What is Preexposure Prophylaxis for HIV Prevention?
HIV, or Human Immunodeficiency Virus, isn’t curable, but it can be prevented. Still, in 2022, about 1.3 million people globally, including approximately 130,000 children got HIV. The United States reported over 36,000 new HIV cases in 2021. HIV is mainly transmitted through heterosexual contact in Africa, while in other regions, it’s mostly spread through sexual contact between males. People who inject drugs or transgender people often have the highest rates of HIV.
A method of preventing HIV is by using preexposure prophylaxis, or PrEP. This is a daily medication that people at high risk of HIV can take to prevent the virus. The World Health Organization (WHO) and the United States Centers for Disease Control and Prevention (CDC) recommend PrEP as part of a combination of HIV prevention methods. Regular use of oral PrEP can reduce the risk of getting HIV by up to 92% compared to not taking anything at all. There is also an injectable version of PrEP, which can reduce the risk by about 70%.
In 2015, the WHO recommended PrEP to anyone at substantial risk for HIV infection. It is vital, especially in areas with a high number of HIV cases, to reduce the global spread of HIV. However, it’s insufficiently used. More than 2.5 million people worldwide used PrEP at least once in 2022, but that’s still far below the target of 10 million people.
In general, anyone of any age, gender, race, or social status can get HIV. Specific groups at higher risk, such as men who have sex with men, transgender individuals, sex workers, and people who share drug injection equipment should be informed about PrEP. PrEP should ideally be started on the same day a person at high risk for HIV consults healthcare services, after ruling out active HIV and testing kidney function.
Staying committed to regular healthcare check-ups, support, reducing risk factors, and counseling to ensure proper medication use is necessary when on PrEP. Not taking the medication as advised can increase the risk of contracting HIV. However, PrEP is not widely available or non-existent in certain countries, and even in those that do have PrEP programs, availability remains limited for those at highest risk. Understanding the local situation and using this information to build services catered to the local population is critical.
PrEP plays a crucial role in clinical HIV prevention and health maintenance. Identifying those at risk, providing treatment options, monitoring, managing side effects, client support, and improving healthcare outcomes are all necessary for HIV prevention. The ultimate goal is to provide maximum benefits to those most at risk.
For more information on how HIV is transmitted, strategies for at-risk populations, implementation considerations for specific populations, and select public health measures, you can check out StatPearls’ topic on HIV Prevention.
What Causes Preexposure Prophylaxis for HIV Prevention?
HIV, a virus that primarily attacks the immune cells (CD4+ T cells and macrophages), can lead to a long-term, generally symptomless infection, and eventually to a serious condition called acquired immunodeficiency syndrome (AIDS). This is a result of the immune system slowly getting destroyed due to the loss of CD4+ cells. The amount of HIV in the body is very high during the initial stages. It decreases briefly and then rises again over time. Because of certain effective therapies, HIV is now regarded as a manageable long-term disease. However, it remains a major global health issue due to social and health inequalities.
Preventive measures, like pre-exposure prophylaxis (PrEP), are crucial for reducing the impact on individuals, communities, and healthcare systems. The World Health Organization (WHO) recommends PrEP for anyone highly likely to contract HIV. The significance of PrEP stems from multiple factors – the long-term effects of HIV, limitations of other prevention methods, and proven effectiveness and efficiency of PrEP.
In 2022, the WHO estimated more than 630,000 deaths due to HIV-related causes. About 39 million people worldwide live with HIV, with two-thirds being found in Africa. According to the CDC, around 1.2 million people in the U.S. were living with HIV at the end of 2021. Appropriate treatment can enable long-term survival, but it can also be costly, especially in areas with limited resources. People with low CD4+ cell count, even when under treatment, may be at a higher risk of new or recurring infections. HIV treatment can also trigger side effects, interact with other drugs, and cause the virus to become resistant.
Different prevention options for HIV are necessary to provide suitable choices for all high-risk individuals. Constant use of HIV medications and maintaining an undetectable viral load can prevent transmission to sexual partners. However, not everyone is aware of their HIV status and is able to maintain a consistent medication regime or achieve complete viral suppression. Behavioral strategies somewhat lower the risk of HIV, though they do not eliminate it fully. Condoms can reduce HIV transmission by more than 70% if used consistently by couples where one partner is HIV positive and the other is not. However, not everyone can ensure its consistent use, particularly women and girls. Improving knowledge about individual risk levels can help increase the uptake of PrEP.
