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In the news! Commonly asked questions about STIs

The British Columbia Centre for Disease Control (BCCDC) is often asked to comment on infectious diseases in the province. Questions about sexually transmitted infections (STIs) are common, and often get attention from both the public and the media. Using the most recent epidemiological data from BC, we have provided answers to the seven most common STI questions recently asked in the media.

1. Are STIs actually on the rise? Which ones?

Yes, STIs are on the rise. With the exception of HIV, most other sexually transmitted infections are increasing in BC.

Chlamydia is the most common STI in BC, and continues to increase: In 2017, there were 15,646 cases of chlamydia reported in BC (325 cases per 100,000 people), including cases of both genital and extra-genital chlamydia. This is 3% higher than in 2016.  Young adults aged 20-29 have the highest rates of chlamydia. Females continue to have approximately 1.5 times the diagnosis rate compared to males (Figure 1).

Graph of trends in Chlamydia in BC from 2005 to 2017

Gonorrhea has increased more dramatically lately:  In 2017, there were 3,281 cases of gonorrhea (68 cases per 100,000 people), including cases of both genital and extra-genital gonorrhea. Gonorrhea has been increasing since 2005, including a 70% increase in cases from 2014 to 2015. Like chlamydia, young adults aged 20-29 have the highest rates of gonorrhea. However, males are 2-3 times more likely to be diagnosed with gonorrhea than females (Figure 2).  Possible reasons include: (A) males are more likely than females to have symptoms that compel them to get tested [1] (B) higher rates of gonorrhea among gay, bisexual, and other men who have sex with men.

Graph of trends in Gonorrhea in BC from 2005 to 2017

Infectious syphilis has surged since 2010, but may be stabilizing: In 2017, there were 685 cases of infectious syphilis reported (10.8 cases per 100,000 people), which is 10% lower than in 2016 (Figure 3).  Males between the ages of 30-59 continue to have the highest rates of infectious syphilis and gay, bisexual, and other men who have sex with men are disproportionately affected by infectious syphilis.

Graph of trends in Infectious Syphilis in BC from 2005 to 2017

The number of HIV cases in BC continues to decrease: From 2005 to 2017, the number of new HIV diagnoses in BC declined by 50%. In 2017, the number of new HIV diagnoses was the lowest reported in BC since HIV became reportable (Figure 4). Gay, bisexual, and other men who have sex with men are still disproportionately affected by HIV, and the risk of HIV is highest among those aged 25-39 years. The reduction in HIV is largely due to improved effectiveness of and access to antiretroviral drugs, as well as improvements in harm reduction (e.g. needle distribution programs) for people who inject drugs.

Graph of trends in HIV in BC from 2005 to 2017

STI trends in Canada are available up to the end of 2016 and they show a similar pattern to what we observe in BC.[2] This is with the exception of HIV, where national rates increased slightly compared to the previous year.[3]

2. Why are STI rates increasing in BC and in Canada?

There is no single explanation for the increased rates of STIs observed over the past decade. Multiple factors have contributed to this trend, including: 

  1. Increased awareness and testing: Increased testing, especially among young adults, has led to increased detection of STIs. Because many STIs have no symptoms, regular testing for STIs is important. Routine offering of STI testing by health care providers has also contributed to this trend. For example, health care providers routinely offer STI testing during visits for pap testing, or birth control counselling.
  2. Improvements in diagnostic tests:  Diagnostic tests for STIs are more sensitive, quicker and more acceptable to patients now. For example, a majority of chlamydia and gonorrhea infections in BC are diagnosed using Nucleic Acid Amplification Tests (NAAT), which are more sensitive at detecting infections compared to bacterial cultures. In addition, NAAT can detect infection using urine samples, which is much less invasive for patients than urethral or cervical swabs. The combination of these factors has led to more diagnoses of STIs.
  3. Changes in sexual practices: There is some evidence that suggests condom use is decreasing, including among gay, bisexual, and other men who have sex with men; this may be due to HIV treatment optimism among this group (discussed below).[4,5,6]  The use of online dating sites has also been suggested as a potential reason for increasing STIs, but the these associations are difficult to measure.[7]

