The Most Common Sexually Transmitted Infections In The UK


Anyone may contract a sexually transmitted infection (STI), though the risk is greater if you are sexually active and having unprotected sex. In the UK, many people underestimate the risk of STIs and do not make frequent or proper use of sexual health clinics for STI healthcare services.

STIs are also a significant health concern that impacts the sexual and reproductive health of the worldwide population. They can have long-term consequences if not diagnosed and treated at the earliest opportunity; though not all STIs are curable, so it is essential that you are aware of the risk factors and prevention methods for STIs. 

What is a sexually transmitted infection?

Sexually transmitted infection (STI) or sexually transmitted disease (STD) is an infection that is transferred from one sexual partner to another through the vaginal, oral or anal route. However, some infections may be transferred to a newborn from an infected mother during pregnancy, childbirth, and breastfeeding.

How common are sexually transmitted infections?

  • Every day, more than 1 million people are infected with STIs worldwide
  • In 2020, World Health Organisation (WHO) estimated that the 4 most common STIs- chlamydia, gonorrhoea, syphilis and trichomonas- account for 374 million new infections
  • In England, there is an increase of 24% in STIs compared to 2021
  • The number of STI diagnoses in young adults aged 15 to 24 has increased by 26% since 2021 in England
  • People assigned-male-at-birth (AMAB) who have with sex with others AMAB, young people, and black ethnic minorities are most likely to contract STIs2

Common sexually transmitted infections in the UK

The WHO reports that more than 30 species of bacteria, viruses, and parasites transmit infections through sexual contact. Despite the existence of numerous organisms that cause STIs, very few are responsible for significant STIs in the UK. The prevalence of STIs in the UK throughout the past century has been impacted by significant changes in society's social, economic, and demographic landscapes.2 

There has been an alarming rise in STIs in the UK since the COVID-19 pandemic rules have relaxed. Here are some of the most common STIs in the UK that warrant immediate public attention:

The key STI data as per UK Health Security Agency (UKHSA) states that:

  • Since 2021, there has been a significant rise in STIs
  • Gonorrhoea prevalence has increased by 50%, chlamydia by 24% and syphilis by 15%
  • There is a surge of 8% in chlamydia in young people despite no increase in testing
  • Sexual health services have increased to 8% since 2021

Causes and risk factors

Numerous factors contribute to STIs (see Table 1), and it is possible for infections to coexist in an individual.

Table 1: Pathogens causing sexually transmitted infections.3,4

Causative organismSexually transmitted infections
BacteriaChlamydia, Gonorrhoea, Syphilis and Mycoplasma genitalium
VirusGenital herpes, Genital warts, HIV and Hepatitis B virus
InfestationScabies and Pubic lice

Understanding the cause of STIs is required for the prevention and timely management of STIs.

Risk factors for sexually transmitted infections

A sexually active person is more exposed to acquiring STIs from the infected partner. Also, people assigned-female-at-birth (AFAB) or anyone with a female urogenital system is more vulnerable to STIs due to infection via the thin vaginal mucosa.3 

Some important factors that contribute to infection risk include:

  • Unprotected sex
  • Multiple sexual partners
  • Sexual contact with infected person or sex workers
  • Rupture of condom during sex
  • High-risk groups (such as people AFAB or black ethnic minority groups)
  • Previous history of STI
  • Inadequate awareness of pre-exposure protection and safe sex practices
  • Drug and alcohol abuse (less common)1,5

Signs and symptoms

The symptoms of an STI can manifest within a few days to weeks, or even months, depending on the type of infection. A substantial number of people show no symptoms even after testing positive for an STI - the probability of infection being asymptomatic depends on the site of entry of infection and the type of organism causing it.6

Similarly, the severity of the STI may vary based on the type of infection. The most common signs and symptoms that indicate that you may have STI include:

  • Unusual discharge from the vagina or penis
  • Fever 
  • Enlarged regional lymph nodes
  • Pain while passing urine or stool
  • Growths or warty lesions near the vagina, anus, or mouth
  • Abnormal vaginal bleeding
  • Painful genital sores and ulcers
  • Pain in the abdomen
  • Rashes all over the body3,6,7

STIs may progress to give you serious complications. The infection can be transmitted by an asymptomatic person to a sexual partner, therefore, you are advised to take immediate medical help if you have had unprotected sex or have engaged in any high-risk behaviour.