PrEP offers protection for individuals who may not be able to prevent exposure to HIV through other methods, providing an extra layer of protection if other methods are also used. This is crucial because the development of an HIV vaccine has experienced setbacks. PrEP is less expensive and more straightforward way to prevent HIV in high-risk groups, compared to treatment. People who consistently take oral PrEP have up to 92% lower risk of HIV compared to those who don’t use it. The use of the long-acting injectable PrEP, cabotegravir, was approved in the U.S. in 2021, and has been shown to decrease the chance of contracting HIV through sexual transmission.
When appropriately used by individuals at risk of contracting HIV, PrEP has a significant impact on reducing the transmission rates at the population level. Studies have shown that the behavior of people taking PrEP doesn’t often change to involve more risky sexual practices. Although some perceived behavior modifications have been noted in certain groups, including adolescents and young people.
PrEP is cheaper than treatment for HIV infection. The PrEP regimen is given to high-risk individuals and is used daily until the risk decreases, whereas people diagnosed with HIV need to take medication for life. Despite the cost-effectiveness of PrEP, it’s still not a universally available preventative measure.
Moreover, it’s worth noting that the effectiveness of PrEP varies with adherence levels. For more information on HIV and how it affects the body, you can visit the topic “HIV and AIDS.”
Risk Factors and Frequency for Preexposure Prophylaxis for HIV Prevention
In 2022, around 1.3 million people worldwide were infected with HIV, with the highest number of cases being reported in Eastern and Southern Africa, Asia and the Pacific, Eastern Europe and Central Asia, and Western and Central Africa. Most new infections are due to sexual transmission, with anal intercourse carrying the highest risk. Injection drug use also poses a significant risk of transmission.
The rate of new HIV infections has fallen by 38% between 2010 and 2022, with a significant decrease seen in children. The HIV rate in Africa has dropped significantly, gone down three-fold in the same period, especially in Eastern and Southern Africa.
In 2021, over 36,000 people in the United States contracted HIV. The majority were adolescent and adult men, with sex between men accounting for two-thirds of new HIV diagnoses. Heterosexual contact and intravenous drug use were also significant modes of transmission. However, efforts must be increased worldwide to prevent HIV, particularly in Africa, where the rates are much higher compared to the rest of the world, with adolescent girls and young women being the most affected.
- In some areas, such as Eastern Europe, Central Asia, and the Middle East and North Africa, the number of new cases is on the rise.
- The World Health Organization and UNAIDS have identified several high-risk groups, such as men having sex with other men, injection drug users and sex workers, where PrEP (HIV prevention medication) should be focused
- Men who have sex with men have an 11 times higher risk of getting HIV than others, especially in lower-income countries. This group has the highest HIV rate in the U.S. and most countries outside Africa.
- People who inject drugs have a seven times higher HIV prevalence than the general population.
- Those engaged in sex work have a four times higher rate compared to others, with this risk being up to 30 times greater in some cases.
- Transgender people have a 14 times higher rate of HIV than the general population. Other groups, such as adolescent boys and young men, have also shown an increase in prevalence.
In 2022, more than 2.5 million people worldwide used PrEP at least once, which is a significant improvement from around 233,000 in 2019. Despite this progress, PrEP is still underutilized, especially in regions with the highest rates of HIV.
Overall, progress in HIV prevention has stalled or even regressed in some areas between 2010 and 2022. Barriers such as lack of awareness, unavailability of medications, or discrimination can hinder the use of PrEP.
Signs and Symptoms of Preexposure Prophylaxis for HIV Prevention
Doctors should routinely ask patients for a detailed history of their sexual and drug use habits to assess the risk of HIV and other infections. This should include asking about the type and frequency of sexual and drug use practices, preventive measures, whether they share drug use equipment, the number of sexual partners, and the HIV status of any partner(s). It’s also crucial to find out if the patient’s partners belong to a group with high HIV prevalence. The doctor should inquire about potential signs of sexually transmitted infections, and the person’s history of hepatitis and hepatitis vaccination status. For women and transgender men who are able to have children, the possibility of pregnancy should also be discussed. Other factors to consider include partners from areas with high infection rates and the use of illegal drugs and alcohol.
