Is Kissing Spreading Gonorrhea?

I got one of the more unusual and interesting messages several months ago: Can you help a friend out with a gonorrhea outbreak in her home? There was no way I was going to say no to that.

When I contacted this person, I found out it was a man and woman, living in a metropolitan area in the Midwest, where they frequently host men and women for sex parties. At a party they held, 10 cis-men and 10 cis-women attended. Women had sex with both men and women, and men only with women. Condoms were used for toys and vaginal and anal sex, but not oral sex.

Here’s where things get even more interesting. The hosts asked everyone to get STI testing within five days after the party, and, more important, to make sure people got more than just their genitals tested. They wanted to also see if people had gonorrhea or chlamydia bacteria in their throat as well.

After the party, five of the men tested positive for gonorrhea in both their throat and urine, as did five of the women. None of them had symptoms.

What Is Gonorrhea and Why Do We Care About It?

Gonorrhea is caused by a bacteria, Neisseria gonorrhoeae, that thrives in warm, moist areas of the body, particularly mucous membranes of the genital area (urethra, cervix), rectum, throat, and eyes. Once it gains entry to the body, it attaches to the epithelial lining. 

In some people, it penetrates tissues, causes inflammation, and produces symptoms. For example, when a man sees me in my clinic and says, “It’s burning when I pee,” I immediately think of gonorrhea, because the bacteria causes inflammation in the urethral passageway in the penis. But not everyone feels symptoms. When gonorrhea attaches to the surfaces of the rectum and the throat, it may just hang out there and not cause any symptoms at all. 

In the genital tract, the longer gonorrhea bacteria linger, the more likely they are to essentially climb the reproductive tract and cause complications. In women, bacteria climb up the reproductive tract and infect the uterus, fallopian tubes and ovaries, leading to pelvic inflammatory disease (PID). PID can result in chronic pelvic pain, ectopic pregnancy, and infertility. In men, gonorrhea can climb up the male genital tract and infect the epididymis.

In both men and women, gonorrhea can escape the genital tract and enter the bloodstream, leading to a systemic condition called disseminated gonococcal infection (DGI). DGI can lead to infected joints, skin lesions, and complete destruction of the heart valves. Probably the most severe case of joint infection I ever saw was a 30-something man during my residency who had an extremely painful knee. You could literally blow air on the knee, and the patient would scream in pain. (Trust me, I only did that when I first examined him and never again!) It turned out to be “septic arthritis” – that is, infection of the joint with gonorrhea bacteria. 

In the throat and rectum, however, gonorrhea has an ability to escape the body’s immune defenses and not trigger symptoms. As I’ll discuss below, we do not know how frequently these infections lead to complications as occur in the genital tract, but we do know they represent a risk to other people.

How Is Gonorrhea Treated?

In the U.S., the recommended treatment in the U.S. is a single intramuscular injection of ceftriaxone, a third-generation cephalosporin antibiotic. While this is highly effective, there is a risk that gonorrhea may eventually develop resistance to all common antibiotics. 

For background, gonorrhea is one of the more worrisome bacterial infections because of its ability to evolve resistance to antibiotic treatment. In the 1930s, the first antibiotic treatment (sulfonamides) were used, but resistance developed within a decade. In the 1940s, penicillin became available and proved highly effective at even low doses. In 10-15 years, however, the dosage of penicillin needed to cure gonorrhea kept increasing, reflecting the evolution of resistance genes within gonorrhea bacteria. By the early 1980s, penicillin became ineffective, and alternative drugs, such as aminoglycosides, macrolides, and tetracycline, were introduced. Unfortunately, they too were not durable, with resistance rapidly emerging through new mutations and acquisition of plasmids. The next class of drugs (quinolones, such as ciprofloxacin) also proved effective for only a short time, and, by 2007, CDC began recommending third-generation cephalosporins—primarily cefixime and ceftriaxone—for treatment. For now, ceftriaxone remains effective, but cefixime and ceftriaxone resistance has been documented in other places (e.g., Japan, Europe) and could spread through the U.S. in the future. That is why drug makers are actively working to develop new antibiotics specifically against gonorrhea. Two of the more promising ones are zoliflodacin and gepotidacin.

A timeline of Gonorrhea antibiotic resistance from https://pmc.ncbi.nlm.nih.gov/articles/PMC4510988/.

How Is Gonorrhea Testing Performed?

When getting tested for these infections, the standard approach is to test a patient’s urine. It’s less invasive and equally as reliable for gonorrhea and chlamydia as swabbing a patient’s genitals.

But these two bacteria can also infect the anus and the throat, the other locations where people, of course, interact sexually with each other. To test these locations, doctors ask you to use a swab that you run around the back of your throat or just inside your anus, then test the swab using PCR. Studies and real-world experience, including in my clinic, show it is safe and accurate for people to collect these specimens themselves.

