Sex! It’s natural, it’s normal, it’s necessary for the continuation of the human race…and it’s happening a lot less frequently than it used to.
One study comparing the frequency of partnered sexual activity from 2009 to 2018 found a significant decrease among adults and adolescents.
Among adults ages 18 to 49, the amount who reported having no penile-vaginal intercourse within the last year reached 28% in 2018, up from 24% 10 years prior.
A similar trend is happening in teens. For teens aged 14 to 17 in particular, those reporting having had penile-vaginal intercourse within the last year dropped by 10% over the last decade, even before COVID kept us apart.
If you asked teens in the 90s if they’d ever had sex, about half would say they had.
By 2019, that number had dropped to 38%. By 2021, fewer than one-third of teens reported ever having had sex: the largest drop ever recorded.
Whether or not it’s a lasting trend is still to be determined, but a contributing factor could be the increasing fluidity of sexual identity among Gen Z.
75% of teens in a 2021 survey identified as “heterosexual,” down from nearly 90% only a few years before.
So, it’s possible this lack of sexual activity is actually a reflection of government institutions, like the CDC, being behind the times regarding how they define what they are “counting” as sex.
But something else has been dropping in the U.S. in recent years, and that’s the rate of sexually transmitted infections (or STIs).
If you’re wondering why we call them STIs instead of STDs (sexually transmitted diseases), it’s because it’s more accurate: diseases cannot be transmitted, but infections can. And not all infections will cause symptomatic disease or damage, but they can still be passed to others.
According to the CDC, the overall rate of STIs declined by nearly 2% from 2022 to 2023, which is admittedly a small percentage, but 10 years prior, STIs had risen by a whopping 42%
This historical rise could have something to do with the fact that less than half of states require instructions on condom use when talking about sex education. In fact, condom use itself is down–among teens and young adults in particular.
And only three states actually require comprehensive sex education be taught in all schools: California, Oregon, and Washington
Given this information, it shouldn’t shock you to learn that nearly half of all cases of syphilis, chlamydia, and gonorrhea in 2023 were found among young adults aged 15-24.
Here’s a quick refresh on the basics of STIs, starting with the classic trifecta of syphilis, gonorrhea, and chlamydia.
It’s a bacterial infection, typically spread by sexual contact, and the diagnosis of syphilis is broken down into four stages.
Primary syphilis develops three to six weeks after exposure and typically presents as a painless ulcer at the site of infection, but it can also be characterized by several painful lesions.
Four to six weeks after the development of a primary sore, secondary syphilis can develop if primary syphilis goes untreated. This stage is marked by a skin rash, generally found on the palms of the hands or soles of the feet, sores, fever, and general unwell feeling.
The symptoms for both primary and secondary syphilis typically resolve on their own, leading to the latent phase of syphilis, which has no symptoms but can continue to damage organs.
Continue to leave syphilis untreated, and some (though not all) people will develop tertiary syphilis about 10-30 years after the initial infection. This stage is marked by damage to several organ systems including the heart, blood vessels, brain, and nervous system.
Thankfully, this timeless infection still has an equally timeless cure: cases of primary and secondary syphilis can still be effectively treated with a single shot of penicillin, and later stage syphilis requires multiple shots.
In 2023, though we still had over 200,000 cases of syphilis diagnosed in the U.S., it represented only a 1% increase, which was much lower than the double-digit increases we had been seeing each year prior.
Plus, cases of primary and secondary syphilis (which are the most infectious stages) dropped by 10%, which was the first substantial decrease in two decades.
Unfortunately, one area where syphilis is on the rise is in cases of congenital syphilis, which is when syphilis goes untreated in a pregnant person, who then passes the infection to the baby.
These cases of syphilis have seen a 10-fold increase in the last decade, and the CDC estimates nearly 90% of those could have been prevented, indicating a lack of access to proper prenatal care.
The second most common STI out of the three is gonorrhea.
Also a bacterial infection, many people who have gonorrhea experience no symptoms, and even when someone does experience symptoms, they can often be mild and mistaken for other ailments.
Symptoms include painful urination, unusual discharge, and bleeding from the site of infection.
