The infection
Genital herpes is caused by herpes simplex virus type 1 or type 2. Type 2 was classically genital and type 1 oral, but that has changed: in several countries type 1, passed on during oral sex, is now the leading cause of genital herpes in young adults. Once acquired, the virus stays for life in the nerve ganglia and can reactivate — though many infected people never have a recognised outbreak.
Key facts
| Organism | Herpes simplex virus type 1 or 2 |
|---|---|
| Incubation | 2 to 12 days for a symptomatic first episode |
| Unrecognised infection | The majority: most carriers do not know |
| Test | PCR on a swab from a lesion; serology is of little screening value |
| Curable | No: infection is permanent, but treatment controls it |
| Shedding without lesions | Common, and the main route of transmission |
| Pregnancy | Serious neonatal risk, above all with late first infection |
How it is transmitted
The virus passes through direct contact with a lesion, but above all during asymptomatic shedding, when the virus is present on the mucosa with nothing to see. That is why most transmission occurs outside outbreaks, and why appearance is never a reliable guide. A cold sore can transmit genital herpes during oral sex.
Symptoms
The first episode, when symptomatic, is the most severe: clusters of painful blisters that ulcerate, burning, fever, swollen glands, difficulty passing urine. It lasts one to three weeks. Recurrences are shorter and milder, often preceded by tingling or burning, and generally become less frequent over the years. In many people the infection never announces itself recognisably at all.
Testing
Diagnosis is by PCR on a swab from a lesion, ideally taken at the very start of an outbreak. Serology detects antibodies but does not say where the infection is, and is not recommended as routine screening: a positive result in someone without symptoms generates more anxiety than useful information. It retains a role in specific situations, particularly around pregnancy.
Treatment
Antivirals — aciclovir or valaciclovir — do not eliminate the virus but shorten outbreaks and reduce their severity. They can be taken episodically at the first sign, or continuously where recurrences are frequent or to reduce transmission to an uninfected partner. Continuous suppressive treatment is well tolerated and substantially reduces outbreak frequency.
If left untreated
In healthy adults genital herpes is mainly a physical and psychological burden, sometimes a heavy one. Serious complications concern newborns: neonatal herpes is rare but severe, and the risk is highest when the mother acquires a first infection late in pregnancy. Herpes also increases the risk of acquiring HIV, the ulcers providing a point of entry.
Prevention
- Condoms roughly halve the risk: they do not cover every area where the virus may be present.
- Avoid sex during an outbreak, from the first tingling until the skin has fully healed.
- Continuous antiviral treatment markedly reduces transmission to an uninfected partner.
- Tell your midwife or doctor in early pregnancy: monitoring and delivery planning depend on it.
After a diagnosis
- Tell your partner: it is the basis of effective prevention, and the infection is far too common to warrant drama.
- Identify your own triggers: tiredness, stress, periods, sun exposure, fever.
- Having a prescription in advance lets you start at the first sign, which changes the length of an outbreak considerably.
- Declare the infection at the first antenatal appointment if you are pregnant.
Worth remembering
No carrier can guarantee they will not transmit, even with no visible lesion. That is why telling a partner, rather than watching for symptoms, is the real preventive measure.
A little history
The word comes from the Greek herpein, "to creep", and is already found in Hippocrates for lesions that spread across the skin. Genital herpes as a distinct entity was described in 1736 by the French physician Jean Astruc in his treatise on venereal diseases. In 1873 Émile Vidal proved the disease was contagious by inoculating it from one person to another; in 1919 Löwenstein transmitted the virus to the rabbit cornea, demonstrating that it was indeed a virus.
It took until the 1960s to distinguish two viruses: HSV-1, mostly oral, and HSV-2, mostly genital, a separation established by Karl Schneweis in 1962 and confirmed by André Nahmias and Walter Dowdle in 1968. Aciclovir, discovered in 1974 in Gertrude Elion's team at Burroughs Wellcome and marketed in the early 1980s, was the first truly selective antiviral: it earned Elion the Nobel Prize in Medicine in 1988. Valaciclovir and famciclovir are its descendants.
The early 1980s were also a time of moral panic in the United States: in August 1982 Time magazine put herpes on its cover as "today's scarlet letter". AIDS, which appeared the same year, soon pushed that fear into the background — but the shame attached to an extremely common infection dates from then. No vaccine exists yet, despite repeated trials since the 1990s.
How this differs between countries
This is the infection on this list where countries differ least: nobody screens for it, and the treatment is the same everywhere.
- No screening anywhere. Serological screening of people without symptoms is not recommended in any country: it generates anxiety without demonstrated benefit.
- Reimbursement of antivirals. The main difference is financial: treatment of outbreaks is covered in many countries, continuous suppressive treatment far less often.
- Availability. Aciclovir is on the World Health Organization's essential medicines list and is widely available, including as an inexpensive generic.
- Delivery planning. Guidance on caesarean section after a late first infection varies slightly, but the principle is the same everywhere.
- Neonatal herpes. Reported more often in countries with organised surveillance, which reflects detection rather than a real difference in incidence.