HIV PEP medication has been helping to greatly reduce the possibility of infection after exposure to HIV. PEP is prescribed for 28 days as a two or a three-drug regimen. It is recommended that PEP therapy starts within 72 hours after HIV exposure. A recently published report compared the efficacy of the 28 day full prescription of PEP versus the practice in which a 3-5 day PEP Starter Pack course is handed over to patients and they are provided with rest of the PEP course at the next visit.

The Starter Pack

PEP Starter Packs are prescribed by some instead of the whole 28-day PEP to

• help new users get used to the regimen
• facilitate and encourage adherence
• evaluate potential toxicity
• reduce anxiety for worried patients while providing counseling at the same time

About The Paper

This paper is basically a compilation of data available on PEP practices and the outcomes will help inform future World Health Organization (WHO) PEP guidelines.

Two different authors of the paper simultaneously searched online databases for articles, abstracts and conferences available on PEP practices. In case of any disagreement among the two authors a third author helped. Only randomized trials and prospective observational studies were included in the formulation of the results. The reports which did not report PEP duration and had less than 10 individuals with PEP were not included in the study.

The type of HIV exposure, the study population, the number of drugs for PEP and the use of zidovudine / tenofovir along with attendance in follow-up visits were evaluated in the study.

Results

Although the overall result quality of this systemic review were marked to be very low, the results showed that out of the total 3259 titles which were initially selected only 54 studies passed the inclusive criteria. Out of these, 37 studies were about the Starter pack while 17 studies reported results of the full 28 day PEP prescription.

According to the report, Starter packs were usually given for a period of one to 14 days. 47% of the studies done on the Starter pack showed that most were given a 3-day Starter pack.

It is interesting to note that the prescription of a full 28 day PEP was more common among occupational exposure. It was reported that 22.4% of  individuals who were started on the Starter pack PEP refused to complete treatment as compared to the 11.4% receiving full PEP. 6.8% of the subjects receiving Starter pack stopped the medication due to toxicity while failure was 4.2% in people receiving full PEP.  The overall completion rate of PEP was 70% among the people who were prescribed full PEP versus the Starter Pack which was only 53.2%.

Conclusion

In conclusion, it can be inferred that the Starter packs might have some benefits but the overall compliance and adherence is not ideal. Therefore, an early start of full 28 day PEP is recommended.

Source:

Ford N et al., Starter Packs Versus Full Prescription of Antiretroviral Drugs for Postexposure Prophylaxis: A systemic Review. Clinical Infectious Diseases, 2015.

Among occupations, Medical professionals are the ones who are most highly exposed to infections and threats of communicable diseases. Human Immunodeficiency Virus (HIV), being an untreatable virus, holds great risk to medical professionals especially those who work with HIV-infected patients and needles. HIV Post-Exposure Prophylaxis (PEP) is something that can greatly reduce the risk of infection during the course of their work. A review article published in a medical scientific journal, “Clinical Infectious Diseases” in 2004 gathered the published data to correlate the efficacy and toxicity of two drug and three-drug PEP regimen for occupational exposure to HIV.

Most of the available literature is on animal models as there are ethical limitations for clinical trials on humans. In a nutshell, these trials show an earlier start and a 4-week use of PEP is the most effective. Only one case-control study, reported and published in 1994, was conducted on health care professionals which showed that the use of a single antiretroviral drug (zidovudine) decreases the risk of HIV transmission to 79%. It also showed that only 33 out of 698 professionals, receiving monotherapy PEP became seropositive. After this study, the Center for Disease Control and Prevention (CDC) developed empirical PEP treatment guidelines for occupational HIV exposure.

These guidelines suggest the use of at least two drugs for PEP. According to the review there is more usage of a three-drug therapy in both the USA and Europe despite more side effects than a two-drug therapy which unfortunately leads to lesser compliance and early discontinuation usually resulting in PEP failure. However, HIV infected patients show better compliance to therapy with three-drug as compared to people receiving PEP for prevention.

For minor pricks and exposure to aberrations, CDC recommends the use of only a 2-drug regimen of PEP. The aim is to prevent virus from developing the infection in the body which can be achieved by a 2 drug therapy for at least 28 days. For more deep exposure like penetrating wounds, a three-drug therapy is recommended. Interestingly, one study showed that those on a three-drug PEP therapy had more side effects than HIV-infected patients on a three-drug treatment as well as an 8-times higher rate of discontinuation.

The review showed that the efficacy of the three-drug PEP was better than the two-drug PEP, but overall adherence to the treatment was better with two-drug PEP therapy. As mentioned previously, the toxicity was found to be higher with three-drug PEP. Although there is  data on the frequency and percentage of the antiretroviral drug resistance, there is almost no data on the extent of drug resistance to the different types on PEP.

Based on the available data, the authors of the publication made a model for the PEP which showed that without HIV PEP, 300 out of 100,000 HIV-exposed health care professionals will become seropositive. This transmission will come down to 108/100,000 with three-drug PEP therapy. A two-drug PEP will result in transmission to only 105, which are only 3 cases less than the three-drug PEP.

The two-drug PEP, as a whole, has better outcome and lesser toxicity than the three-drug PEP. Therefore, with lower antiretroviral resistance a two-drug PEP is recommended by the review.

Source:

Bassett I V et al Two Drugs or Three? Balancing Efficacy, Toxicity, and Resistance in Postexposure Prophylaxis for Occupational Exposure to HIV. Clinical Infectious Diseases, 2004.