Gonorrhea infection without symptoms can still cause long term damage to reproductive organs in both men and women, increasing the risk of infertility, complications during pregnancy, and contracting HIV.
Just like syphilis, most cases of uncomplicated gonorrhea can be treated with a single dose of an antibiotic (ceftriaxone), but unlike syphilis, antibiotic resistance is starting to become an issue.
But the good news is that gonorrhea rates are reducing the fastest of any STI. Rates declined by 7% from 2022 to 2023, with a much more pronounced drop of 14% among women.
And last, but certainly not least, is chlamydia.
There were over a million and a half cases in 2023, making it the most commonly diagnosed STI.
It is very similar to gonorrhea in that not everyone has symptoms, and that, left untreated, it can seriously impact your reproductive health.
Currently, the rates of chlamydia seem to be stable, rising less than 1% in 2023.
What is causing this sudden decline in STIs?
A few factors are likely at play. The fact that fewer people are having sex likely has something to do with it. Another factor is the use of the antibiotic doxycycline as post-exposure prophylaxis.
Recent studies showed that, for high-risk groups (such as men who have sex with men and trans women) with a recent history of STIs, taking the antibiotic within 72 hours of unprotected sex dramatically reduced the incidence of syphilis, chlamydia, and gonorrhea.
Additionally, the FDA has approved home tests for syphilis, chlamydia, and gonorrhea, which can remove barriers to accessing care for some people.
Of course, more must be done to increase access and address disparities. Despite only making up about 13% of the total population, Black Americans accounted for nearly one-third of all newly diagnosed STIs.
Another virus transmitted through sexual contact is human papillomavirus.
Human papillomavirus (HPV) is an extremely common viral infection, with over 100 different strains that can cause genital warts and certain types of cancer.
It’s estimated that nearly everyone will get an HPV infection at some point in their life.
All warts are caused by an infection with HPV, but the type of wart you get depends on the strain of HPV you’re infected with—and the strains of HPV that cause warts do not cause cancer.
9 out of 10 infections will resolve on their own, but for the 10% that don’t, they can go on to cause cancer of the cervix, vagina, penis, anus, or throat.
Thank goodness for that safe and highly effective HPV vaccine!
Kids are eligible for the vaccine starting at age 9, but two doses are recommended between the ages of 11 and 12. This is because it’s the most effective when given before sexual activity begins.
In teen girls who were vaccinated, infections with the types of HPV that cause genital warts or cancer dropped by 88%
In Scotland, where HPV vaccinations were rolled out in 2008, there have been zero cases of cervical cancer in vaccinated women born between 1988 and 1996 who were vaccinated as 12 to 13 year olds.
Herpes simplex viruses can cause oral and genital herpes,
Many people don’t realize that they’re probably carriers.
There are two types of herpes simplex viruses: HSV-1 and HSV-2
50-80% of American adults have HSV-1, also known as oral herpes, more commonly recognized as cold sores.
Many people are infected with HSV-1 in childhood because it can spread through saliva. People can also get HSV-1 infections on their genitals from receiving oral sex from an infected person.
HSV-2 is the virus commonly associated with genital herpes, which affects an estimated 1 in 6 adults aged 14 to 49.
While genital herpes can cause painful sores, a lot of cases remain asymptomatic and go undetected.
Many people who are carriers of HSV don’t know they have it, because it’s not part of the routine panel of STI tests.
HSV can transmit to others without symptoms, but only from the area where the infection occurred.
Because the blood test for HSV doesn't tell you where you were infected, only that you were exposed, it’s mostly used to confirm the cause of genital sores or blisters when someone has symptoms.
Although HSV is currently a lifelong infection, it can be controlled with viral suppression, either during episodes of outbreaks or chronically for people who have frequent outbreaks or partners who are HSV negative.
The use of antivirals, barriers like condoms and dental dams, and abstinence when an outbreak feels imminent, can significantly reduce the risk of passing the virus on, though not eliminate it entirely.
The lack of understanding about just how common herpes is directly relates to the stigma surrounding the infection. This stigma can not only prevent people from seeking care or information about potential infections, but also prevent people who have known herpes infections from appropriately talking to their partners about ways to prevent transmission.
