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Chemoprophylaxis and Immunoprophylaxis as Tools to Prevent Sexually Transmitted Infections/Human Immunodeficiency Virus
*Corresponding author: Yogesh S. Marfatia, Department of Skin and VD, Smt. B.K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth, Vadodara, Gujarat, India. ym11256@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Marfatia YS, Rout P, Mayekar TA, Newadkar AD, Vardhaman VJ. Chemoprophylaxis and Immunoprophylaxis as Tools to Prevent Sexually Transmitted Infections/Human Immunodeficiency Virus. Indian J Postgrad Dermatol. 2025;3:129-37. doi: 10.25259/IJPGD_183_2025
Abstract
Sexually transmitted infections (STIs) remain a pressing global health challenge, with over one million new infections reported daily. In India, where centralised data are limited, an estimated 6% of adults acquire STIs annually, with syphilis being the most common. Beyond immediate illness, untreated STIs can lead to infertility, neonatal complications, cancers and immense psychosocial stress. Traditional approaches such as early detection, treatment and condom promotion have had limited success, particularly against asymptomatic infections and in populations facing stigma or barriers to healthcare. Shifts in sexual behaviour, including increased oral and anal intercourse, use of sex toys and reliance on emergency contraception, have contributed to rising STIs worldwide. In high-income countries, especially among men who have sex with men, decreasing condom use alongside access to human immunodeficiency virus antiretroviral therapy and pre-exposure prophylaxis (PrEP) has further driven this surge. These realities highlight the urgent need for preventive strategies beyond conventional methods. Prophylaxis of STIs is the prevention of the disease before it sets in. It can be achieved by various methods such as chemoprophylaxis or immunoprophylaxis for various sexually transmitted diseases. Chemoprophylaxis through PrEP, post-exposure prophylaxis, continued prophylaxis, periodic presumptive treatment and expedited partner therapy are proving to be highly effective. Meanwhile, immunoprophylaxis, particularly human papillomavirus and hepatitis B vaccination, has proven highly effective in reducing transmission and carcinoma risk. While prophylaxis is cost-effective and prevents disability-adjusted life years lost, challenges remain. These include adherence, drug resistance and the ‘risk compensation’ effect where perceived protection leads to riskier sexual behaviour. The way forward lies in scaling up accessible, stigma-free prevention services, ensuring country-specific clinical trials and closely monitoring antimicrobial resistance. Ultimately, a proactive, preventive approach can protect individuals and communities while reducing the long-term burden of STIs.
Keywords
Chemoprophylaxis
Immunoprophylaxis
Post-exposure prophylaxis
Pre-exposure prophylaxis
Vaccine
INTRODUCTION
Every day over one million people globally are newly diagnosed with sexually transmitted infections (STIs), making it a significant public health issue. In India, though there is a lack of proper centralised data, it is estimated that 6% of adults contract STIs every year and syphilis is the major STI, followed by chlamydia, chancroid and gonorrhoea.[1]
STIs usually lead to a significant decrease in quality of life, as untreated infections may lead to various local as well as systemic complications, including carcinomas. In the past, efforts to tackle STIs were focused mainly on detecting infections early and treating them effectively. In developed countries, especially among men who have sex with men (MSM), STI rates have climbed up, signalling a growing need for prevention strategies beyond treatment, such as prophylaxis. Even though antibiotics can cure many bacterial STIs when symptoms appear, a major challenge remains with asymptomatic cases of STIs/human immunodeficiency virus (HIV) as they go unnoticed and continue to spread. The syndromic approach is not helpful in screening and detecting asymptomatic cases and therefore not useful for case detection. Asymptomatic cases become particularly risky when sexual health awareness is low or people face obstacles accessing healthcare because these hidden infections can fuel broader transmission. Traditional contact tracing often faces difficulty, especially when sexual partners are anonymous and is further strained by limited resources, stigma and cultural barriers. Around the world, now fewer people are embracing traditional STI prevention methods, and this shift is evident in Germany, where syphilis cases have surged dramatically over the past 20 years. After reaching historic lows in the 1990s, infections began climbing steadily in the early 2000s, fuelled largely by outbreaks among men who have sex with men.[1,2]
