"The diagnosis of proximity is the hope for better management of hepatitis C"

How to make diagnostic tests for hepatitis C more accessible in Africa? This is the challenge of "decentralized" screening tools, carried out close to places of life and not only in large cities, which force potential patients to long and expensive journeys.

Follow our series
        
    
          Hepatitis C, the big forgotten
          

Professor Karine Lacombe, infectiologist at Saint-Antoine Hospital (Paris), conducted modeling with her team on the impact of the deployment of these tools in Cameroon, Côte d'Ivoire and Senegal. open up the prospect of better care for infected patients. Interview

Who are the people in Africa affected by hepatitis C.

Karine Lacombe Hepatitis C affects up to 19 million people in Africa. But its frequency is very heterogeneous according to regions and populations. New infections in Africa concern well-identified risk groups: injecting drug users. Hepatitis C virus (HCV) is spread through blood via needles or medical devices that are contaminated due to deficiencies in the care systems. "Silent" for many years, the virus reaches the liver cells, leading, for the most serious complications, to cirrhosis or cancer of the liver.

Episode 1
        
    
          "In Nairobi, the heroin addicts in my squat had never heard of hepatitis C"
          

In some megacities, the spread of injection drug use is a big emerging issue. East Africa is the most affected, especially in Mombasa (Kenya) and Dar es Salaam (Tanzania). West Africa is a little less, because the drugs are mostly smoked or sniffed. But there are notable exceptions like Dakar (Senegal), Lagos (Nigeria), Abidjan (Ivory Coast). In Dakar, up to 25% of drug users are infected with the hepatitis C virus.

Access to diagnostic tests is a major problem on the continent …

Indeed. In Africa, diagnostic tests for hepatitis C are mostly the responsibility of the patient. This is a considerable drag. Especially since the current diagnosis is based on two successive tests. First of all, we look for anti-HCV antibodies in the blood of patients: it is the sign of a first contact with the virus. Then, if this test is positive, one must demonstrate the persistence of the infection by molecular biology.

The search for antibodies can deliver fast results and its cost is reasonable: less than 5 euros. But the second test, longer, is also more expensive: it can cost up to 75 euros on the continent. And it requires significant human resources and large machines that serve to amplify the genes of the virus, difficult to use in the field. It can not therefore be proposed in mass screening.

How to facilitate access to diagnosis?

The major challenge lies in the deployment of decentralized tests, "at the bedside", capable of delivering a quick result at an affordable cost. Because the current "centralization" of tests poses two major problems: it limits access to diagnosis and treatment. To get tested, patients have to go to a big city: many will not go for lack of money and they will escape the diagnosis. In addition, there will be "lost sight": among the people who will go to be tested, some will not return the trip to come and get their results. In case of proven infection, they will not get treatment.

Episode 2
        
    
          In Cameroon, diagnosis and treatment of hepatitis C are still reserved "to an elite"
          

Faced with these challenges, new strategies are being studied. Technical progress is here to welcome. Antibody detection can already be done by a quick test. Then, it can be supplemented "in bed of the patient" thanks to the tests using GeneXpert and GeneDrive technologies, in particular. The cost of GeneXpert is around 17 euros per test. These new tests can also be performed in a single step, without going through the detection of antibodies.

These new diagnostic tools can they be generalized?

Their interest today is to study in some African countries. In Cameroon, Côte d'Ivoire and Senegal, our team conducted modeling work on the impact of their deployment in the field. Verdict: they become interesting from a certain frequency threshold, when the infection affects at least 44% of the population. That is to say, among the drug users, for the most part. But also, in the north of Cameroon, in the over 50 years infected in the 1960s by vaccination campaigns. Apart from these risk groups, the two-step strategy is preferable.

Episode 3
        
    
          How Morocco became a producer of a generic against hepatitis C … which remains inaccessible
          

These tools are not yet widely used in Africa. GeneDrive has just completed its validation studies. GeneXpert uses a machine already deployed in the field to screen for TB and HIV. To adapt to hepatitis C, simply buy the "cassettes" of screening corresponding to this infection. In the North, the deployment of GeneXpert's use for hepatitis C began only a few months ago. These diagnoses of "proximity" are the hope of a better management of the disease on the continent.

In Cameroon, Senegal and Côte d'Ivoire, you have quantified the impact of a broad access to treatment of hepatitis C …

If we screened and treated all infected people, through a decentralized screening in one or two stages, we could avoid 2 100 liver cancers per year in Senegal, 1 700 in Ivory Coast and 2,000 in Cameroon

This work, funded by the ANRS, was conducted from 2015 to 2017 on 120 patients infected with HCV. One third of them were also infected with HIV. We showed two things. First, treatments for hepatitis C are effective in 90% of these patients, both monoinfected and coinfected. Second, broad access to hepatitis C treatment divides by three the number of patients with cirrhosis and by 6.5 the number of patients with terminal liver disease.

The HCV coinfections and are HIV prevalent on the continent?

No. HIV in Africa is mostly sexually transmitted. HCV is transmitted through drug use or poor health care systems. At-risk groups are not necessarily superimposed.

Nevertheless, in the case of co-infection, it must be taken into account that, if HIV infection is not treated, it accelerates the progression of hepatitis. C to serious complications. This, all the more quickly as the patient has weakened immune defenses. However, in Africa, a large number of patients living with HIV are being treated late. In less than ten years, a co-infected patient can report cirrhosis or liver cancer

This series was conducted in partnership with Unitaid