FAQs
Overview
PrEPVacc is an African-led, European-supported HIV prevention project running in four countries in East and Southern Africa from 2018 to 2024. For the first time, it is combining evaluation of HIV vaccines and pre-exposure prophylaxis (PrEP) at the same time.
PrEPVacc has enrolled 1,513 participants in four countries. It will test whether two experimental combination vaccine regimens can provide any protection against HIV in populations at risk of acquiring HIV. This is the first HIV vaccine efficacy trial to be funded outside the US.
PrEP is a proven intervention that has been shown to prevent HIV, where an Anti-Retroviral pill is taken prior to being exposed to HIV. PrEP will be given in the trial during the time that participants are expected to reach their peak immune system response from the vaccines (three vaccination timepoints over six months). During this time, the trial will also assess a new PrEP agent against the established standard for PrEP.
The project name PrEPVacc is a conjunction of the two preventive methods: PrEP and Vaccines.
The PrEPVacc project dates are from January 2018 to December 2024. The preparation for the trial includes a Registration Cohort (observational study), whose first participants were enrolled in July 2018.
The first participants in the clinical trial enrolled in December 2020 and the last enrolled in March 2023. The study is no longer enrolling participants. The immunisation schedule will last 48 weeks, the PrEP schedule will run in the first 26 weeks, and all subjects will be followed up for at least 26 weeks after the immunisation schedule ends.
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In December 2023, the study announced that it had stopped further vaccinations as there is little or no chance of the trial demonstrating vaccine efficacy in preventing HIV acquisition.
The full results of the vaccine trial will not be known until all the study visits have been completed, which the study teams aim to do by June 2024. Full results will be analysed and shared with participants, study teams and the public in the second half of 2024.
The oral PrEP component of the study is continuing to completion.
A vaccine teaches the body’s immune system to prevent a particular infection or fight a disease, to keep you healthy. The world does not yet have a licensed vaccine to prevent HIV. In order to develop an HIV vaccine, researchers need to test it in people, to find out if it might help prevent or fight HIV. It is given as an injection.
Goals
For the vaccines, it will either rule out or encourage further development of two different combination vaccine regimens for preventing HIV. Both these regimens have already been tested in clinical trials and have demonstrated their safety.
At the same time it is testing whether a new form of oral PrEP, TAF/FTC (Descovy), is equivalent or more effective than the existing standard TDF/FTC (Truvada) taken daily, in the context of the current PrEP availability situation at the study sites. Participants will be offered PrEP during the vaccine immunisation phase (6 months) in order to prevent HIV. PrEPVacc will gather data on social acceptance and attitudes to PrEP, its uptake, safety and adherence in at risk populations that are expected to benefit from PrEP.
It is a pioneering time for HIV vaccine development with two combination regimens being tested in large scale trials in Africa (the now stopped HVTN 705 'Imbokodo' and HVTN 702 ‘Uhambo’).
PrEPVacc is complementary to these two other efficacy trials as it is evaluating a combination of different vaccine candidates and regimens. The two regimens to be trialled in PrEPVacc -- one combining DNA with protein based vaccine, and the other combining DNA, MVA and protein based vaccine -- have already been evaluated in multiple phase I/II clinical trials in US, Europe and Africa and have demonstrated their safety and ability to induce immune responses. Some participants will receive a placebo that does not contain vaccine, which will be a sterile liquid called saline. The outcome of PrEPVacc will tell us whether developing either of the two different combination vaccine regimens for preventing HIV is worthwhile or not.
The PrEP results will say whether a new form of PrEP is as acceptable, safe, and effective as the available oral standard PrEP, in women as well as men. This will be valuable for informing future implementation and uptake strategies by local stakeholders in settings where PrEP uptake is low even when accessible, but is likely to be more widely available in the future.
The countries taking part in PrEPVacc are all committed to reducing and ultimately stopping all new HIV infections and a successful HIV vaccine would be a critically important preventive method.
Study Design
PrEP provides close to perfect protection against HIV when taken consistently during periods of risk. Participants in the trial will be given PrEP during the period they are receiving vaccinations, in order to prevent HIV. This is to give the vaccines the best possible chance of working. When assessing a vaccine’s efficacy, the trial will only count HIV infections that happen after the primary immunisation schedule is complete (comprising three vaccines over six months). Enrolled participants are not obliged to take PrEP, but the trial will encourage them to use it as an HIV prevention option, and researchers will try to find out what the barriers to acceptance are among those that decline it.