The increase in STIs, particularly in countries like the UK where free services are available, poses a significant threat to already overwhelmed health clinics. This added burden must be addressed promptly to avoid further strain on the healthcare system. Thankfully, there is plenty you can do to manage your own risk and help the growing burden of STIs in the UK.

Testing and screening are crucial steps for preventing and managing STIs, as most cases show no symptoms. If you are sexually active you should attend your local sexual health clinic for regular checkups, regardless of your sexual orientation, number of sexual partners or contraception methods used. If you’ve been diagnosed with an STI you should also inform your recent sexual partner(s) so they can take their own test and prevent the further spread of any potential infection.2

Diagnosis of STIs

Symptoms of infection may overlap due to the co-infections with other STIs. Therefore, diagnosing STDs needs a multidisciplinary approach. This often  includes:

  • A thorough medical history (including information about sexual behaviour)
  • Physical examination to look for features suggestive of an STI3,6,7

Laboratory investigations that may be used to diagnose an STI include:

  • Complete blood count
  • Routine urine examination
  • Microscopic examination of discharge 
  • Serological test known as an immunoassay (analysing bodily fluid to detect a specific organism)
  • Laboratory culture - taking a sample of blood, urine, or discharge from sores and ulcers and identifying the causative organism
  • Nucleic acid amplification testing (NAAT) - a type of genetic test that has improved the diagnosis of STIs in recent years3,6,7


Early diagnosis and prompt treatment are crucial for preventing complications and reducing the potential risk of transmission. There are different treatment approaches to STIs based on the type of infection and severity. To effectively treat STIs, it is essential to consider the following methods:

  • Antibiotics - STIs such as chlamydia, syphilis, and gonorrhoea are treated using antibiotics
  • Antiviral therapy - effective in managing herpes and hepatitis infections
  • Antiretroviral treatment - can help reduce the viral load and limit the transmission of the HIV virus (a rule of thumb: undetectable = untransmittable) 
  • Surgical treatment - to remove genital warts
  • Supportive care - such as therapy to manage your mental health and overall well-being
  • Behaviour counselling - counselling sessions can help reduce the incidence of STIs in people who have a history of engaging in or who are more likely to engage in high-risk behaviour6,7,8

It is advised that your sexual partners also take medical tests and treatment. Additionally, assessments are conducted to evaluate the effectiveness of treatment through follow-up evaluations.6

In England, individuals who engage in recognized risky behaviours are strongly recommended to undergo regular testing for HIV and STIs. The National Chlamydia Screening Programme offers opportunistic screening to sexually active young individuals and suggests that anyone under 25 undergo testing.1


If left undiagnosed and untreated, common STIs may cause long-term health problems or complications such as:


Can I have STI without any symptoms?

Yes, you can have STI without any symptoms.

  • Around 50% of women with gonorrhoea show no symptoms
  • Approximately 50% of men and 70% of women do not display any signs of a chlamydia infection
  • About 50% of men and women who contract trichomoniasis do not experience any symptoms

Can I protect myself from STIs?

You can reduce the risk of contracting an STI by various methods:

  • Safe sex practices like the use of condoms/barriers and practising good hygiene such as cleaning and avoiding sharing sex toys
  • Limiting multiple sexual partners
  • Vaccination against HPV and Hepatitis B could help in limiting the spread of infections
  • Extra hygiene precautions when open wounds or broken skin in and around the genitalia5,10

If I have concerns about STIs, what should I do?