As of now, CDC and most experts only recommend this more extensive screening—referred to as “three-site testing”—in people who are asymptomatic if they are men who have sex with men (MSM) or transwomen who have sex with men. This is because rates of gonorrhea and chlamydia infections in the throat and anus are high among MSM and transwomen, and it’s assumed that cis-women and straight men do not practice oral and anal sex as frequently as other groups.

How Does Gonorrhea Spread?

So let’s get back to the party. How did 50% of men get infected if they only had sex with women and used condoms when they had penis-in-vagina sex with a woman? And how did women get infected if they used condoms for anal and vaginal sex?

The most likely explanation is that they got infected with their mouths. This matters because I suspect oral transmission is more common than we realize and there is a lot about these infections we do not understand. We don’t understand, for example, why many people have gonorrhea bacteria detectable but no sore throat, fever, or lymph node swelling–the standard symptoms of a throat infection. Of note, almost all studies done on gonorrhea in the throat have focused on MSM, not on straight men and women. The estimate is that up to 17% of MSM have throat gonorrhea infections at any given time. One study done in straight men and women with gonorrhea infection in their genitals found that 39% of them also had it in their throats. 

Why Worry About Gonorrhea Infections in the Throat?

One of the challenges about gonorrhea is that you can be infected, but not have any obvious symptoms of infection.

If you never get tested and just have the infection hanging out there, is it a danger to you? We do know these infections remain in people’s throats, even without symptoms, for four months or longer. And we know that asymptomatic infections in the genitals can lead to infertility and more severe infections. But we do not know if that is also true of gonorrhea infection in the throat.

If you never get tested and just have the infection hanging out there, is it a danger to others? Almost certainly, because there is a risk of transmitting it to other people, as we saw in this party. Unfortunately, we do not know exactly which sex acts led to everyone’s infections. Was it throat-to-throat, throat-to-penis, penis-to-throat, throat-to-vulva, or vulva-to-throat?

Does Kissing Spread Gonorrhea?

We assume most spread is from throat-to-penis, throat-to-anus, and vice versa. But it could also be throat-to-throat, i.e., through kissing. Several studies among MSM in Australia, for example, have found that kissing is one of the strongest risk factors for gonorrhea infection of the throat. I suspect that kissing may have been the main route that infections spread at this part. There are almost certainly far more undiagnosed and untreated gonorrhea throat infections than we realize, because most straight men and women are not being screened routinely for gonorrhea infections in their throats. And kissing may be one way in which it spreads from throat-to-throat in a community, eventually causing genital infections through oral sex.

Why Not Recommend That Everyone Test Throats for Gonorrhea?

So why shouldn’t we test the throats of all people who want STI testing? This is where the priorities of public health, clinical medicine, and insurance clash. For you as an individual, it may be the right decision, especially if you engage in oral sex with new or multiple partners, participate in group sex, have sex with partners who also have other partners, or are part of a community where STI rates are known to be high.

For everyone, public health officials must weigh: how commonly does this occur, how beneficial is early detection and treatment, how much does it cost compared to not doing this and just treating people when they have symptoms, and is limiting funding better used for something else?

CDC already recommends that doctors screen asymptomatic patients for gonorrhea and chlamydia in the genitals using urine testing. Adding two more sites costs more both in dollars and time. Providers often don’t offer it, and patients, especially outside LGBTQ+ communities, don’t know to ask for it.

Is There a Gonorrhea Vaccine?

Until recently, the answer was no. Despite decades of effort, Neisseria gonorrhoeae has evaded every attempt to develop a reliable vaccine, largely because of its complex outer membrane and its ability to change surface proteins to escape immune detection. 

In the United Kingdom, health officials have announced plans to offer the meningococcal B (MenB) vaccine to high-risk populations as a strategy to prevent gonorrhea. Why the meningitis vaccine? Because the bacteria that cause meningococcal disease (Neisseria meningitidis) and gonorrhea (Neisseria gonorrhoeae) are genetically very similar. Observational studies in New Zealand and elsewhere have shown that people vaccinated with MenB vaccines had significantly lower rates of gonorrhea.

Unfortunately, estimates are that the gonorrhea vaccine is only partially protective, reducing the risk of gonorrhea infection 30 to 40 percent. While that sounds low (and is low) from an individual perspective, it could be meaningful at the population level. If there are 30% fewer gonorrhea infections in a community, that could help reduce the use of antibiotics and the risk of further drug resistance emerging, as well as reducing the complications of infections themselves. 

As of now, the MenB vaccine is not recommended in the U.S. specifically for gonorrhea prevention, though the vaccine is now routinely offered to adolescents and young adults to protect against meningitis. 

Should You Get Tested in Your Throat?

Based on everything we know, I believe that we need to start looking for gonorrhea in all the places it persists, regardless of sexual identity or behaviors. My advice is that, if you are sexually active, it’s a good idea to get yourself tested in your throat, genitals, and anus regularly. If your provider hesitates, advocate for yourself. At STI clinics, you can swab your own throat and rectum, and many clinics now offer self-collection kits.