All adults and teenagers who are sexually active or use illegal drugs and who don’t already have HIV should be informed about how to prevent the infection, including Pre-Exposure Prophylaxis (PrEP). However, each person’s situation is unique, so advice should be personalized according to their specific risks and preferences. If a person is determined to be at high risk of HIV infection and does not currently have the virus, they should be offered PrEP.
When starting a patient on PrEP, doctors need to take a comprehensive medical history and conduct a physical assessment. This is to rule out any health conditions that may impact which HIV prevention drug would be best for the patient, such as bone loss, kidney disease, and heart risk factors, including smoking. Weight is important, as PrEP isn’t suitable for individuals under 77 pounds, and certain treatments may cause weight gain. Checking baseline blood pressure can predict future heart risk. Understanding the person’s personal and social circumstances can highlight any problems they might face in sticking to treatment, indicating the need for extra support.
Evidence on the additional benefits of PrEP for people in a monogamous relationship with an HIV-positive partner who is taking medication and has an undetectable viral load is limited. The medication consistency and viral suppression of the partner and the certainty of these elements will inform any decisions about PrEP use. To help assess the risk, estimates of local HIV prevalence in the United States are available from AIDSVu or the CDC.
Testing for Preexposure Prophylaxis for HIV Prevention
If you’ve requested or are considering HIV prevention medication (known as PrEP), the first step is an HIV test. It’s vital to confirm that you do not have HIV within 7 days before starting, restarting, or continuing this medication. This precaution helps prevent the medication from interfering with the treatment of an existing HIV infection, which could make future treatments challenging. It’s important to remember that test results that you report yourself or that come from anonymous sources are not acceptable.
When testing for HIV, ideally an antigen-antibody test is suggested because these tests can identify HIV sooner than those that only test for antibodies. Tests done in a lab are the most accurate, and can identify HIV within 18 to 24 days after exposure. Rapid fingerstick antigen-antibody tests are useful too, as they can detect the virus 18 to 90 days after exposure and can provide immediate results. However, rapid oral fluid tests aren’t recommended for PrEP due to their lower accuracy in detecting recent or acute infections.
If you’ve taken oral PrEP as a postexposure prophylaxis (which can help prevent HIV after a potential exposure) in the last three months, or the medication cabotegravir in the last twelve months, both an antigen-antibody test and an HIV RNA test (which checks for the genetic material of HIV) should be carried out. If you’ve recently been exposed to a high-risk event, such as a broken condom during sex with an HIV-positive partner, or needle-sharing when using drugs, a test should also be run that can detect HIV within 10 to 33 days after exposure.
Further testing is required once a decision has been made to begin PrEP, to ensure HIV negativity and identify potential risk factors for complications. These tests should be carried out promptly to minimize the time period when you might be at risk of contracting HIV. They include a lab-based HIV antigen-antibody test, Hepatitis B serology (to confirm the presence of Hepatitis B), Hepatitis C serology (for people who have sex with men, transgender women, and people who inject drugs), and sexually transmitted infection tests, amongst others. Checking kidney function and lipid profile are also key, as long-term use of PrEP can potentially impact these. Also, note that DEXA scans for bone density are not recommended for PrEP initiation or monitoring.
For details on when to begin treatment and what monitoring is required while on PrEP, please refer to the ‘Treatment’ section below.
Treatment Options for Preexposure Prophylaxis for HIV Prevention
Antiretroviral medications, also known as PrEP, play a significant role in reducing the risk of HIV. These drugs are offered, based on the doctor’s assessment, to individuals who are at high risk according to local, state, or national guidelines. Though guidelines may be set by authorities such as the World Health Organization or other regulatory bodies, doctors will make their final decisions considering local health patterns and individual risk factors.
Guidelines for using PrEP can frequently change as more knowledge becomes available, and new medicines are introduced. In the United States for instance, recommendations were updated in 2021 by the Centers for Disease Control and Prevention (CDC) and in 2023 by the US Preventive Services Task Force. Both bodies recommend offering PrEP to those who had vaginal or anal sex in the past six months and carry risk factors like a partner with HIV, a sexually transmitted infection contracted in the last six months, or a history of inconsistent or no condom use with partners of unknown HIV status. It’s also recommended for people who inject drugs, sharing injection equipment or having a partner with HIV.
PrEP is useful in cases of sexual and drug-related behaviors that are not typically openly discussed due to fear or stigma. Therefore, it should be provided to all patients who request it, regardless of their disclosed risk factors.
