References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Yes, you can have two or more STIs at the same time. Co-infection is common because the same sexual exposure that transmits one STI can transmit another. Having one STI can also increase vulnerability to others — for example, genital inflammation from chlamydia makes HIV transmission easier. This is why comprehensive testing matters.
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Common Co-infections
| Combination | Why It Happens |
|---|---|
| Chlamydia + gonorrhoea | Both transmitted the same way; shared risk factors |
| HIV + syphilis | Common in MSM networks |
| HIV + hepatitis B or C | Shared transmission routes |
| HPV + herpes | Both spread by skin contact |
| Chlamydia + trichomoniasis | Can overlap in symptoms |
Why Co-infection Matters
- Each infection needs its own treatment
- One STI can worsen another
- Untreated co-infections compound health risks
- Comprehensive testing catches everything
How to Protect Yourself
- Get a full STI screen, not just one test
- Include HIV, syphilis, chlamydia, gonorrhoea and hepatitis
- Add throat and rectal swabs if relevant
- Use condoms and PrEP as appropriate
Read more: Silent STIs | How often to test | Single vs comprehensive tests
Frequently Asked Questions
How common is co-infection?
More common than many people think, especially in higher-risk groups.
Does one STI make me more vulnerable to others?
Yes — inflammation and immune changes increase susceptibility.
Will one treatment cure both?
Usually not — different infections need different antibiotics.
Related reading
- Blood Test for Syphilis, Hepatitis B and Hepatitis C
- Can You Get an STI From Being Fingered?
- Can You Catch an STI From a Toilet Seat?
- Can You Clear HPV Once You Have It?
- Can You Die From Hepatitis B?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
