Q&A on PrEP in the UK and changes to the HIV PROUD study

NOTE: Please see this updated information about the PROUD results and access to PROUD in the UK.

The following Q&A was produced by i-Base about PrEP in the UK including recent changes to the PROUD study.

Participants in the study will be contacted shortly by the study team. People enrolled in PROUD can also contact their clinic if they have any questions.

PROUD banner

Banner from the PROUD study website which includes information about the study.

Questions about the changes to the PROUD study


If taken daily, Truvada provides close to 100% protection against HIV.

What is the PROUD study?

PROUD is a UK study looking at using PrEP to prevent HIV infection.

PrEP involves taking a daily pill which contains two commonly used HIV meds.

PrEP is only generally available in the UK as part of the PROUD study.

What are the aims of the PROUD study? 

PROUD was designed to look at practical question related to PrEP.

The main aims were:

  1. Whether people wanted to use PrEP;
  2. Whether they would take a daily pill over a longer period of time; and
  3. Whether taking PrEP change the risks people take for catching HIV.

This is why the NHS wanted to run a study in the UK, even when other studies have shown PrEP was effective.

Half the people in the study took PrEP from the start, and half had to wait 12 months before getting PrEP.

The PROUD study was not designed to show whether PrEP works, because the study was too small to show this.

Why did some people have to wait for a year?

Good studies usually need to compare two or more groups of people.

In this case people using PrEP were compared to people not getting PrEP. Everyone in the study was given information and advice on avoiding HIV, including free condoms.

To make the study more fair, the researchers decided that everyone should have the chance to use PrEP. Half the people in PROUD were due to use PrEP for two years and half for one year.

What changes have just been made to the study?

The PROUD study is now giving everyone in the study the option to start PrEP. This includes the people who were originally meant to wait for a year.

Why was the change made? 

The change is because PROUD was able to show PrEP was more effective than researchers expected.

Once the effectiveness became clear, it was important for everyone to be offered PrEP.

How many people will be affected by this change?

This will firstly affect 138 people who are in the deferred group in the study who have not yet started PrEP.

Indirectly, this may affect many more people. The significance of the finding makes it important for the NHS to review providing PrEP more widely. This is especially as an option for people who are at high risk of catching HIV.

Why was the result showing that PrEP works not expected?

Knowing that something works in a study can be different to knowing whether it works in practice. PROUD was planned as a small pilot study. This was thought to be too small to prove that PrEP worked.

We do not know yet why PROUD saw this early result.

It may be because people in the study were at even higher risk than was expected when the study was planned. It may also mean people using PrEP were adherent, or that people didn’t change their behaviour.

These things will only be known when the full results are presented.

How many people became infected and what was the difference between the groups?

This information is not yet available.

The important result is that the difference was enough to be significant. This means it is very likely to be a real finding and very unlikely to just be chance.

The full results need to include HIV test results from everyone in both groups at the time the study changes.

This is likely to take several months to organise and analyse. These results are expected early in 2015.

How soon can people in the study get PrEP?

This may vary depending on which hospital you visit but some clinics are already contacting people in the study.

Some formal changes may take a few weeks to organise.

Everyone in the study should be able to start PrEP by the end of November. Many people will be earlier than this.

If you are enrolled in PROUD, please contact your clinic.

What if I haven’t been to the clinic for a while or if I have missed visits?

Even if you missed several study visits, the researchers still want to hear from you. Everyone who enrolled can take up this offer.

Some people who were upset not to get PrEP have visited the clinic less often. This is not important and you are encouraged to reconnect with the study.

Who was enrolled in PROUD?

PROUD was designed to look at people at high risk of HIV.

In this case, the study enrolled 545 gay and bisexual men and trans* women.

In order to join the study, people also had to have a high individual risk of catching HIV. This included not always using condoms.

Why don’t people just use condoms?

This is a bigger question than can be  answered here but it is commonly asked.

No-one sets out to become HIV positive and most people are pretty good at using condoms most of the time.

However, many people find it difficult to use condoms every time, consistently for years.

Sometimes condoms break or slip off. Sometimes in the heat of the moment you may not have a condom. Sometimes people like sex without a condom because it feels better and they think the risk is low and they will be okay.

Some people don’t use condoms because they think they are HIV negative, when they are really HIV positive.