A placebo is not a vaccine. It is a neutral substance with no active chemical ingredients. In most clinical trial settings, the differences observed between the placebo and test vaccine groups enable researchers to evaluate whether the test vaccine is safe, and whether it works or not.
Participation
As of March 2023, the study has completed enrolment and is no longer enrolling participants. See our Joining the study page for further details including the participation criteria.
We will always give study participants full information about the study before they join, so they can give us informed consent to take part.
Participants have the right to leave the study at any time.
During the study, the clinic staff will monitor participants to make sure the vaccines and PrEP are not causing any health problems.
The clinic staff will also assist participants who report any social problems they may experience from being in the study.
Participant safety is managed by a study safety review team and an independent safety monitoring board that regularly look at the health information from the study participants to decide whether it is safe to continue giving the vaccines and PrEP.
An institutional Ethics Committee reviews and monitors the study plan for each site doing the study, including the information that is given to people about the study, study progress, and health problems in participants. The Ethics Committee also looks at whether participants’ rights are being respected.
Each study clinic has a Community Advisory Board. Its members are local people who advise the researchers and bring the concerns and interests of the community and study participants to the researchers.
Locations
The study is running the vaccine trial at four sites in three countries: in Masaka, Uganda; Mbeya, Tanzania; Dar-es-Salaam, Tanzania and Durban, South Africa. The study enrolled 1,513 men and women aged 18-40 years from the general and key populations who report behaviours that put them at increased risk of catching HIV. This may include female bar workers, people living and working around main highways, commercial sex workers, fisherfolk and men who have sex with men.
The Maputo, Mozambique site is part of the Registration Cohort but not the clinical trial.
A key part of the PrEPVacc project and the way it is organised is to grow the capacity of African sites to do future trials themselves and to foster future leaders. PrEPVacc is led by African researchers who oversee the trial database, trial management, and primary laboratory assays. PrEPVacc’s project leadership is located in Entebbe in the MRC/Uganda Virus Research Institute. MRC/UVRI has managed multi-centre trials before in Uganda; this is its first multi-country trial. All of the African centres have taken part in HIV vaccine trials before, but not all have conducted phase III trials at significant scale, so PrEPVacc will give new experience to hundreds of staff, and support knowledge exchange between centres with experience and those without.
PrEPVacc is supported by European and American partners, and funded by EDCTP with support from USAID, UKRI and the Bill and Melinda Gates Foundation.
PrEP
PrEP is the use of antiviral drugs by HIV-negative individuals to reduce their risk of HIV infection. The only PrEP available in 2019 is a combination of two drugs in one pill. PrEP is taken as a tablet, and it is best to do so with food in your stomach. In most countries you need to go to a health care facility to get PrEP, and PrEP may or may not be free.
No drug is 100% safe but very few people have had to stop taking PrEP due to side-effects. The most common side effects are upset tummy, diarrhoea and headache. These are most marked in the first few days of taking PrEP but usually settle down quickly. Taking PrEP with food in your stomach helps, and it’s also worth changing the time of day that you take PrEP from morning to night time, or the other way round.
Vaccine
During each of the four vaccination visits, participants will receive two injections: one in the right arm and the other in the left arm. Participants will be observed for up to one hour after the injections.
No. It is absolutely NOT POSSIBLE to get HIV infections from the vaccines used in this study. The vaccines do not contain any live HIV, killed HIV, parts taken from HIV or HIV-infected cells. The vaccines are made up of safe chemical components.
We do not know yet. That is one of the questions we hope to answer by doing this study. All participants will be counseled on how to prevent HIV infection and will be encouraged to use the available prevention methods through the study.
These same study vaccines were evaluated in previous studies and we have not seen any serious health problems related to them. Each participant’s health will be watched closely throughout the study.
No, vaccines are meant to stimulate your body to build immunity against HIV. The vaccine doesn't cause barrenness in women. We ask women to use contraception through the study to prevent a pregnancy, we don't know the effects of this vaccine in a baby in development.
No. The antibodies elicited from the vaccine cannot transfer to your partner during sexual intercourse.
We do not know the exact duration but this can vary from 1 to 20 years. If you would like to know more about VISP we recommend watching this short video produced by IAVI.