3. Are dating sites & hookup apps contributing to the increase in STIs?

The impact of online dating on STIs is difficult to measure. Online dating sites and hookup apps can promote sexual practices that increase the chance of STIs, such as multiple sexual partners, concurrent sex partners, and sex with anonymous partners.[8] However, some studies indicate that individuals who engage in higher-risk sexual behaviours online also engage in higher-risk behaviours offline. A study of 30,000 men who participated in the Australian Gay Community Periodic Surveys (2010-2014) found that men who had the highest rates of STIs reported using multiple methods to meet partners (online websites, hook-up apps, sex venues etc.), compared to those who used exclusively online or offline methods.[9] 

Alternatively, this technology can also be used to reduce the spread of STIs, for example, by supporting the notification of sex partners. Some hook-up apps are already exploring ways to allow people who test positive for an STI to notify their partners using the app.[10]

4. Are STI rates increasing in seniors? Why?

Although the rates of STIs among older adults are lower than in the general population, they have been increasing. The most recent estimates for people age 60 and older show that rates of gonorrhea, chlamydia and infectious syphilis have more than doubled from 2010 to 2016 in BC:

  • Rate of chlamydia increased from 5.7 per 100,000 to 10.7 per 100,000
  • Rate of gonorrhea increased from 3.1 per 100,000 to 6.3 per 100,000
  • The rate of infectious syphilis increased from 1.8 per 100,000 to 5.0 per 100,000

Promoting healthy sexuality throughout life is important, particularly as individuals live longer, healthier lives. Unfortunately, messages around STI prevention and testing rarely target older individuals. This results in misconceptions about the chance of getting or passing STIs, outdated knowledge about safe sexual practices, and a lack of awareness of the importance of testing, all of which may be contributing to increased STI rates in this population.[11]

5. What can people do to protect themselves?

Get tested: It is possible to have an STI and not know it, meaning it can be passed to others or lead to serious health problems if untreated. It’s recommended to get tested whenever you start a new relationship or see a new sex partner. People living in or near Vancouver, Kamloops, Nelson, Victoria or Duncan, can even get tested without having to see a clinician first. GetCheckedOnline is an online service from the BCCDC that offers easy, confidential testing for STIs and HIV.

Talk with partners: It can be easier in the heat of the moment when you and your partners have talked beforehand about sexual health and STI testing. There are lots of ways to start this conversation.

Use protection: Use a new condom every time you have vaginal, anal or oral sex.

6. Is there antibiotic resistant gonorrhea in BC?

The most recent guidelines in BC recommend third-generation cephalosporins (i.e. ceftriaxone or cefixime) co-administered with azithromycin for the treatment of gonorrhea.

The trends in antibiotic resistance in BC have varied over time. From 2007 to 2010, there was an increasing trend in gonorrhea with reduced susceptibility to cefixime, ceftriaxone and azithromycin; the trend reversed from 2011 to 2016 (susceptibility means more of the drug is needed to stop the bacteria). This decline may be due to changes in the Canadian and provincial gonorrhea treatment guidelines to more effective regimens (i.e., increased cefixime dosage or improved medication adherence due to single dosage).[12] 

In BC, we did not find any fully resistant strains of gonorrhea and no treatment failures were reported between 2007 and 2016. However, treatment continues to be challenged by antibiotic resistance. Most recently, there was a slight increase in the proportion of gonorrhea with reduced susceptibility to cefixime. This is being closely monitored to inform future gonorrhea treatment recommendations.

The continued threat of emerging resistance reinforces the need for STI prevention and control measures such as increased testing for gonorrhea, partner testing and treatment of gonorrhea, and tests of cure, as well as the need for antibiotic stewardship to ensure effective treatments for bacterial infections.

7. Does “HIV treatment optimism” and prevention tools like PrEP lead to higher rates of STIs because people are more willing to engage in riskier sexual activities?

There have been remarkable advances in the prevention and treatment of HIV over the past two decades. BC now publically funds antiretroviral therapy for people living with HIV as well as pre- (PEP) and post-exposure prophylaxis (PrEP) to prevent HIV. As a result, the number of new HIV diagnoses in BC has been decreasing and people with HIV are living longer.