There are currently three recommended PrEP drugs in the United States. These include TDF/FTC, to tenofovir alafenamide (TAF/FTC), and long-acting cabotegravir. Doctors will choose the most suitable drug for an individual, considering their risk factor profile, health conditions, preference for oral or injectable medications, the potential side effects, and the cost factor if it’s not covered by insurance.
The option of medications depends on the conditions. For instance, the drug TDF/FTC can be taken as a daily oral dose by everyone at risk who weighs at least 35 kg, including pregnant or breastfeeding individuals. TAF/FTC can be used as a daily oral alternative for cisgender men and others who don’t engage in vaginal sex. Studies show that the effectiveness of TAF/FTC is equal to TDF/FTC.
In 2021, the World Health Organization also announced a recommended medication known as the dapivirine vaginal ring for women. However, it’s not accepted by the Food and Drug Administration and is not available in the United States.
For patients with renal-related issues or those who face difficulties with daily oral medications, an injectable version, cabotegravir which involves a gluteal injection every two months might be a preferred choice.
PrEP should be started as soon as possible for any person at risk. Starting PrEP may depend on some circumstances, such as the time needed for the patient to decide, additional laboratory tests for HIV, or a need for more information related to the patient’s medical conditions.
Continual monitoring is required to ensure the treatment helps without causing harm. In the case of oral PrEP courses, patients would need to undergo an HIV antigen/antibody test every three months or tests for syphilis, gonorrhea, and chlamydia every six months.
Adherence to the medications is critical for the effectiveness of PrEP. Challenges for adherence can include a variety of factors like lack of insurance, fear of societal stigma, or other uncontrollable factors. Therefore, it’s essential that medical practitioners closely monitor a patient’s compliance and help overcome any identified barriers. On the other hand, a regular injection form of the medication cabotegravir might be easier for patients due to its infrequent dosage, but it does mandate consistent healthcare appointments.
Specific attention and care are needed when working with patients who have a substance use disorder. Such individuals should be offered PrEP and should be connected with further drug treatment services to reduce the risk of HIV from needle sharing.
What else can Preexposure Prophylaxis for HIV Prevention be?
Before a person starts using PrEP, a treatment used to prevent HIV, it is crucial to make sure they do not already have HIV. This involves performing an HIV test. If there’s a likelihood of recent exposure to the virus, or symptoms suggesting acute HIV, a test to identify the virus’s genetic material (nucleic acid amplification test) is necessary. HIV testing should be repeated throughout the PrEP treatment; specifically, before each prescription refill or injection.
People who are at risk for HIV often have other risk factors that can affect their health. These factors may vary based on the patient’s personal and medical history, and their current health condition. It’s essential to consider these factors and provide the appropriate care, which may include:
- Sexually transmitted infections: If there are signs or symptoms, or risks for sexually transmitted infections, provide advice on how to prevent transmission and repeat testing as required.
- Diseases from sharing needles or other drug-related complications: Check for signs and symptoms of infections in the heart or soft tissues and advise on safer drug practices and when to seek treatment. If necessary, refer the patient for drug addiction treatment.
- Socioeconomic issues: Look for signs of intimate partner violence, homelessness, social stigma, or discrimination and direct the person to the suitable support services when needed.
- Mental health concerns: Mental health problems may have contributed to increased HIV risk or may hamper the effectiveness of PrEP. Depending on the individual’s condition and the resources of the healthcare team, counseling, medication, or referrals for specialist care may be the appropriate response.
What to expect with Preexposure Prophylaxis for HIV Prevention
While HIV cannot be cured, individuals who are infected can still live long, healthy lives. This is made possible due to modern medicines known as highly active antiretroviral therapies. If someone at risk of HIV infection seeks prevention and can stick to their treatment plan, they have an excellent chance of preventing the infection.
An oral medication called PrEP is around 99% effective in preventing HIV if taken consistently as prescribed. However, its effectiveness drops if the medication isn’t taken correctly or consistently. According to the Centers for Disease Control and Prevention, not sticking to the treatment plan can greatly decrease its effectiveness.
Scientific studies have shown that if people take the medication at least 70% of the time, they reduce their risk of getting HIV by about 73%. Taking it 40-70% of the time reduces the risk by about half. But taking it less than 40% of the time doesn’t significantly lower the risk.