Bloods
The amount of blood drawn is small, only 10ml and this can not cause any negative effects on the body. 10ml is equivalent to two teaspoons. A human body has 5 litres of blood or 5000 mls. This is 500 times the amount of blood drawn from participants for the laboratory test. The body has its own mechanisms to replace blood whenever blood is lost/withdrawn for any reason e.g blood donation or menstruation. You will not get any side effects from the blood drawn when you are hungry. We need to draw blood from a major blood vessel rather than through a finger prick to ensure that sufficient is obtained for the various laboratory tests including HIV, Syphilis, Hepatitis B and Blood collected during the screening visit will enable thorough screening and confirmation of the laboratory test.
We do HIV testing, checks on organ functions, checks to see if the study product is working and to better understand the mechanisms by which it works.
After the trial
We will refer you to local health and HIV prevention services should you require any care. You can access these testing areas immediately after the study ends. We will stay in touch with you until the study results are available to share with you. The study staff will also talk to you about how you can continue to contribute to the fight against HIV through participation in other studies, by serving on Community Advisory Boards or other community engagement structures, or doing advocacy work.
Participants will be among the very first to know the results of the trial. However until the results are fully understood and any efficacy confirmed there will be no plans to give the vaccine to participants after the study.
We expect the study to be completed by December 2024 and to learn whether the study vaccines and the new PrEP are preventing HIV infections by that time, but it is possible that we may know sooner. Whenever this information becomes available, it will be shared with the study participants and relevant stakeholders.
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In December 2023, the study announced that it had stopped further vaccinations as there is little or no chance of the trial demonstrating vaccine efficacy in preventing HIV acquisition.
The full results of the vaccine trial will not be known until all the study visits have been completed, which the study teams aim to do by June 2024. Full results will be analysed and shared with participants, study teams and the public in the second half of 2024.
The oral PrEP component of the study is continuing to completion.
Your contribution to help the researchers determine if these vaccines work for HIV prevention is appreciated.
PrEPVacc is not a licensure trial, and so if efficacy is shown, and the combination vaccine is safe, the result will need to be confirmed through a further trial or trials. New funding would be required and likely new partners to help with this. The closer we are to the target efficacy of 70%, the easier this will be and the faster we will move on to the next steps.
The team is actively considering how to confirm efficacy in open-label trials in which all participants receive an active product. This has never been done for an HIV vaccine trial, although there are examples from other disease areas such as Ebola and the HIV PrEP trials.
Efficacious vaccines must be effective for the population and country to administer once access to them is provided, and access depends on approval from the national authorities and the availability of vaccines. This means researchers working with manufacturers of vaccines and international organisations that support the global distribution of vaccines. We are fortunate to have the International AIDS Vaccine Initiative as a partner in PrEPVacc and they would be able to help mobilise these efforts.
PrEPVacc is also evaluating a new PrEP agent, Descovy. As of July 2021, Descovy is already approved for the treatment of HIV and for men to use for prevention. If PrEPVacc can show that Descovy is as good as Truvada when women use it for prevention this will help extend the approval to women. We are fortunate to have Gilead as a partner in PrEPVacc as they are responsible for the manufacture of the drug and well-positioned to facilitate this. Such a scenario is beyond the remit of PrEPVacc’s work but in such a case PrEPVacc would seek to begin discussions with its stakeholders and communities about moving forward access and availability of Descovy locally. If these were positive, it would support discussions between potential partners and again, the International AIDS Vaccine Initiative may be able to help mobilise this.
Whether new information on the trial is released following an IDMC review or as results at the end of the trial, participants will be among the very first to know it. At this time, participants will be updated on plans for future studies.
If the vaccine does not work, then participants are informed and will be followed up for safety. The researchers will continue to seek products that prevent HIV infection.
For Community Stakeholders
The sponsors, product developers together with the research teams will work with local stakeholders to discuss issues of access, cost, availability of the products if they are proven to be efficacious.
PrEPVacc’s target for vaccine efficacy is 70%. Before there is any rollout or implementation studies, additional studies will be needed which may include an ‘open label’ trial where all participants will be invited to use an efficacious product.
Participants may be given a choice of available HIV prevention methods or they may be allocated by chance. These plans will be reviewed by local regulatory groups before communicating to stakeholders and participants.
The goal of the consortium is to work locally and globally to ensure efficacious and effective drugs are made promptly available and accessible to the community contributing to the trials.
We cannot know whether either or both of the PrEPVacc vaccine regimens will prove effective. We must prepare for this as best we can to ensure a timely response to a positive result whilst keeping stakeholder expectations realistic.
We have every reason to anticipate that Descovy will be as effective as Truvada, and therefore PrEPVacc can have conversations with local stakeholders at an earlier stage in the process to build community advocacy and accelerate access following a positive result for PrEP.