The Swiss statement

The most popular questions and answers about the Swiss statement.

Frequently asked questions


What is the ‘Swiss statement’?

The Swiss statement says that HIV-positive people who have been successfully treated are no longer infectious in terms of sexual practice if:

  • They have had an undetectable viral load for six months or longer
  • They are undergoing treatment and adhere to it
  • They have no other STIs

Under these conditions, serodiscordant couples can consider whether to stop using condoms

What’s the background to the Swiss statement?

The statement was drawn up by the Eidgenössische Kommission für Aids-Fragen (EKAF). The federal commission for AIDS issues which advises the Bundesamt für Gesundheid (BAG).
BAG is similar to the Dutch Ministry of Health. EKAF is made up experts in the field including top Swiss researchers.

What are they saying in other countries?

In Germany, the Deutsche AIDS-Hilfe (DAH) has adopted a position that is very similar to the Swiss statement. DAH is an organisation similar to STI AIDS Netherlands, Schorer and Hiv Vereniging Nederland. In Italy, NGOs Lila and Onlus have adopted a similar standpoint.

The French Ministry of Health has also adopted a comparable position. A crucial difference is that the French say that the residual risk is too big, particularly with anal sex. They therefore advise using a condom in all circumstances.

The American Centers for Disease Control and Prevention (CDC) state that there is a strong link between viral load and infectiousness, but that even in the most favourable circumstances, HIV transmission cannot be excluded and therefore advise always using a condom.

What is the link between HIV transmission and viral load?

Viral load refers to the amount of HIV virus in someone’s blood. More virus in the blood means a higher chance of transmitting HIV during sex. Antiretrovirals are medications that suppress the HIV virus. They ensure that you do not get AIDS.
Under optimum conditions, antiretrovirals suppress the virus to such an extent that it can no longer be measured in the blood. This is called an undetectable viral load. Treatment does not always result in an undetectable viral load. Even with treatment, viral load can still increase again, for example if resistance occurs.
Through regular blood tests, an HIV treatment provider can determine whether the viral load is undetectable. The advantage of an undetectable viral load is that it is good for a person’s health and strongly reduces the chance of transmitting HIV.

Why is using condoms still the norm?

Most HIV infections are transmitted by people who are unaware that they are HIV-positive, in the acute stage for example.
It is estimated that in the Netherlands, 8,000 to 10,000 people do not know that they have HIV. That’s why using condoms with new and multiple partners is still the norm.

If you are being treated with HIV medication, can you have safer sex without a condom?

No. Using condoms is still the norm.

First and foremost for yourself: you can catch other STIs (sexually transmitted infections) like syphilis, gonorrhoea or hepatitis C that have far-reaching consequences.
The fact that you are undergoing treatment does not automatically mean that your viral load is undetectable.
With successful treatment of HIV infection where an undetectable viral load occurs, the chance of an HIV-positive person transmitting the virus through unprotected sex is (very) small however. But this also involves higher risks, like other STIs. HIV-positive people in a monogamous relationship can only consider whether to stop using condoms under specific circumstances and in consultation with their HIV treatment provider.

What is viral load sorting, who does it apply to and what are the specific conditions for it?

In practice, it has been observed that couples in which one partner is HIV-positive and the other is HIV-negative decide to stop using condoms based on an undetectable viral load. This is called ‘viral load sorting’. To keep the risk of HIV transmission with viral load sorting (very) small, a number of important conditions apply. Couples can therefore take this decision in consultation with the HIV treatment provider because he or she has insight into all relevant medical information. The following conditions apply:

  • There has been an undetectable viral load (less than 50 copies per millilitre of blood) for at least six months
  • The last test was no longer than half a year ago
  • The partner with HIV adheres to treatment
  • Both partners have no damage to the mucus membranes of the anus, penis and vagina, for example from a recent STI or rough sex
  • The relationship is monogamous and after the last STI test, neither partner has run the risk of a catching an STI

What exactly is a partner and when are you monogamous?

A partner or sexual partner is someone you have or have had sex with. A regular partner is a person you have had sex with more often and with whom you know you will regularly have sex in the future.
To exclude further risks with viral load sorting, you and your regular partner must both be monogamous. That means that you only have sex with each other and never with others. If you yourself are naturally monogamous, do not automatically assume that your regular partner is too. Wishful thinking does not work, proper agreements do.

Is ‘viral load sorting’ 100% safe?

No one can offer 100% certainty that HIV will not be transmitted during sex. There are a number of uncertainties:

  • If the virus is undetectable in the blood, it can still be present in measurable quantities in semen and vaginal discharge
  • Viral load can increase during the period between blood tests. Someone can have an increased viral load and be unaware of it, for example if the virus has become resistant. That’s why treatment adherence is so important. It is also important that viral load is tested every six months at least.

Too little is still known about the effect of an undetectable amount of virus in terms of anal sex. Most research to date has been based on heterosexual contact. The chance of transmitting HIV through anal sex is smaller with an undetectable viral load. But there is a question as to whether the chance is as low as with vaginal sex. Normally, the chance of contracting HIV and STIs through anal sex is higher than through vaginal sex.

