April 30, 2018, by Editor
New approach to HIV prevention
This blog has been written by Carlos Sanders-Velez, who is working in the School of Pharmacy with Dr Pavel Gershkovich.
Despite advances in diagnosis and treatment, HIV infections are still a worldwide issue. Currently 37 million individuals are living with HIV, with nearly 2 million new diagnoses in 2016 (UNAIDS, 2017). While treatment currently exists and is effective in most cases, all of the antiviral agents have severe side effects.
To tackle this the School of Pharmacy has embarked on a research project to develop an alternative form of PEP (post-exposure prophylaxis) which would be administered locally into the rectum or vagina after potentially unsafe intercourse.
In order to develop the treatment the team first need to understand people’s sexual habits, in particular regarding the use of condoms and have developed a short survey https://nottingham.onlinesurveys.ac.uk/sexual-health-and-hiv-prevention-english
Carlos Sanders-Velez is undertaking the study and says; “We believe that if we design a novel “virus-like” drug delivery system which could be administered rectally or vaginally, within a 3 day time frame we would be able to prevent HIV infection. Due to the unusual delivery, we have developed a social survey to understand interest for our approach. The purpose of the survey is to identify and demonstrate the frequency of the situations of accidental unsafe rectal or vaginal sex.”
Most preventive HIV campaigns are based on a safe sex practice (i.e. the use of condoms during intercourse), despite this unprotected sex with an HIV positive individual is the main transmission route for HIV.
Current preventative approaches
Besides safe sex, other preventive approaches exist, all of them based on drug-based schemes: Treatment as Prevention (TasP), pre exposure prophylaxis (PrEP) and post exposure prophylaxis (PEP). TasP is based on the principle of treating existing HIV cases, so that they can’t pass on the virus. PrEP and PEP are based on the prescription of antivirals to healthy people, however there are big differences between them.
- PrEP (Pre-exposure prophylaxis): this is based on low-dose oral tablets of antiretroviral drugs which are to be taken every day by people who are sexually active, and are in a high risk group of acquiring HIV (Ozdener et al, 2017).
- PEP (post-exposure prophylaxis): This is currently only used in very high risk cases, usually after confirming HIV positivity of the source. It involves a full month of daily treatment (with oral tablets) using a very high dose of anti-HIV drugs, with a lot of serious adverse effects (Cresswell et al, 2016).
The rationale for this new approach is based on the fact that following rectal or vaginal exposure to the virus, it takes several days (up to 7 days in some cases) for the virus to enter the blood stream (Murray et al, 2011).
The main target population for this preventative measure are people who usually do use condoms, but for one reason or another had an event of unsafe sex (such as condom failure, no condom available and still proceeding with intercourse, pressure from partner to have unsafe sex and so on). Our approach would then provide an option to people who found themselves in such situations to go to a health-care professional, to obtain prescription to this rectal (or vaginal) preparation, to administer it up to few days after the incident, and prevent serum conversion.
If you have five minutes to spare to answer ten questions regarding this subject, it would be much appreciated.