There can be epidemiological bad consequences from kissing, but you don’t have to be squeamish about it if you’re careful and exercise good oral hygiene. The romantic consequences are another matter—not considered here.
The eagerly-awaited revival of the London West End production Angels in America on Broadway is merely the most expensive stage and screen reminder of the terrifying early days of what was to become the AIDS epidemic. Having lived in San Francisco for its first two decades, it all comes back with terrible force.
What stand out for me are the details that would look quaint in light of our current understanding of HIV illness. When transmission routes were still a matter of speculation, there was the very real—pressing, if you will—question of whether a smooch of whatever duration was potentially a kiss of death. In a kissy country like the U.S., even a peck on the cheek was briefly an act of courage.
Having spent the next two decades in Southeast Asia, where kissing isn’t even a thing for the sector of the population that hasn’t been Westernized, I’ve noticed how my host culture's aversion to kissing has infected me in a new way. Now when I see a passionate kiss of what could be called the full-throated variety, on TV or at the movies, I notice my own initial “ew” reaction.
I suspect that, like the aged trumpeter, I’ve lost my lip. When, recently, a Twitter link led me to a performance of the grisly final scene of Richard Strauss’ Salome, where the iconic “bad girl” of opera kisses the severed head of John the Baptist presented to her on a silver platter, I nearly lost my mind.
Where, I’ve wondered since, are we with kissing as viewed through the eyes of infectious diseases and public health?
So do we have to kiss kissing goodbye?
In short, No. But the curtain may be closing on the time when “Give me a big sloppy kiss!” was the height of invitation.
The fact remains that any number of infectious diseases can be transmitted by any buss stronger than a peck on the lips. You’re in no danger of contracting arthritis from granny’s dry-lipped greeting. But neither is the lip-lock a free-range activity.
CNN cites a 2014 study that in the average ten-second kiss (you might well ask, What ten-second kiss is average?), 80 million bacteria are transferred, along with viruses that are worth giving a thought. The study has the romance-killing title, “Shaping the oral macrobiota through intimate kissing,” but it’s reported in lay language and worth a read.
Here’s from its “Results” section (verbatim): “An intimate kiss did not lead to a significant additional increase of the average similarity of the oral microbiota between partners. However, clear correlations were observed between the similarity indices of the salivary microbiota of couples and self-reported kiss frequencies, and the reported time passed after the latest kiss.”
Its “Conclusion” section is a bit rougher sledding, language-wise, but here’s the first sentence: “This study indicates that a shared salivary microbiota requires a frequent and recent bacterial exchange and is therefore most pronounced in couples with relatively high intimate kiss frequencies.” In all that language, the key word is “couples.”
As anyone who’s read John Updike’s famous novel of that title knows, not all kissing behavior takes place among what could be called recognized couples.
So WHAT viruses?
Not many surprises here. Viruses easily transmissible through kissing include:
One at a time
1) While common respiratory viruses can easily be spread through intimate kissing, medical specialists are quick to add that you’re more likely to get any contagion well before kissing, or through another route. The other routes are being within 3-6 feet of someone sneezing or coughing or touching a surface contaminated with a sick person’s mucous.
2) Thought of as a young people’s disease because people most at risk are in their mid-teens to their early 30s—ages when people are apt to be in close contact with others—mononucleosis is caused by the Epstein-Barr virus. It is not the chronic version of that disease, but neither is there any treatment for it except rest and time. Its telltale symptom is extreme fatigue, but other symptoms include fever, sore throat, muscle soreness, and swollen lymph glands.
3) The U.S. Centers for Disease Control reports that half of Americans carry the herpes simplex virus. Its most frequent—and, relatively speaking, mild—symptoms are cold sores and so-called “fever blisters.” The lightest, briefest of kisses is enough for virus transfer, which makes children particularly vulnerable to parents’ and each others' affection. The virus is often “shedding” before symptoms are visible.
4) Cytomegalovirus is another herpes virus, also common in adult populations, most of whom have developed antibodies to it. It’s a particular risk for people with compromised immune systems, who usually react to it with fever, muscle soreness, and fatigue. But severe cases can lead to pneumonia, encephalitis, and even seizures. It is transmitted through saliva, blood, urine, semen, and breast milk.
5) Like colds and other respiratory diseases, infections caused by Group A streptococcus are as likely spread through other forms of contact, though kissing is a sure route of infection. It usual consequences, such as strep throat, are easily treated with antibiotics, But untreated, it can lead to pneumonia.
6) HPV-related warts could be passed only through sores in the mouth of on the lips, and then with considerable contact.
7) If any of these is a surprise, it’s like to be the transmissibility of tooth decay and gingivitis (“gum disease”). In short, your own oral hygiene, however scrupulous, will only get you so far. The London Doctors Clinic explains is this way (verbatim):
“When kissing, you don’t just share saliva – you also share the flora of bacteria, viruses and mucus that live in your mouth!
“Gum disease itself cannot be spread by kissing, but the ‘bad’ bacteria that cause it definitely can be - this is more likely to happen when your immune system of your mouth is compromised. These germs build up and form plaque, which can cause cavities or gum disease (gingivitis) when it builds up under your gum line.
“The spread of 'bad bacteria’ is more likely to occur if the natural immune system for your mouth is compromised. Your best bet at preventing this is to maintain good oral hygiene, by brushing your teeth twice a day and flossing before bed. This will prevent the bacteria from being able to grow in your mouth.”
8) Polio is a highly infectious viral disease spread through oral contact or contaminated food or water. After it enters the intestine it leads to nerve damage and paralysis. It was once considered eradicated in the U.S. and most of the developed world. But the fact that still exists, and at epidemic levels, in some, mostly “third-world” cultures, it can no nlonger be considered a negligible concern given increasingly common family international travel, and even Western health-care systems are currently being degraded by government cutbacks.
What about STDs?
The London Doctors Clinic again:
“Although most commonly transmitted by sex, syphilis can also be spread by kissing. This is because syphilis can cause round, open and infectious sores in the mouth. Syphilis can be treated by doctor-prescribed antibiotics.
“Other STIs such as HIV, chlamydia and gonorrhoea are less likely to be spread by kissing (unless one of you have a cut or sore in your mouth). If you're worried about sexual health, find out more information here.”
It absolutely warrants saying that under anything like normal circumstances, HIV and most STDs cannot be transmitted through kissing alone. The exception is infection through a cut or an open sore in the oral region through which any virus could be transmitted.
Are we done yet?
Yes. Except to add that it’s London Doctors Clinic to the rescue yet again. It concludes its article—very much worth a read—by listing the health benefits (their word) from passionate (their word) kissing. They include:
“As well as this, most kisses won’t cause disease - realistically, your chance of catching one of the above-mentioned nasties is pretty small!”
As I conclude, in the background Salome is puckering up at some pretty excited decibels. Good to remember that she’s the definition of an extreme cases, and her result was immediate death at the hands of her father’s soldiers.
Generally speaking, if you want to remain positive (in the attitudinal, not laboratory sense) about smooching, a good place to avoid is the opera house.