Cold Sores and Oral Sex: What You Actually Need to Know About Herpes Transmission

BeWellAdmin
4 days ago
6 min read

Here is something that surprises students: cold sores can cause genital herpes. Healthcare providers at Queen's have noticed that sometimes students are surprised to learn that you can contract herpes from someone who has no visible sores.

Cold sores are so common that they are easy to dismiss, but they impact sexual health. The virus behind most cold sores (HSV-1) spreads through skin-to-skin contact which means can be transmitted during oral sex, vaginal and anal sex.

If you have ever thought cold sores were "just cold sores" or assumed herpes only spreads when someone has visible sores, you are not alone. These are common misconceptions. But understanding how herpes works can help you make informed decisions about your sexual health and have better conversations with your partners.

This is not meant to scare you or make you feel anxious about intimacy. Herpes is a common sexually transmitted infection (STI) but is very manageable. Knowing the facts empowers you to protect yourself and your partners without unnecessary fear.

What Are Cold Sores, Really?

Cold sores, those small blisters that appear on or around the lips, are caused by the herpes simplex virus type 1 (HSV-1). Most people acquire HSV-1 during childhood, often from a kiss from a family member. By adulthood, most Canadians carry the virus, whether they have ever had a visible cold sore or not.

There's also herpes simplex virus type 2 (HSV-2), which traditionally causes genital herpes. But here's the important part: either virus can infect either location. HSV-1 from someone's mouth can be transmitted to a partner's genitals during oral sex, causing genital herpes. This is becoming increasingly common, especially among young adults.

Once you have herpes of either type, in either location, it stays in your body permanently. The virus lives in nerve cells and can remain dormant for months or years. Some people have frequent outbreaks; others rarely or never have visible symptoms. This variability is part of why herpes spreads so easily.

The Surprise Factor: Asymptomatic Shedding

This is the piece most people do not know: herpes can spread even when there are no visible sores.

The virus periodically "sheds" from the skin or mucous membranes without causing any symptoms, no tingling, no blisters, nothing visible. The person shedding the virus has no way of knowing it is happening. According to the Public Health Agency of Canada (PHAC), there are several days each year when this occurs, and the World Health Organization confirms that HSV-1 can be transmitted even when the mouth looks completely normal.

Planned Parenthood reports that only 10–15% of people with herpes have noticeable symptoms, and most new infections occur during these asymptomatic periods. This means waiting until you see a cold sore to take precautions is not an effective prevention strategy, the risk exists even when everything looks fine.

How Common Is This, Actually?

More common than you might think. The 2009–2011 Canadian Health Measures Survey found that about 13.6% of Canadians aged 14–59 have antibodies to HSV-2 (genital herpes). That's roughly one in seven people. HSV-1 is even more prevalent; the majority of adults carry it.

Regional studies in Nova Scotia and New Brunswick found that more than half of genital herpes infections were caused by HSV-1, not HSV-2. This shift reflects changing sexual practices and highlights that oral sex is a significant transmission route for genital herpes, particularly among younger people.

Recent research found genital herpes diagnoses occurring in about 5–6 per 1,000 students, and that's just the cases that were diagnosed and reported. Many infections go unnoticed because symptoms are mild or absent.

The point is not to alarm you. It's to help you understand that herpes is a normal part of human health, not a rare or shameful condition. Knowing your risk and taking practical precautions is simply smart self-care.

Protection That Actually Works

The good news: there are effective ways to reduce transmission risk. The most important tools are barrier methods: condoms and dental dams, used consistently during oral sex.

Dental Dams for Oral-Vaginal and Oral-Anal Sex

Dental dams are thin sheets of latex or polyurethane that create a barrier between the mouth and the vulva or anus. They block the exchange of bodily fluids and reduce skin-to-skin contact where the virus might be present. Canada's Public Health Agency recommends dental dams for oral-vaginal and oral-anal sex.

If you do not have a dental dam, you can make one by cutting the tip and base off a condom and slicing it lengthwise to create a flat sheet. It's not as convenient as a purpose-made dam, but it works in a pinch.

Condoms for oral-penile sex

For oral sex on a penis, condoms provide effective protection. They cover the mucous membranes most likely to transmit or receive the virus. Flavoured condoms are designed specifically for oral sex if taste is a concern.