Increased sexual exposure and the subsequent spread of STIs are also due to current societal and economic variables as well as the ease of access to cell phones and the internet. Sexual behaviour and practices have undergone a significant shift. The prevalence of oropharyngeal and anorectal STIs is barely measured, while oral and anal intercourse has become more common. The usage of sex toys and devices, which can spread STIs and cause reinfection, is becoming more and more popular. Oropharyngeal gonorrhoea has been found to occur even when urogenital gonorrhoea is absent, i.e., through tongue kissing. Anorectal gonorrhoea can spread by unprotected insertive anal sex, rimming and the practice of using saliva as a lubrication during anal intercourse. Since the introduction of anti-retroviral treatment (ART), there has been a decoupling of means of prevention of HIV from other STIs. With ART freely available and pre-exposure prophylaxis (PrEP) being promoted, many people, especially within the MSM community, may feel less need to use condoms. This relaxed approach to protection has been linked to rising cases of gonorrhoea and syphilis. At the same time, the growing use of emergency contraception as a safety net is also contributing to the continued spread of STIs.[2]
There are certain limitations of current STI preventive measures such as condoms. Condom effectively protects against body fluid-borne STIs (e.g., gonorrhoea, chlamydial urethritis) than for ulcerative infections (e.g., genital herpes, condyloma) and also female condoms are not very popular. Correct and consistent use of condom is another issue. Vaginal microbicides are substances with active pharmaceutical agents which act by interacting with the vaginal environment’s anatomy which is of a larger surface area, making it a primary target for pathogens, at the same time composed of a lactobacillus-rich microbiome consisting of antimicrobial peptides and possesses a strong immune response.[3] They are still under research and effective microbicidal agents are still not available. Except human papilloma virus (HPV) and hepatitis B virus vaccine, vaccines for common viral infection such as herpes and bacterial infection are not available. Emergency contraception protects only against pregnancy not against STIs.
Circumcision is not a common practice in India, even though back in 2007, the World Health Organization and the United Nation’s programme on HIV and acquired immunodeficiency syndrome recommended it as an extra tool to help prevent HIV.
More recently, another option is being explored using doxycycline as a self-administered preventive measure, especially for people at higher risk, like sex workers or those who cannot always access condoms or healthcare easily. In June 2024, the Centres for Disease Control (CDC) advised that healthcare providers talk to MSM and transgender women who have had a bacterial STI in the past year about doxy-post-exposure prophylaxis (PEP), giving them the choice to use it through shared decision-making.
Doxycycline’s low cost, easy availability and good safety record make it a promising choice, particularly for sex workers and others who might not always be able to negotiate condom use. However, it is not suitable for people who are pregnant or trying to conceive.[4]
Over the past 10 years, both PrEP and post exposure prophylaxis (PEP) have been gaining real traction. There is growing confidence in both antibiotics and vaccines-based prevention. These strategies often cost less than treating full-blown infections, they effectively prevent illness and they help save disability-adjusted life years. In other words, they are a real-life reminder that ‘an ounce of prevention is worth a pound of cure’.[2]
PRE-EXPOSURE PROPHYLAXIS (PREP)
PrEP is the use of medications for preventing an infection before exposure. It is easy to use, affordable and helps preventing resistance by targeting infections early plus it sidesteps the complications of advanced disease. It gives us crucial ‘lead time’, making treatment simpler and more effective in the long run.[4,5]
POST EXPOSURE PORPHYLAXIS (PEP)
PEP is the treatment initiated after a high-risk exposure. It offers significant benefits in cases of unplanned sexual intercourse such as sexual assaults and child abuse.[5]
Continued prophylaxis is midway between PrEP and PEP. It has been described in HIV in continued high-risk behaviour and sero-discordant couples, particularly in couples with male having infection and female being pregnant.[5]
PERIODIC PRESUMPTIVE TREATMENT (PPT)
It is a method in which one 1-time treatment is given for a presumed infection in a person or a group of persons who are at increased risk. PPT for STI is usually given at repeated intervals. It can be provided as syndromic case management kits, which are decided on the basis of local prevalence. It is usually advised for female sex workers/MSM. PPT takes care of asymptomatic infections.[5]
Expedited partner therapy refers to a clinical intervention in which healthcare providers give medication or a prescription for the sexual partners of the patient diagnosed with chlamydia or gonorrhoea, who are unlikely or unable to promptly seek medical care.[5]