Other more complex reasons include the lack of confidence in asking a partner to use a condom, or not understanding the risk for HIV. Some people are in relationships where they want to use a condom but their partner takes no notice.

Whatever the reasons, HIV figures in the UK shows that other options could have an important role.

In UK data just released, 6000 people were diagnosed HIV positive last year (2013). More than half were gay men, and of these, 462 were under 24 years old.

Questions about PrEP

What is the pill used in PrEP?

PrEP usually involves two HIV drugs that are combined in one pill.

These two drugs are tenofovir and emtricitabine. The combined pill is called Truvada.

Some studies used only tenofovir and got good results, but the FTC may be important.

Is Truvada the only drug used for PrEP?

Currently, Truvada is the only drug approved as PrEP.

Other formulations are being studied, including injections and gels (lotions), but these are several years away.

Does PrEP work?

Yes. We knew this even before the PROUD study. Truvada was approved as PrEP in the US in August 2012.

This is based on taking PrEP everyday to get the best result.

How well does it work?

Taking PrEP every day is likely to be very close to 100% effective.

However, nothing can be guaranteed as 100% because it is not possible to prove that something can’t happen in the future.

This is as close as you can get though. At least one study has reported that daily PrEP is likely to reduce the risk of infection by more than 99%.

One study suggested that taking Truvada every alternate day (i.e. four doses a week) reduces the risk by more than 95%.

Why are lower rates of protection sometimes reported for PrEP?

The rates above are based on results from people who were taking PrEP.

In most PrEP studies, people who didn’t even take PrEP are included in the total results. This overall result is important to know how effective PrEP is in a population.

But for people making individual choices, the most important result is to know how effective PrEP if you take it as prescribed.

What happens if you miss a dose?

With such a high level of protection, missing an occasional dose is unlikely to make any difference.

Also, the drugs in Truvada stay in your body for long enough to cover a missed day.

However, the more often you miss a dose the more likely the protection will drop.

As with any med, you need to take Truvada for it to work.

As with any treatment, if you are having trouble remembering to take a medicine, it is important to talk to your doctor. There are lots of things you can do that can help. 

Tips on remembering to taking pills (from a resource about HIV meds). 

How quickly does PrEP work?

You probably need to take PrEP every day for at least a week before relying on protection.

This is likely to get drug levels high enough to reach more than 90% protection.

After two weeks the drug levels will be at “steady state”. This is a medical term for reaching the best stable levels.

Can I just use PrEP when I need it?

There are different aspects of this question.

Just taking PrEP when you are going to have sex is unlikely to provide much protection.

This is because the most active drug in PrEP – the tenofovir – can take 24 hours to be absorbed into some parts of your body.

Some ongoing studies are looking at alternative dosing schedules for PrEP. Until other options are proved effective, daily PrEP is recommended.

However, if your circumstances change so that your risk of HIV changes, you can talk to your doctor about stopping PrEP. If your circumstance change again in the future, you could restart PrEP again. If you do this, remember it takes a week to reach protective drug levels.

What about side effects?

Anything you put in your body has the potential to cause a side effect. With a medicine this risk is usually low in order to be approved. Also, as a prescribed medicine, your doctor with test and monitor for this.

The drugs in PrEP are some of the most commonly used HIV drugs. They are used by millions of people globally, often for many years.

These drugs can cause side effects, but the risk is generally low. It means that routine monitoring is essential just in case there are problems.

Each person still has to decide whether this risk is worth the protection against HIV. People who decide “yes”, may benefit from PrEP. People who decide “no” may prefer sticking with condoms.

Can I get PrEP if I am not in the PROUD study?

PrEP is not currently available in the UK on the NHS unless you are in the PROUD study.

A doctor can prescribe Truvada for “off-license” use if this is best for their patient, but the NHS has not yet approved PrEP or agreed to pay for it.

People with private health care may be able to access PrEP but very few people are likely to be using PrEP outside of PROUD .

Free access on the NHS will only be decided after reviewing the study results. This may also involve deciding under which circumstances PrEP is cost effective.

Further information

The website for the PROUD study include more information about the full study design, patient information and the announcement of the recent changes.

This i-Base article reports on the study changes.

This is an interesting blog from a US doctor who uses PrEP to protect his own health.

This article reports the most recent results from the iPrEX study presented at the AIDS 2014 conference in July.

This search link include many more articles relating to PrEP.