Tips for Effective Barrier Use

Use a new barrier for each sexual act; do not reuse or flip them over. Check the expiry date and inspect for tears before use. Use water-based or silicone-based lubricants; oil-based products can weaken latex. Avoid spermicides containing nonoxynol-9, which can irritate tissues and potentially increase infection risk.

Barriers do not eliminate risk; herpes can be present on areas not covered, but they significantly reduce transmission. Combining barrier use with other precautions offers the best protection.

Avoiding Contact During Outbreaks

While herpes can spread without visible symptoms, the risk is highest during active outbreaks. If you or a partner has a cold sore or feels the tingling, itching, or burning that often precedes one, avoid oral contact until the skin has completely healed and looks normal.

This means no kissing and no oral sex until the outbreak has fully resolved. It also means not sharing items like drinks, lip balm, or utensils during an outbreak, since HSV-1 can be transmitted through saliva.

Having the Conversation

Talking about cold sores and sexual health might feel awkward, but it's one of the most effective ways to protect yourself and your partners. Honest communication builds trust and allows you to make decisions together.

A simple approach might sound like: "Hey, before we go further, I wanted to mention that I sometimes get cold sores. They're caused by a virus, which can spread through oral sex even when there's no visible sore. I wanted you to know so we can decide together how to stay safe."

If you're on the receiving end of this conversation, try to respond without judgment. Remember that the person is being responsible and honest, qualities you want in a partner. Together, you can discuss using barriers, avoiding contact during outbreaks, and what feels comfortable for both of you.

It's also okay to ask partners about their history with cold sores before engaging in oral sex. This isn't accusatory; it's taking care of each other.

Testing, Diagnosis, and Treatment

Testing can be important, especially if you have symptoms, a partner with herpes, or a recent exposure. If you have a sore or blister, the most useful approach is to get it assessed promptly so a clinician can do a swab/PCR test from the lesion (this is the most direct way to confirm HSV and type it).

If you do not have symptoms, blood tests can still be helpful in specific situations (for example, when a partner has herpes and you are trying to clarify risk), but they are not automatically included in routine STI panels because results can be hard to interpret and can sometimes cause harm through false positives or confusion about where HSV is located (oral vs genital).

There is no cure for herpes, but antiviral medications can reduce the severity and duration of outbreaks. For people with frequent recurrences, daily suppressive therapy significantly reduces viral shedding and lowers the chance of transmitting the virus to partners. If you are diagnosed with herpes and experiencing frequent outbreaks, talk to a healthcare provider about whether suppressive therapy might be right for you.

Getting Tested at Queen's

If you are concerned about herpes or other sexually transmitted infections, Queen's offers STI quick-test clinics available by appointment. These clinics provide confidential testing and can answer questions about your sexual health. You can also visit the Student Wellness Services for guidance on testing, prevention, and treatment options.

Getting tested regularly, especially if you have new partners, is a responsible part of sexual health, alongside using barriers and communicating openly. Student Wellness’s sexual health resources can help you find additional support and information.

Reducing Stigma, Increasing Safety

Herpes carries more stigma than it medically deserves. It's extremely common, usually mild, and does not define anyone's worth or character. The shame surrounding herpes often prevents people from disclosing their status or seeking treatment, which paradoxically, increases transmission.

If a partner discloses herpes to you, they're being honest and trustworthy. Approaching this topic with compassion rather than fear helps everyone stay healthier and maintains the trust that makes intimate relationships work.

The Bottom Line

Cold sores are herpes. They can spread to a partner's genitals during oral sex, even when no sores is visible. This is how many students at Queen's and across Canada are contracting genital herpes without realizing the risk.

Protecting yourself doesn't require avoiding intimacy. It means using condoms and dental dams during oral sex, avoiding oral contact during outbreaks, and talking with partners about cold sore history before things get heated. These are simple, practical steps that significantly reduce risk while allowing you to enjoy healthy relationships.

If you have questions or want to get tested, book an appointment at a Queen's STI quick-test clinic or visit Student Wellness Services. Knowledge and communication are your best tools for staying healthy.