TARGET POPULATION FOR CHEMOPROPHYLAXIS AND IMMUNOPROPHYLAXIS IN STIS
High risk behaviour (MSM, sex workers)
They usually face higher risks of STIs due to factors such as multiple sexual partners, inconsistent condom use and limited healthcare access. They also face societal stigma which demotivates them from accessing available preventive measures.[4,5]
Migrant population
They engage in sexual activities with casual partners. They usually do not have the same healthcare access or preventive resources as they would have in their usual place of residence. Their migration and lack of stable relationships can increase the risk of unprotected sex and therefore significant exposure to STIs.[4,5]
Sero-discordant couples
When one partner is positive, and the other is negative, it is necessary for the negative partner to have access to preventive measures and regular testing.[4,5]
Sexual contact of STD cases
Epidemiological treatment or contact treatment refers to treating persons who have been in sexual contact with persons diagnosed with an infectious disease. This prevents further spread of infections and reduces the chances of reinfection.[4,5] The sex partners of people with primary, secondary or early latent syphilis within 180 days must be given epidemiological treatment for early syphilis with the recommended regimen of benzathine penicillin irrespective of their clinical and serological status.
Pregnant and breastfeeding women
If a pregnant/breastfeeding female or her partner indulges in high-risk sexual behaviour, it poses different challenges. STIs can be transmitted to their babies during pregnancy or childbirth and a strategy to prevent such transmission is crucial. Chemoprophylaxis having proven safety during pregnancy/lactation should be offered.[4,5]
Victims of sexual assault/coercive sex
In such unwarranted cases, the victim may be at risk of contracting STIs, including HIV. Immediate access to emergency contraception, PEP for HIV/STIs and other medical care is necessary in such cases.[4,5]
On demand
This refers to people who may not be in high-risk groups but who require emergency or on-demand access to sexual health services, such as emergency contraception or PEP after potential exposure to HIV or other STIs. Having STI services available whenever someone needs them, in a friendly, confidential and non-judgemental way is the key. It ensures that during those critical moments when someone might feel scared or unsure, no barriers stop them from getting the care and support.[4,5]
People in correctional facilities
Persons residing in various correctional facilities have an increased prevalence of STIs, HIV and viral hepatitis, especially in age group <35 years. High-risk behaviours for contracting STIs (e.g., having unprotected sex, having multiple sex partners, substance misuse and engaging in commercial, survival or coerced sex) are prevalent among incarcerated populations.[4,5]
IV drug abusers
Person having recurrent or even occasional exposure to IV drugs are at a greater risk of contracting STIs, Hence, they form an important target group for STI prevention.
Healthcare workers/needlestick injuries
People working in healthcare setups, managing patients, majority of times without knowing their sero status, if face any needle stick injury also require PEP if the serology status is found to be positive, Hence, they should also form a part of the target group.[4,5]
CHEMOPROPHYLAXIS
PrEP in HIV
Today’s HIV prevention efforts still face many hurdles. Delays in getting tested, limited understanding of personal risk, especially among young people and women and not enough emphasis on treatment are the major factors. On top of that, low acceptance of male circumcision and the absence of a protective vaccine make prevention even harder. Risky sexual behaviours, such as unprotected sex, sexual coercion, rape and other non-consensual encounters, put women at especially high risk of contracting HIV and other STIs. This underscores the urgent need for stronger, targeted prevention strategies for HIV-negative individuals who face a higher risk of exposure.[4,5]
Treatment as prevention
The current policy of ‘Test and Treat’ in case of HIV infection was designed to achieve an epidemic goal of rendering cases non-infectious at the earliest. This is achieved by initiation of ART as and when the person is detected positive irrespective of immunologic or virologic status. This leads to viral suppression at potentially zero level within few months, thereby making the infected person non-infectious.
Various indications for PrEP in HIV include:[4-6]
A person having sexual contact with an HIV-infected person.
A gay or bisexual man who had unprotected sex or has been a STI case within the past 6 months and is not in a mutually monogamous relationship with a person who has tested HIV negative recently.