If you're based in the UK, you can contact sexual health clinics for confidential consultations. It is a safe and supportive space to discuss any concerns regarding STIs.

You can visit these clinics without a prior appointment for services such as testing, treatment and getting information related to STIs. Some clinics in the UK also offer home testing kits.


STIs pose a serious public health threat on a global scale. Being informed about the various symptoms, tests and treatment options available in the UK is crucial for prompt and effective intervention. Taking proactive measures like safe-sex practices can significantly lower the chances of infection transmission. STI symptoms depend on what bacteria, virus or parasite caused the infection, though many STI cases do not exhibit symptoms. Those in high-risk groups need to get tested regularly to prevent transmission - it is imperative that both the infected individual and their sexual partners undergo testing to eliminate the possibility of STIs. Treatment options include antibiotics and antiviral therapy for common STIs and preventative vaccinations against HPV and Hepatitis B virus. It is important to take steps to prevent contracting any STIs and to treat any current infections to avoid complications.


  1. Clifton S, Mercer CH, Sonnenberg P, Tanton C, Field N, Gravningen K, et al. STI risk perception in the British population and how it relates to sexual behaviour and STI healthcare use: Findings from a cross-sectional survey (Natsal-3). EClinicalMedicine [Internet]. 2018;2–3:29–36. Available from:
  2. Hughes G, Field N. The epidemiology of sexually transmitted infections in the UK: impact of behavior, services and interventions. Future Microbiol [Internet]. 2015;10(1):35–51. Available from:
  3. Van Gerwen OT, Muzny CA, Marrazzo JM. Sexually transmitted infections and female reproductive health. Nat Microbiol [Internet]. 2022;7(8):1116–26 Available from:
  4. Melanie L, Yarbrough C-AD. The ABCs of STIs: An Update on Sexually Transmitted Infections. Clinical Chemistry. 2016;62(6):811–23
  5. Sherwal BL, Nayyar C, Chander R, Gupta P. Evaluation of risk factors in patients attending STI clinic in a tertiary care hospital in North India. Indian J Sex Transm Dis [Internet]. 2015;36(1):48. Available from:
  6. Wagenlehner FME, Brockmeyer NH, Discher T, Friese K, Wichelhaus TA. The presentation, diagnosis, and treatment of sexually transmitted infections. Dtsch Arztebl Int [Internet]. 2016; Available from:
  7. Fuchs W, Brockmeyer NH. Sexually transmitted infections: CME Article. J Dtsch Dermatol Ges [Internet]. 2014;12(6):451–64. Available from:
  8.  Lin JS, Whitlock E, O’Connor E, Bauer V. Behavioral counseling to prevent sexually transmitted infections: a systematic review for the U.S. Preventive Services Task Force. Ann Intern Med [Internet]. 2008;149(7):497–508, W96-9. Available from:
  9. Tsevat DG, Wiesenfeld HC, Parks C, Peipert JF. Sexually transmitted diseases and infertility. Am J Obstet Gynecol [Internet]. 2017;216(1):1–9. Available from:
  10. Schiller JT, Lowy DR. Vaccines to prevent infections by oncoviruses. Annu Rev Microbiol [Internet]. 2010;64(1):23–41. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Rajni Sarma

MBBS, MD from North-Eastern Hill University, India
MSc in Molecular Pathology of Cancer, Queen's University, Belfast, UK

I worked as a medical doctor for almost eight years before applying to Queen’s University Belfast for MSc in Molecular Pathology of Cancer. My outstanding verbal and demonstrative skills have helped me to get distinction in my master’s program.

However, I found my true passion in medical writing. Therefore, after I graduated from Queen’s University, I decided not to join any laboratory but to restart my career as a medical writer.

The topics that intrigue me are haematology, oncology, rare diseases, immunology, gynaecology, molecular pathology, targeted therapy, and precision medicine. I am currently an intern at Klarity and a volunteer medical writer for a health and wellness website.

Leave a Reply

Your email address will not be published. Required fields are marked * presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818