Doc, how effective is PEP and is sex safe while on the pills?

Dear doc,
How effective is HIV prevention by PEP? When should you start taking PEP? When am I supposed to test again after PEP? Can I have intercourse while on PEP?
Sm

Dear SM,
PEP is post-exposure prophylaxis, which in the context of HIV means taking ARVS after being exposed to HIV so as to prevent acquiring the virus. PEP is considered if you have been exposed to highly infectious material like blood, semen, vaginal secretions, breast milk or bloody body fluids and these fluids have come into contact with broken skin, a mucus membrane (mouth, eyes, nose, gastrointestinal tract, respiratory tract, urinary tract, reproductive tract) or you have been exposed through a cut or injection. The exposure may be from a known HIV positive person or someone whose HIV status you are not sure about.
The first step after exposure is to do a HIV test, and if you test negative start on ARVS for prevention (PEP) as soon as possible, within 72 hours of exposure. The ARVs are taken daily for 28 days. Before starting PEP, you may have additional tests done to check for other infections like Hepatitis B and C, and tests to check the kidney function, liver function, blood level, sugar levels, but these are not mandatory. The ARVs used for PEP are the same ones used for treating HIV, though in this case you only take them for 28 days for the purpose of prevention.
Use of one drug (Zidovudine) for PEP after exposure through injection in health workers was found to reduce transmission of HIV by 81 per cent. The current medication being used for PEP is a 3-drug regimen, so the effectiveness should be much higher than that. 
The effectiveness of PEP is highest if taken within two hours of exposure, and the ARVs are still quite effective if taken within 72 hours of exposure. Once you start on PEP, you will test again for HIV after one month, then again after three months.
While taking PEP, it is advisable to use a condom during intercourse until you have had the confirmatory HIV tests. This is just in case you have already contracted the virus and can potentially spread the infection. It is also advisable to protect yourself from further exposure.

Hello doctor,
There are HIV test kits that are sold in chemists for 500 bob, and that use saliva for testing? I thought HIV cannot be spread through saliva, so how do they work?
Mali

Dear Mali,
Currently, there are two kinds of HIV self-test kits —  one that uses blood and one that uses oral fluid. The oral self-test kit is available for sale in some chemists and is available for free in government health facilities and comprehensive care clinics. The test kits come with a set of instructions on how to do the test and how to interpret the results.
For the oral self-test kit, you use an absorbent stick to collect oral fluid by swabbing the upper and lower gum, then you place the stick in the provided solution and read the results after 20 minutes. This test checks for the presence of HIV antibodies in the gum exudate, not saliva. This is an antibody test, which means you can have a negative test if you are still in the window period after HIV infection before your body develops antibodies. In case you test positive, please go to a health care facility to conform the results before starting on treatment.

Dear doc,
Please elaborate on pre-exposure prophylaxis (PrEP).
Aisha

Dear Aisha,
For HIV negative individuals who have a significant ongoing risk of HIV infection, pre-exposure prophylaxis is given. These are daily ARVs given to prevent infection, and they are taken for the entire duration that a person is exposed, whether it is a few weeks or several years. A screening assessment can be done by your health care provider or at the point of HIV testing so that you know whether you qualify for PrEP or not. PrEP does not completely eliminate the risk of HIV infection, but it reduces it if used properly, and it does not prevent STIs or unintended pregnancies.
You qualify for PrEP if you fit any of the following descriptions:
Sexual partner is known HIV positive and is either not taking medication, or has been on medication for less than six months or is suspected or confirmed to not be taking their medication well. 
You have one or multiple sexual partners of unknown HIV status and are at high-risk for HIV infection because your partner has multiple sexual partners, has had STIs, engages in transactional sex, injects drugs, or men who have sex with men  
engaging in transactional sex. History of recent sexually transmitted infection, repeated use of post-exposure prophylaxis. History of sex whilst under the influence of alcohol or recreational drugs as a habit. Inconsistent or no condom use or unable to negotiate condom use during intercourse with persons of unknown HIV status . Injection drug use where needles and syringes are shared.  
Sero-discordant (One partner is HIV positive and the other one is HIV negative) couples trying to conceive.
For someone to start on PrEP, they have to test HIV negative before initiation, and should not have any symptoms of acute HIV infection (fever, sore throat, muscle or joint pains, swollen glands, diarrhoea or headache) following a recent high risk HIV exposure. The person will test for HIV every three months until the risk status changes.
If you start PrEP, you should take it every day, and only stop in case of the following:
Person becomes HIV positive 
The risk of acquiring HIV changes from high to low status
Kidney dysfunction.
Sustained poor compliance with treatment.
The HIV positive partner in a discordant relationship achieves confirmed undetectable viral load.
Person requests to stop
To stop the PrEP, you should continue taking the ARVs for 28 days since the last HIV exposure.

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