A heterosexual person who has unprotected sex with partners known to be at risk for HIV (e.g., injectable drug abusers or bisexual male partners of unknown HIV status) and is not in a mutually monogamous relationship with a person who has tested HIV-negative recently.
A person who within the past 6 months has used injected illegal drugs and shared needles.
A detailed regimen has been described in Table 1.
| Modality of regimen | Regimen |
|---|---|
| Oral regimen | Tablet Emtricitabine 200 mg along with tablet Tenofovir disoproxil fumarate 300 mg in a fixed dose combination taken daily. It is taken daily till risk remains high with a lead of at least 7 days for anal contact and 7–20 days for vaginal contact. WHO advises additional protection (e.g., condoms) for the first 7 days to allow time for the drugs to be effective. After the last episode of high risk sexual contact, regimen is continued for at least 28 days which aligns with the WHO guidelines endorsed by NACO.[4-6] |
| Injectableregimen | Cabotegravir has been FDA approved and is given as 600 mg IM injection at 4-week intervals for the first 2 doses and further doses are given at 8 weekly intervals. It is usually advised for serodiscordant couples and MSM. Pre-existing HIV infection should be checked before starting the regimen. (CDC/WHO approved, not approved as per NACO) Lenacapavir -A long-acting HIV prevention medication administered through subcutaneous injection every 6 months, shown to be 99.9% effective in preventing HIV infection is now FDA approved in June 2025 for HIV PrEP. Long-acting rilpivirine is available as once a month to twice a month intramuscular injections in high-risk people and serodiscordant couples (including MSM).[6] |
| Localised regimen | Rilpivirine and Dapivirine vaginal rings are not approved by the CDC but Dapivirine vaginal ring is recommended by the WHO as a preventive measure for women at significant risk of acquiring HIV and has received regulatory approval in various African countries and green signal from the EMA. |
AIDS: Acquired immunodeficiency syndrome, CDC: Centre for disease control, EMA: European medicines agency, FDA: Food and drugs association, HIV: Human immunodeficiency virus, MSM: Men who have sex with men, NACO: National AIDS control organisation, PrEP: Pre-exposure prophylaxis, WHO: World Health Organization
On follow-up visits, HIV testing, drug adherence counselling, behavioural risk reduction support and assessment for STI symptoms should be done at 3 monthly intervals and tests for bacterial STIs and renal function tests should be done at 6 monthly intervals.
PEP in HIV
PEP is an emergency method to abort HIV infection acquisition from occupational or non-occupational exposures to HIV infected blood or other infectious bodily fluids.
PEP is usually recommended when someone has had sexual contact within the past 72 h with a partner whose HIV status is not known and who cannot be traced, a person who has been sexually assaulted by a person with unknown HIV status and when a needle was shared to inject drugs within the last 72 h. However, PEP is not recommended for persons who are regularly exposed to HIV through high-risk sexual exposure, persons who frequently use injectable drugs; for both these situations, PrEP and continued prophylaxis are preferred.[4-6]
Regimen for PEP
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Tablet Tenofovir 300 mg + Tablet Emtricitabine 200 mg + Tablet Raltegravir 400 mg once daily (Raltegravir can be replaced with Dolutegravir 50 mg once daily.)
OR
Tablet Tenofovir 300 mg + Tablet Emtricitabine 200 mg + Tablet Darunavir 800 mg + Tablet Ritonavir 100 mg once daily.
Either regimen is acceptable with comparable success rates when started within 72 h of contact and continued for 28 days.