Does an undetectable viral load completely exclude the chance of transmitting HIV, but is zero chance impossible because you are between two tests and do not know what’s happening?

Even with an undetectable viral load there is a theoretical chance of transmitting HIV. Undetectable does not mean that there is absolutely no virus, but less than 50 copies per millilitre.

As there is so little virus, the chance of infection is (very) small.
It is good to remember that ‘viral load determinations’ are periodic checks. Furthermore, it is the viral load in the blood that is tested, not semen or vaginal discharge.

If the result of a home HIV test is negative, is the viral load also undetectable?

No. HIV tests measure antibodies against HIV. They do not measure the amount of virus. In fact, someone who has just contracted HIV (acute infection) has not yet started producing antibodies and so a standard HIV test would show a negative result (no HIV antibodies) while at that point a great deal of HIV is circulating in the blood (high infectiousness).

How much higher is the chance of HIV transmission if someone has an undetectable viral load and has damage to the mucus membranes or has an STI?

Most studies have examined people with HIV who were undergoing treatment. With an STI, the amount of HIV in semen or vaginal discharge was five to tens time higher. When the STI was treated, that figure decreased to an average level.
An STI often involves damage to the mucus membranes, and there are inflammatory cells in semen or vaginal discharge. HIV targets these inflammatory cells (white blood cells). It is not known how much higher the chance of HIV transmission is in someone with an undetectable viral load.

With an undetectable viral load, what is the chance of transmitting HIV through vaginal or anal sex compared to oral sex? Which is safer?

Oral sex is safer than vaginal and anal sex. If the viral load is lower, the chance of transmission through oral sex is also smaller.

I have heard that PEP treatment is unnecessary if someone has an undetectable viral load. Does this mean that with an undetectable viral load, sex without a condom is 100% safe?

PEP involves weighing up the chance of contracting HIV infection by accident compared to the chance of (serious side effects) from PEP. This consideration is used to decide whether or not to recommend PEP. With an undetectable viral load, the chance of infection is small but not zero.

I understand that people (whose designated father is HIV-positive) wanting children no longer have to undergo ‘sperm washing’ to prevent HIV infection in children if they meet the conditions. Is this correct?

There remains a (very) small risk. It is advisable to discuss this with your HIV consultant or HIV treatment provider.

What is the difference between the chance of contracting HIV from vaginal sex and the chance of contracting HIV from anal sex?

In principle, the average chance of HIV transmission is higher with anal sex than with vaginal sex. But there are no average chances in fact, because there are all kinds of circumstances that both increase and decrease risk.

As a result, the chance of transmission is estimated to be five to ten times higher if another STI is present.
With an acute HIV infection and a high viral load, the chance of transmission is 100 to 1,000 times higher.
On the other hand, it has been recently established that treatment of HIV infection can reduce the chance of transmission by about 95%.

There are great many people with an asymptomatic STI (for example, they are carrying the herpes virus but seldom have a cold sore). Does this mean they have an STI or not?

STIs do not always show symptoms. This applies to bacterial STIs like chlamydia or gonorrhoea and also to viral STIs like genital herpes. Even if there are no clinical symptoms there can be a local response.

The mucus membranes can sometimes be damaged or irritated causing a local immune response involving white blood cells.
HIV invades white blood cells. This means that an increased chance of HIV transmission with an STI possibly applies to asymptomatic STI as well. It is not known how big the potentially increased risk is with undetectable viral load.

What is the position with breast-feeding by HIV-positive women with an undetectable viral load?

HIV can be transmitted to the baby through breast-feeding. That’s why HIV-positive mothers in the Netherlands are advised against breast-feeding. In poor countries, withholding breast-feeding is sometimes worse if there is a lack of clean water.

But what is the position if the mother has an undetectable viral load? There has been research into this in Africa. Depending on the research, HIV transmission through breast-feeding was shown in 0% to 3% of mothers taking medication and who had an undetectable viral load. So there is a residual risk. Unlike the HIV-negative partner in a serodiscordant couple, the baby has no say in whether to take that risk.

With the current test, undetectable viral load is usually defined as 50 copies per millilitre. If a new, more sensitive test becomes available that can measure 10 copies per millilitre, will the definition of undetectable change as well?

There are various viral load tests on the market that have different cut-off points. So ‘undetectable’ does not mean that absolutely no viral copies can be found. Until recently, most tests used had a limit of 50 copies per millilitre. Newer tests have a cut-off limit of 10 copies per millilitre. For our purposes, a viral load under 50 copies per millilitre is undetectable.

Suppose someone is monogamous, serodiscordant with a viral load of <50 copies per millilitre and also has rough sex. Is that dangerous without a condom? And if so, why?

We advise people to discuss specific situations with their own HIV internist or HIV nurse. The observation that damage to the mucus membranes involves a higher than average risk of HIV transmission, is based on the fact that damaged mucus membranes have fewer barriers and as a result, HIV transmission is easier.
Furthermore, with blood-mucus membrane contact and blood-to-blood contact there is a combined risk: of STIs (sexually transmitted infections) and blood borne diseases.
Compare for example, the higher chance of transmission of hepatitis C through rough anal sex with shared toys and fist-fucking.