorrhea and more than 12,000 who had chlamydia, another STD. The meningitis vaccine wouldn’t be expected to protect against gonorrhea and it did not. But people who got the meningitis B vaccine were about 30 percent less likely to have gonorrhea than those who did not, the team reported. “There is a disconnect between teenagers' belief that their health is important and their actions.” “MeNZB was developed to control an epidemic and is no longer available,” the researchers said. But a new vaccine, called Bexsero, has