Indications for PrEP in other STIs
PrEP and PEP for other STIs are discussed in Tables 2 and 3.[7-10]
| STIs | Regimen |
|---|---|
| Syphilis | Injectable: Single dose intramuscular injection of Benzathine Penicillin 2.4 million IU with 1.2 million IU on each buttock. It provides up to 95% protection. This can be repeated at an interval of 3 months. Oral: Capsule Doxycycline 100 mg twice daily is administered before the high risk intercourse.[10] |
| Chlamydia | Single dose of 200 mg oral doxycycline taken before exposure gives up to 70% protection.[10] |
PrEP: Pre-exposure prophylaxis, STIs: Sexually transmitted infections
| STIs | Regimen |
|---|---|
| Herpes simplex | Tablet acyclovir 400 mg given twice daily is given as suppressive prophylactic dose to prevent the reactivation.[7] It is recommended in people having recurrent herpes (4–6 episodes of herpes infection per year). |
| Syphilis | Capsule doxycycline 100 mg once daily is given for 7 days after a high risk sexual exposure. It can be continued for months, since doxycycline resistance in Treponema is not common.[8] |
| Chancroid, gonorrhoea and chlamydia (adults with weight >45 kg) | Injection ceftriaxone 500 mg IM plus doxycycline 100 mg orally, twice daily for 7 days OR Tablet azithromycin 1 g plus Tablet cefixime 800 mg orally.[6,9] |
| Chancroid and chlamydia (children and adults with weight <45 kg) | Tablet azithromycin single oral dose (20 mg/kg) on empty stomach.[6,9] |
| Gonorrhoea (Children and adults with weight <45 kg) | Tablet cefixime 8 mg/kg of body weight as a single dose OR Injection ceftriaxone 250 mg, single dose, IM |
| T. vaginalis and bacterial vaginosis (adults with weight >45 kg) | Tablet secnidazole 2 g orally single dose OR Tablet metronidazole 2 g orally single dose OR Tablet tinidazole 2 g orally single dose.[6,9] |
| T. Vaginalis (Children and adults with weight <45 kg) | Oral metronidazole (15 mg/kg/dose) 3 times a day for 7 days.[6,9] |
PEP: Post-exposure prophylaxis, STIs: Sexually transmitted infections
PrEP users particularly transgender women often have higher risk sexual exposures, including multiple anal sex partners and condomless anal sex. This increases their vulnerability to bacterial STIs. Hence, regular STI counselling and testing should be integrated into PrEP care. Recent trials show that doxycycline prophylaxis (Doxy-PrEP/PEP) can significantly reduce new infections of chlamydia and syphilis and may also help prevent gonorrhoea, though its effectiveness depends on local resistance levels.[9]
ISSUES WITH CHEMOPROPHYLAXIS IN STIS
Peltzman effect/Risk compensation
Some people develop false sense of protection and this leads to decrease in preventive measures and therefore leads to increase in high-risk behaviour such as not using condoms. This increases the risk for other STIs, which particular PrEP/ PEP does not prevent.[4-6,9]
Drug adherence
Proper counselling and measures for adherence are recommended. Lack of proper compliance with the regimen significantly reduces effectiveness.[4-6,9]
Start-up syndrome
In HIV PrEP, when the patient is started on medications, in the initial 1-month period, some persons may have mild transient gastrointestinal side effects such as nausea, vomiting, diarrhoea or abdominal pain. Certain patients tend to discontinue the regimen or may not be compliant with it due to these symptoms. Hence, it is one of the major issues with chemoprophylaxis.[4-6,9]
Drug resistance
If PrEP is started not knowing about the HIV status of the person, the virus may develop resistance leading to difficulty in further future management.[4-6,9]
Barriers beyond the pill
Social stigma, lack of proper healthcare access and awareness are major limitations. Healthcare workers not discussing sexual orientation or gender identity also play a major role. Sometimes, high cost, certain side effects and limited infrastructure are also major issues. Delayed starting of PEP, resistant virus and further high-risk sexual exposures may lead to failure of PEP.[4-6,9]
IMMUNOPROPHYLAXIS
It is the process of preventing disease by inducing active immunity with the help of vaccines or passive immunity through the use of preformed antibodies.
