What to know first
Assessing suitability, starting PrEP and safe follow-up
- Anyone who wants PrEP can ask for an assessment without having to disclose every risk factor.
- A negative HIV result is required before starting, followed by regular monitoring.
- The regimen and monitoring depend on health, kidney function, hepatitis B status and local availability.
What is PrEP?
PrEP, or Pre-Exposure Prophylaxis, is a medication used to prevent HIV infection before exposure to the virus. When taken as prescribed by a healthcare provider, PrEP can significantly reduce the risk of HIV transmission through both sexual contact and shared injection equipment.
While PrEP is highly effective in preventing HIV, it does not protect against other sexually transmitted infections (STIs) such as syphilis, gonorrhea, or herpes. For comprehensive protection, it is still important to use condoms consistently.
How Effective is PrEP?
- When taken daily as prescribed, PrEP reduces the risk of acquiring HIV through sexual contact by up to 99%.
- For people who inject drugs, PrEP lowers the risk by at least 74%.
- Skipping doses or not following medical guidance can decrease its effectiveness.
- Injectable PrEP is not currently recommended for people who inject drugs due to limited research data.
How Long Does It Take for PrEP to Become Fully Effective?
PrEP does not provide immediate protection. The medication must reach a sufficient level in the body to effectively block HIV. The time required depends on the type of exposure:
- Receptive anal sex (bottoming): PrEP must be taken daily for at least 7 days to reach full protection.
- Vaginal sex or injection drug use: PrEP must be taken consistently for at least 21 days for maximum effectiveness.
- Insertive sex (topping): There is currently no conclusive data on the exact time required for protection.
As for injectable PrEP, research is still ongoing. There is not yet a confirmed timeline for how long it takes to reach optimal protection. Therefore, to ensure maximum effectiveness, PrEP should be started before potential exposure and taken continuously as advised by your healthcare provider.
What Forms of PrEP Are Available?
PrEP options include: daily oral tablets and long-acting injectable medication. Each option is chosen with a clinician. The examples below are not a complete list or a guarantee of availability in Vietnam.
| Form | Medication Name | Details |
|---|---|---|
| Oral PrEP (Daily Tablet) | Truvada® | An oral PrEP option for adults and adolescents who meet the product’s age, weight and clinical requirements; an HIV test and assessment are needed first. |
| Oral PrEP (Daily Tablet) | Descovy® | Approved for individuals at risk through sexual activity, except for those assigned females at birth who are at risk via vaginal sex. |
| Injectable PrEP (Every 2 months) | Apretude | Cabotegravir for prevention through sexual contact. The first two doses are one month apart, then every two months; check local availability with the provider. |
How Much Does PrEP Cost?
Ask the clinic which PrEP options it provides and whether your healthcare entitlement covers the consultation, tests and medicine. Availability and charges vary by service; confirm the total cost and follow-up schedule before booking.
In Vietnam, ask a healthcare provider about current PrEP availability, eligibility and costs. Providers you can contact include:
- Public hospitals: Provincial and major city government hospitals
- Non-governmental organizations (NGOs)
- Private clinics
PrEP is a safe and effective method of HIV prevention. If you are at risk or simply want to take an extra step to protect yourself, learning more about PrEP and consulting with a healthcare provider can help determine if it is the right option for you.
What checks and follow-up do I need for PrEP?
A provider needs to establish that you do not have HIV before starting. Some oral regimens also require kidney and hepatitis B checks. Explain which medicines you take and any recent PrEP or PEP use. After starting, attend the scheduled HIV tests and refills. Contact your clinic if you stop, miss doses or miss an injection appointment, so they can plan the next step with you.
What is assessed before starting PrEP
The exact checklist depends on the PrEP option and local clinical guidance.
| Assessment | Why it matters |
|---|---|
| HIV test | Confirms HIV-negative status before preventive medication |
| Kidney function | Relevant to some oral PrEP options |
| Hepatitis B and STI screening | Guides medication, vaccination, treatment and follow-up |
| Current medicines and preferences | Helps select an option that is sustainable |