Possible Complications When Diagnosed with Preexposure Prophylaxis for HIV Prevention
Tenofovir drugs are mostly well accepted by the body with 94% of patients reporting some kind of side effects. About 10% of individuals starting their PrEP medication might commonly experience a “startup syndrome” which involve symptoms such as headache, nausea, and stomach discomfort during the first month. Over-the-counter medications are effective in managing these symptoms. Some patients might also notice weight gain during this period and it’s recommended for them to adopt appropriate lifestyle changes to manage weight gain.
Significant Side Effects
- Startup syndrome
- Weight gain
Studies revealed that young men taking oral PrEP might experience a decrease in bone density, with those aged between 15 and 19 being more sensitive. This condition improved 48 weeks after the studies were completed, however, younger men continued to experience this decline.
About 7% of patients reported severe side effects, with between 1.5% and 1.9% needing to stop the medication due to these events. A few patients might experience a rare acute kidney injury from tenofovir-based medications, clinicians should advise patients of the possible signs and advise promptly seeking medical help if they occur.
Long-term cabotegravir and TDF/FTC showed similar risks of severe side effects, with no difference appearing in serious kidney or liver issues, the need to discontinue therapy due to liver events, or sexually transmitted infections. However, 81.4% of patients receiving cabotegravir reported injection site reactions including pain, tenderness, and hardness. These reactions were typically mild and naturally disappeared, usually after the first 2 to 3 injections.
Potential for Drug Interactions
Prescribed tenofovir formulas can interact with several drugs, including those often recommended alongside PrEP; meaning, they should not be taken together. Tenofovir alafenamide should not be coadministered with St. John’s Wort due to possible decreased TAF concentrations.
Meanwhile, TDF might have increased serum concentrations when co-administered with certain antiretrovirals, high-dose, or multiple nonsteroidal anti-inflammatory drugs, and other medications that impact kidney function. Other drugs should not be taken with TDF as their interaction may cause significant damage to the kidney.
No noteworthy interactions have been discovered when TDF or TAF is coadministered with buprenorphine, methadone, or oral contraceptives, so dosage adjustments are not needed. There’s currently limited research data available on interactions with feminizing hormones.
Finally, HIV infection while on PrEP is usually a result of medication non-adherence. Non-adherence could be due to a lack of awareness regarding the risks or socioeconomic disadvantage. On rare occasions, infections may happen despite constant medication adherence; either due to drug-resistant strain involvement or simply because PrEP cannot guarantee absolute protection. In case of a confirmed HIV infection, it is essential to start antiretroviral therapy and consult an HIV specialist.
Preventing Preexposure Prophylaxis for HIV Prevention
Those with HIV can receive the best benefits from PrEP (pre-exposure prophylaxis), a type of HIV medication, when all members of their healthcare team work together to ensure the patient is taking their medication consistently and following recommended prevention strategies. This team can range from doctors and nurses to pharmacists and community health workers.
The team should focus on building a trusting relationship with the patient, and should provide clear and simple explanations. Information the patient needs to understand includes the following: how to take the medication, what side effects might occur and how to manage them, the importance of taking the medication consistently, and signs that might indicate a new infection and the steps to take should they appear.
Your healthcare team can help you stick with your treatment plan by customizing the time you take your medication to fit your day-to-day routine. They can also provide or recommend reminders to keep you from missing a dose, recognize possible hurdles that might prevent you from sticking to your treatment plan, and continually remind you about the benefits of consistent treatment. If you miss a dose, your healthcare team should address it without judgment, while ensuring you understand the importance of daily dosing to maximize the medication’s effectiveness.
Methods such as telehealth check-ins, smartphone reminders, medicine delivery services, directly monitored treatment, and pill organizer boxes may help you to stick with your treatment plan. Switching to a different version or dosage routine of PrEP, such as taking it only when needed or by an injection which lasts a longer time, might also increase your adherence to the treatment plan. For those who find it difficult to afford medications, looking for extra financial support can improve adherence. For patients dealing with substance abuse, a treatment program or counseling may prove helpful. All these solutions should fit your specific need and lifestyle, and should be supportive, recognizing the challenges of sticking to a long-term treatment plan.
Using PrEP is most effective when combined with other prevention strategies, which together form a complete package. This includes regular counseling on safe sex and drug-use habits, condom use, services for safer drug usage (where legal and available), family planning services, and regular checks for other sexually transmitted infections (STIs). Patients should remember that taking antiretroviral medication doesn’t prevent other STIs or pregnancy.