HPV vaccine
HPV vaccine not only prevents cervical, vaginal, vulval, penile and anal carcinomas but also is effective against anal and genital warts. It not only has a good coverage in females but also in males hence a gender neutral approach including males is recommended. Female-only vaccination would not help MSM. Therefore, vaccination is essential for both males and females before sexual debut. This will lead to a decrease in the infectious pool of HPV. Herd immunity is seen in unvaccinated heterosexual males as a result of female vaccination. Nonavalent HPV vaccine prevents high-grade cervical lesions caused by the five additional HPVs (HPV 31, 33, 45, 52 and 58) as compared to bivalent (HPV 6, 11) and quadrivalent (HPV 6, 11, 16, 18) HPV vaccines. The ideal age for vaccination is 9–26 years.[11,12]
The detailed HPV vaccine schedule is discussed in Table 4.[11,12]
| Females of 9–14-year age group | 2 dose regimen (0, 6–12 months) |
| Females of 15–26-year age group | 3 dose regimen (0, 1–2 months, 6 months) |
| Females of 27–45-year age group | Decided by the physician based on the benefits expected |
| Females of >45-year age group | Decided by the physician based on the benefits expected |
| MSM (Target age group is <21 years) | 2 dose regimen (0, 6–12 months) |
| Pregnant females | Not recommended (pregnant females should ideally complete the course of vaccination before pregnancy, halt the course while pregnant and resume it after their delivery) |
| Breastfeeding females | Considered safe |
| Males of any age (if immunocompromised) | 3 dose regimen (0, 1–2 months, 6 months) |
HPV: Human papilloma virus, MSM: Men who have sex with men
Hepatitis B vaccine
Pre-exposure immunoprophylaxis
Hepatitis B vaccination is recommended for all unvaccinated, uninfected persons who are sexually active with more than one partner or are being evaluated or treated for a STI. Hepatitis A and B vaccines are also recommended for MSM, injectable drug abusers, persons with chronic liver disease and persons with HIV or hepatitis C infections who have not had hepatitis A or hepatitis B. Subunit vaccine 0.5 mL is given intramuscularly at 0, 1 and 6 months. It is a genetically engineered recombinant DNA vaccine.[13]
Post-exposure immunoprophylaxis
It should be initiated preferably within 24 h but can be given within 14 days of sexual exposure. Detailed regimen is discussed in Table 5.[13]
| Exposure | Recommendation in unvaccinated person | Recommendation in previously vaccinated person |
|---|---|---|
| Percutaneous (e.g., bite or needlestick) or mucosal exposure to HBsAg positive body fluids | Hepatitis B vaccine and HBIG (0.06 mL/kg) | Hepatitis B vaccine booster dose |
| Sex or needle-sharing with a HBsAg-positive person | Hepatitis B vaccine and HBIG (0.06 mL/kg) | Hepatitis B vaccine booster dose |
| Victim of sexual assault by HBsAg-positive person | Hepatitis B vaccine and HBIG (0.06 mL/kg) | Hepatitis B vaccine booster dose |
| Victim of sexual assault by a person with unknown HBsAg status | Hepatitis B vaccine | No treatment |
| Percutaneous (e.g., bite or needlestick) or mucosal exposure to infectious body fluids of a person with unknown HBsAg status | Hepatitis B vaccine | No treatment |
PEP: Post-exposure prophylaxis, HBsAg: Hepatitis B surface antigen, HBIG: Hepatitis B immune globulin
Mpox vaccine
Virus causing mpox is related to smallpox virus. JYNNEOS is a two-dose vaccine developed to protect against mpox and smallpox. Both doses of the vaccine are needed for protection against mpox after 4-week interval (CDC recommendation). It is given as PEP to individuals ideally within 4 days of exposure but may be given till 14 days after exposure.[14]
Current status of vaccines for other STIs
Researchers are actively working on developing vaccines to protect against several STIs, each at different stages of progress. A vaccine for trichomoniasis is still in the early discovery stage, while one for syphilis is being tested in preclinical studies. The chlamydia vaccine has reached Phase I clinical trials, the herpes simplex virus type 2 (HSV-2) vaccine is in Phase II trials and a gonorrhoea vaccine is in the more advanced Phase III stage, bringing it closer to potential public use. Table 6 denotes vaccines for HSV under trial.[15,16]
| Vaccine | Type | Developer | Current status | Key points |
|---|---|---|---|---|
| 0∆NLS | Live-attenuated vaccine | Rational Vaccines | Clinical trials-Phase 1/2 | Superior efficacy compared with Disialoganglioside-based vaccines (e.g., Herpevac) in protecting guinea pigs from lethal challenges. |
| mRNA-1608 | mRNA vaccine | Moderna | Clinical trials-Phase 1/2 | Achieved 85–100% reduction in genital disease in animal models. |
