About STIs

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Number of cases

Reportable STIs

In BC, some sexually transmitted infections (STIs) are reportable to public health. Reportable STIs include chlamydia, gonorrhea, syphilis, and HIV.

Genital chlamydia is the most commonly reported STI in BC and the number of chlamydia infections has continued to rise each year since the late 1990’s. Gonorrhea, the next most commonly reported STI, had 5.8 times fewer cases than chlamydia in 2017. Syphilis is even less common, with 22.5 times fewer the number of cases than chlamydia in 2017.

HIV is less common than syphilis and the number of newly diagnosed HIV infections in BC has been decreasing over time. In 2017, there were 181 new cases of HIV, which is the lowest rate reported in BC.

These numbers are likely an underestimation because many people do not have symptoms and do not get tested, so they are not counted.


HPV is a virus commonly found in human bodies. HPV (human papillomavirus) is a very common STI, but it is not routinely reported. Other studies and statistics have been used to estimate the number of people in BC with HPV.

Over 75% of all sexually active adults in Canada will have at least one HPV infection in their lifetimes. Most people will clear it, so fewer people have HPV at any given time.

There are many strains of HPV, and only some are associated with genital warts or cancer. Of those who have a HPV associated with cancer, only a small number will go on to develop cancer.

In a 2004 study of BC women, between 15 and 69 years of age, 17% had HPV, and 12% had a HPV associated with cancer.

The number of men in BC with HPV is unknown but it is expected to be similar to the number of women. The figure for HPV shows the number of people in BC with HPV at any one time, not the number of new cases.

HPV vaccines  protect against the two most common of these cancer-causing HPV types.

Genital Herpes

Genital herpes is a very common STI, but like HPV, is not routinely reported. Genital herpes can be caused by type 1 or type 2 herpes simplex virus (HSV-1 and HSV-2). Historically, HSV-1 typically caused oral herpes (also called “cold sores”) and HSV-2 caused genital herpes. More recent data show that HSV-1 also causes genital herpes. In BC, up to 40% of genital herpes infections that are tested, are caused by HSV-1.

In some surveys, about 4% of adults say that they have been diagnosed with genital herpes. But other surveys using blood samples, show that about 1 in 5 (17%) adults have HSV-2. This difference shows that many people don’t know they have the herpes simplex virus.

Herpes: 17 out of 100 adults in BC have the virus which most commonly causes genital herpes

This figure shows the number of people in BC with genital herpes at any one time, not the number of new cases.

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chlamydia, gonorrhea, HIV, syphilis, HPV, herpes, case, rate, trends
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