At the end of 2022, in collaboration with the Centre Hospitalier de Luxembourg (CHL) and the health inspectorate, the Laboratoire national de santé (LNS) was named a reference laboratory for HIV and viral hepatitis by the Ministry of Health. LNS is therefore one of Luxembourg’s key stakeholders in the diagnosis and monitoring of HIV infections. By sequencing the genome of the virus, it is possible to determine effective treatment for an HIV-positive person with a positive viral load in their blood, indicating that the virus is active and multiplying.

In Luxembourg, the number of people living with HIV is estimated at around 1,200. Although there is still no cure for AIDS, most infected individuals can live normally with it, thanks to appropriate and sustained treatment. Another challenge in the fight against the spread of the disease lies in the fact that a significant proportion of infected people are unaware that they are infected, and therefore can present a danger to others without knowing it. This is why it is very important to carry out screening tests and be aware of your HIV status.

Identifying resistant mutations of the virus

“In the event of virus activity, beyond serological screening, it is important to carry out an analysis of the virus genome for each infected person in order to characterise it and identify the possible presence of mutations resistant to antiretrovirals treatment.” explains Dr Sibel Berger, clinical scientist in virology at LNS. “HIV is known to mutate rapidly and develop resistance to antiviral treatments that normally prevent the virus from multiplying. If the virus becomes resistant to a particular treatment, it will no longer be effective!”

Sequencing analysis therefore makes it possible to identify these resistance mutations and, depending on the presence of certain mutations, to adapt the treatment offered to the patient. “When monitoring those who are infected, clinicians must take into account the profile of these viruses to prescribe effective treatment. The interpretation of this profile of resistance mutations is carried out after sequencing using a complex algorithm which must be updated regularly by experts.” continues Sibel Berger. To help clinicians and enable them to implement the right treatment protocol, taking into account the numerous treatments available, LNS can provide important information on the possible resistance of the virus thanks to its expertise in the field of high-speed sequencing.

Screening and treatment monitoring

This analysis of the virus genome can be requested for different cases. “With a person whose HIV status has just been diagnosed, also known as a treatment-naïve person: it is therefore a question of defining for the first time the profile of this virus in this person,” specifies Sibel Berger. “Depending on any mutations identified, we can then apply this or that treatment, the most appropriate treatment to act against the replication of the virus. In this way, we contribute to improving the quality of life of the person living with HIV.”

A sequencing analysis may also be requested in the event of treatment failure. “If the treatment is no longer effective, this may mean that the virus has mutated and developed resistance to the antivirals on offer. If there is resistance to this treatment, the resistant variant continues to replicate. We must therefore research what these resistance mutations are and then review the treatment offered to this person,” continues Sibel Berger. Although we can live with the virus, antivirals make the viral load undetectable in more than 90% of people treated. It is important to maintain the treatment continuously, to respect it rigorously and not to stop it. “At present, there is no cure for HIV infection. The treatment must therefore be respected and the presence of the virus in the blood must be checked regularly. It is most often when treatment is interrupted that the virus multiplies, manages to mutate and risks developing resistance.” adds the clinical scientist.

A virus that is still very present

The fight against the spread of HIV is also still relevant. The virus continues to spread, in particular because some of those infected do not know that they are infected. This is why it is important to continue to raise awareness among the population, to carry out screening and to invite everyone to protect themselves and to remain vigilant after any risky behaviour. “The risk of transmission is greater when we are not aware of the danger,” explains Sibel Berger. “Prevention is therefore essential and involves above all measures preventing the transmission of the virus such as the use of condoms, or even single-use injectable equipment. There are also treatments, preventative medicine, either pre-exposure treatment, PrEP – prescribed by a doctor for certain people at risk of contamination or post-exposure treatment, TPE – antiretrovirals to be taken urgently within 48 hours after the risk of exposure.”

Currently, there is no vaccine against the AIDS virus or treatment leading to complete remission. It is therefore important to continue to raise awareness, prevent, screen and treat.