| Codon modified and optimised plasmid-1 | DNA vaccine | Anteris Technologies | Clinical trials-Phase 2 | Ongoing trials; DNA platform aims for durable immune response. |
| gD2-based vaccines (Herpevac, etc.) | Subunit vaccines | Various | Clinical trials-Phase 1/2 | Lower efficacy; outperformed by live-attenuated approaches in preclinical models. |
HSV: herpes simplex virus, mRNA: Messenger ribonucleic acid
Issues with vaccines for STIs prevention
These vaccines are developed to improve mucosal immune response, but systemic immunisation may induce weak mucosal immunity. Mucosa of the genital system has a deficiency of properly designed lymphatic system leading to poor capacity to prevent STIs.[15]
CONCLUSION
While antibiotics can effectively cure many bacterial STIs once symptoms appear, a big challenge lies in infections that show no symptoms. These silent infections often go undetected, allowing them to spread unnoticed. The syndromic approach, which relies on treating based on visible symptoms, falls short in identifying such asymptomatic cases, making it less effective for true case detection. Adding to this concern, changing sexual behaviours and a rise in high-risk sexual practices have further increased the risk of transmission. Chemoprophylaxis and immunoprophylaxis can play a crucial role in preventing STIs in diverse situations. Initiating PrEP and PEP in an aggressive manner at the right time offers clear advantages in reducing illness and disability. They are affordable and cost-effective. The need of the hour is to prioritise country-specific, well-run clinical trials, especially among those at highest risk to confirm the safety and effectiveness of these regimens. Meanwhile, keeping a close watch on antimicrobial resistance is essential to ensure that these tools remain effective for the long term.
MCQs
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Ravi, a 27-year-old MSM, recently had unprotected sex and is worried about HIV. He asks about PrEP. According to the WHO guidelines, how long should he continue PrEP after his last high-risk contact?
7 days
14 days
28 days
3 months
-
Meena, a 32-year-old sex worker, often struggles with condom negotiation. India is exploring a new preventive option for women like her using an affordable antibiotic. Which drug is it?
Azithromycin
Ceftriaxone
Doxycycline
Acyclovir
-
Which of the following is NOT prevented effectively by condoms?
Gonorrhoea
Chlamydia
Syphilis ulcers
HIV
-
A young woman comes worried after having unprotected sex with a partner recently diagnosed with syphilis. Which single-dose injection can protect her as PrEP?
Injection Ceftriaxone 500 mg
Injection Benzathine Penicillin 2.4 million IU
Injection Rilpivirine
Injection Cabotegravir
-
Which of the following represents risk compensation behaviour in the context of STI prevention?
Using condoms consistently
Stopping condom use after starting PrEP
Taking antibiotics only when sick
Completing full vaccine course
-
A 12-year-old girl is brought by her mother for HPV vaccination. What is the recommended dose schedule?
Single dose
2 doses (0, 6–12 months)
3 doses (0, 1, 6 months)
Annual booster
-
A 20-year-old MSM who never received hepatitis B vaccination presents for STI check-up. What is the correct pre-exposure immunoprophylaxis schedule?
Single dose IM
0, 1 and 6 months (3 doses)
0 and 6 months (2 doses)
2 doses at 0 and 12 months
-
A 30-year-old man reports recurrent genital herpes with 5 flare-ups in the past year. Which suppressive prophylaxis is most appropriate?
Acyclovir 400 mg twice daily
Benzathine penicillin 2.4 million IU
Azithromycin 1 g single dose
Ceftriaxone 500 mg IM
-
Rohit, a young MSM, says he avoids condoms because he is on HIV PrEP. What counselling point should his doctor stress?
PrEP also prevents syphilis and gonorrhea
Condoms are not needed if PrEP is used
PrEP only protects against HIV, but not other STIs
He should switch to HPV vaccination
-
In a sexual assault case, a clinician must act quickly. Which is the most appropriate immediate intervention within 72 h?
PrEP for HIV only
PEP for HIV/STIs, emergency contraception and medical support
Condoms and counselling alone
HPV and hepatitis B vaccines only
Answer Key
1-c, 2-c, 3-c, 4-b, 5-b, 6-b, 7-b, 8-a, 9-c, 10-b
Ethical approval:
Institutional review board approval is not required.
Declaration of patient consent:
Patient’s consent not required as there are no patients in this study.
Conflicts of interest:
Dr. Yogesh S Marfatia is on the editorial board of this journal.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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