While these advancements allow people to live healthier lives, they may also mean that people are less concerned about HIV (also known as HIV treatment optimism). Some studies have found that treatment optimism results in higher risk sexual behaviours (e.g. condomless sex).[13,14]  However a recent study out of Vancouver did not demonstrate this.[15]  Similarly, there has been conflicting evidence about whether starting on HIV PrEP results in an increase in STIs, though a recent Montreal study did find this association.[16]  

Overall, bacterial STIs, such as chlamydia, gonorrhea, and syphilis, are curable and are associated with fewer complications than HIV. It is reasonable that HIV prevention and treatment is given priority. However, as we move into the era of improved HIV prevention, new strategies are needed to reduce the burden of STIs in our communities. This includes educating people about STIs, improving access to STI testing, and ensuring follow-up of people diagnosed with STIs and their sexual partners to prevent onward transmission.


  1. Gilbert M, Rekart ML. Recent trends in chlamydia and gonorrhea in British Columbia. BCMJ 2009 Dec;51(10):435
  2. Public Health Agency of Canada. Notifiable diseases online. [Accessed Aug 8, 2018] from: diseases.canada.ca/notifiable/
  3. Bourgeois AC, Edmunds M, Awan A, Jonah L, Varsaneux O, Siu W. HIV in Canada — Surveillance Report, 2016. Can Commun Dis Rep. 2017;43(12):248-56. Obtained from: doi.org/10.14745/ccdr.v43i12a01.
  4. Rietmeijer CA, Patnaik JL, Judson FN, Douglas JM,Jr. Increases in gonorrhea and sexual risk behaviors among men who have sex with men: a 12-year trend analysis at the Denver Metro Health Clinic. Sex Transm Dis 2003 Jul;30(7):562-567
  5. Mayer KH. Sexually transmitted diseases in men who have sex with men. Clin Infect Dis 2011 Dec;53 Suppl 3:S79-83.
  6. Khosropour CM, Dombrowski JC, Swanson F, Kerani RP, Katz DA, Barbee LA, et al. Trends in serosorting and the association with HIV/STI risk over time among men who have sex with men (MSM). J Acquir Immune Defic Syndr. 2016;72(2):189-97.
  7. Garcia JR, Reiber C, Massey SG, Merriweather AM. Sexual hookup culture: A review. Rev Gen Psychol 2012;16: 161–176. Obtained from: www.ncbi.nlm.nih.gov/pmc/articles/PMC3613286/
  8. Doherty IA, Padian NS, Marlow C, Aral SO. Determinants and Consequences of Sexual Networks as They Affect the Spread of Sexually Transmitted Infections. J Infect Dis.  2005;191 (Suppl 1):S42-5
  9. Hull P, Mao L, Prestage G, Zablotska I, De Wit J, Holt M. The use of mobile phone apps by Australian gay and bisexual men to meet sex partners: An analysis of sex-seeking repertoires and risks for HIV and STIs using behavioural surveillance data. Sex Transm Infect. 2016; 92:502 – 507.
  10. Kraus R. “Grindr, Other Dating Apps Are Working to Add STD Notification Features.” Mashable, 31 May 2018. Obtained from: mashable.com/2018/05/31/grindr-tinder-department-of-health-std-notification/
  11. Abeykoon H, Lucyk K. Sex and seniors: A perspective. Canadian Public Health Association. 2016. Ottawa, ON.  Obtained from:  hwww.cpha.ca/sex-and-seniors-perspective
  12. BC Centre for Disease Control. STI in British Columbia: Annual Surveillance Report 2016. Obtained from: www.bccdc.ca/health-professionals/data-reports/communicable-diseases
  13. Macapagal K, et al. HIV prevention fatigue and HIV treatment optimism among young men who have sex with men. AIDS Educ Prev. 2017;29(4):289–301.
  14. Peterson JL, Miner MH, Brennan DJ, Rosser BR. HIV treatment optimism and sexual risk behaviors among HIV positive African American men who have sex with men. AIDS Educ Prev 2012; 24(2), 91–101.
  15. Moore DM, Cui Z, Lachowsky NJ, Rich AJ, Roth EA, Raymond HF, Sereda P, Montaner J, Wong J, Armstrong HL, Hall D, Hogg RS. Increasing HIV treatment optimism but no changes in HIV risk behavior among men who have sex with men in Vancouver, Canada. J. Acquir. Immune Defic. Syndr. 2017;76:e98–e101
  16. Nguyen VK, Greenwald ZR, Trottier H, Cadieux M, Goyette A, Beauchemin M, et al. Incidence of sexually transmitted infections before and after preexposure prophylaxis for HIV: a cohort study. AIDS 2018; 32:523–530.