Genital herpes is a 'forgotten' virus. But that doesn't mean it's gone

Transmission electron microscope image of human herpes virus, HSV. There are two types of genital herpes: HSV-1 and HSV-2.

Genital herpes is very common. There are 42 million new infections each year – that’s one new person infected every second, on average.

While treatments can help with symptoms, there’s no cure. So once someone is infected, they’re infected with the virus for life. In the 15- to 49-year-old age range, 1 in 5 people are living with genital herpes – that’s about 846 million people.

The estimates were published this month in the journal Sexually Transmitted Infections.

“It’s really valuable to have these new estimates so that this virus doesn’t get forgotten forever,” says Dr. Keith Jerome, a professor of virology at Fred Hutchinson Cancer Center. “We’re talking about millions of people living with this infection, and I think it really strengthens the case that it’s time to do more to find new and better treatments and cures.”

NPR spoke with one of the study's authors: Laith Abu-Raddad, a professor of infectious disease epidemiology at Weill Cornell Medicine's Qatar campus, to find out what's causing these huge numbers.

The first question

When talking about his work, Abu-Raddad says one of the first questions he asks is whether the number of cases is increasing or decreasing.

He says the answer isn't that simple. For starters, the methods used to make estimates have changed a lot over the years, as have the data the researchers are using in their analysis.

And then there's the fact that there are two types of herpes simplex virus that cause genital herpes — HSV-1 and HSV-2.

HSV-1 is less common as a source of genital herpes and more commonly appears as oral herpes — mouth sores. HSV-2 is responsible for 90% of genital herpes episodes and has been known to flare up for years.

And their numbers tend to trend in the opposite direction. Also, infection rates vary depending on where you look in the world. But before we get to that, let’s take a look at the basics of the infection.

How you get it

Both HSV-1 and HSV-2 are spread through sexual contact. The HSV-1 virus can also cause oral infections, so it can also be spread through close contact such as shared tableware, slobbery toys shared by children, and even kissing.

Most of the time, these infections go unnoticed. That’s because most people have no symptoms or very few.

However, each year, about 20% of people infected with genital herpes — an unlucky 200 million people — experience at least one outbreak where the virus causes painful genital sores and blisters.

A study in July of this year found that genital herpes costs the world $35 billion, between medical costs and lost economic productivity — for example, the blisters can be so uncomfortable that someone misses work.

“It can be very painful. “There’s a lot of itching, burning, and sometimes large ulcers [sores],” Abu-Raddad says. “But, most of the time, these ulcers are so small that they’re not visible [and not painful], but when we swab people, most of the time we see very active virus.”

HSV-1 …

So now, let’s dive into the details.

Genital herpes, caused by HSV-1, is becoming more common in certain places, such as Japan, Australia, the U.S., and Western Europe. In these places, fewer people are getting oral herpes infections and more people are getting genital herpes.

Why is that?

“What we’re seeing, especially in developed countries, is that fewer and fewer people are getting HSV-1 in childhood because of improved hygiene — people are less likely to share utensils, for example, because family sizes are smaller, so they’re less likely to get it when they play with their siblings,” Abu-Raddad explains. “That’s why more and more people are having oral sex without being infected with HSV-1.”

The bad news is that lack of contact in childhood puts them at higher risk of genital HSV-1 infection.

When it comes to genital herpes from HSV-1, “oral sex is usually the route of transmission,” he says. “A person who has sores in their mouth will have sex with someone who was never infected in childhood, so they’re going to spread the virus to the genital area.”

Abu-Raddad says his team sees a particular increase in genital HSV-1 herpes among college-aged people “because it usually occurs when they start having serious sexual activity in their lives.”

The increasing prevalence of genital herpes from HSV-1 is a decades-old trend that has been documented in various studies. One study called the change “significant,” finding that there were about 252,000 new genital HSV-1 infections in the U.S. in 1970. Fast forward to 2018, and new infections nearly doubled that year to 410,000. The percentage of the total U.S. population increased from 4.5% to 5.4% during that period.

And what about HSV-2?

HSV-2 is the bigger beast of the two because of its ability to reactivate periodically, causing painful new outbreaks. For some people, these outbreaks can appear throughout their lifetime, often due to weakened immune systems.

But there is some encouraging data. In sub-Saharan Africa — where HSV-2 is most common — rates are falling at a “significant” clip, Abu-Raddad says. In the early 1980s, about half the population had HSV-2 but, now, it’s as high as a third of the population.

And HIV plays a role — in reducing the numbers.

This seems counterintuitive because HSV-2 infection actually increases your risk of contracting HIV, doubling or tripling your risk. “These sores basically create a hole for HIV to get in. Also, when these sores occur, there are more immune cells [present in that area] and these immune cells are target cells for HIV,” Abu-Raddad says.

But these rates are largely declining because they are in response to the HIV epidemic that has spread to sub-Saharan Africa.

“After the AIDS epidemic, there were a lot of interventions — so people started using condoms more often, for example,” he says, explaining that condoms reduce the chance of spreading genital herpes. It is these kinds of education and prevention strategies that have helped reduce HSV-2 rates.

There is another sad explanation for this decline: “A lot of people died from AIDS,” Abu-Raddad explains, adding that people who engaged in risky sexual behavior — who were more likely to get and spread HSV-2 — were also more likely to die from AIDS. Sadly, their deaths from AIDS mean that fewer people are alive with HSV-2 and fewer people are spreading it.

What can the unfortunate do?

Unlike high-profile viruses, genital herpes rarely gets the attention — and research funding, Abu-Raddad says.

“People who have genital herpes go out in public and say, ‘Well, I have genital herpes.’ So it’s not visible,” he says. Also, except for rare cases of herpes in newborns, it’s rarely fatal. “And, therefore, we’ve done very little to reduce it.”

The main drug used against genital herpes is acyclovir, one of the first antiviral drugs, developed in the 1950s by Gertrude Allien, who won a Nobel Prize for her work. Dr. “And even today, for herpes, we’re still dealing with a drug that’s mostly 70 years old,” says Jerome. “And in the meantime, you’ve seen a lot of new antiviral drugs for HIV, hepatitis C, hepatitis B, COVID, which is saying something.”

Both men hope that the new statistics on genital herpes — and the story behind them — will help warn people and encourage work on treatments and vaccines.