Vaccines, treatments and mass drug distribution raise great hope that tropical diseases, which affect more than one million poor people, may be eliminated

The fast development of COVID-19 vaccines has demonstrated that the response time of science to health needs has changed. This is one of the pieces of evidence highlighted by Pedro Alonso, director of the WHO Global Malaria Programme, in the dialogue held with Silvia Gold, president of Mundo Sano Foundation, at the closing session of the XX Symposium on Neglected diseases  on November 4.

“We are on the verge of a new scientific era of product development that will generate a revolution in global health. Vaccines have recovered their leading role by showing once again their capacity as useful tools against infectious diseases”, stated Alonso, after underlining the achievement of having the first malaria vaccine.

Another piece of evidence revealed by the pandemic is that local and national solutions to health problems are no longer enough. Global and regional solutions are the ones that have proved to be effective, stated Alonso, and cited the Americas as an example, where malaria has been eliminated in four countries.

Mass distribution of drugs

Campaigns to deliver mass treatment to all people at risk of NTDs. That was one of the most outstanding approaches of the previous road map that the WHO launched in 2012, and it was successful. It allowed, for instance, the increase of coverage in affected children and the reduction of morbidity due to soil-transmitted helminthiasis, a disease caused by parasites and the most prevalent NTD; it affects more than 200 million people only in the Americas, and more than 1,500 million people in the world.

However, there are still many challenges ahead. José Muñoz, physician and researcher at the Institute for Global Health (ISGlobal) and the Hospital Clínic of Barcelona, has been investigating soil-transmitted helminthiasis for several years and participates in an international consortium to stop the advance of this pathology, which does not cause high mortality but does produce considerable damage to physical and cognitive development, especially in children. During the symposium, Muñoz analysed the result of campaigns implemented by the WHO up to the present, based on the mass distribution of drugs, especially through schools.

While it is possible to reduce parasite burden and morbidity, the problem is “that those children come back to their home places, where very often they become infected again due to environmental pollution. We have often observed rapid reinfections 18 weeks after treatment. We have the challenge of including specific actions to improve water, hygiene and sanitation in mass drug distribution programs” warned Muñoz.

For this reason, the members of the STOP international consortium are focused on new strategies that go beyond a change in treatment. For example, why can’t we shift from treating basically in schools to treating the whole affected community? wondered Muñoz. And he showed some estimations that indicate the cost-effectiveness of this approach.

The miracle drug

It has been known for years by the pseudonym of “wonder drug”. Ivermectin shows promising results in several NTDs and can even be used against malaria-transmitting mosquitos. Alejandro Krolewiecki, a researcher in tropical diseases at the National University of Salta, in Argentina, and at the National Scientific and Technical Research Council (CONICET), works with Muñoz and other experts on a new combination of albendazole with ivermectin. This new combination not only will be more effective and safer than the current treatment, but will also allow us to include other types of helminthiasis that are currently not considered in mass drug distribution programs.

During the presentation of the research alliance, in which he participates, Krolewiecki highlighted that the level of ivermectin availability will be key to the success of the new strategy, proposed to the WHO, for the interruption of helminthiasis transmission that includes actions that go beyond the pharmacological treatment.

The proof of the need for this other set of actions in addition to treatment in different areas of development and public health is the situation of leprosy, a disease that refuses to disappear, although countries like Argentina managed to eliminate it as a public health problem. However, as Mirta Roses, Director Emeritus of the Pan American Health Organization (PAHO), stated at the opening of the symposium, it will be necessary to work in four pillars for its complete elimination in 2030: “Implement integrated Zero Leprosy road map in all endemic countries; scale up prevention alongside active case detection; manage the disease and prevent new complications, as well as combat stigma and ensure that human rights are respected”.

Meanwhile, the development of new drugs or new combinations and dosage regimens of existing ones can greatly facilitate the advances against those diseases that still have very low health care coverage. This is the case of Chagas disease. For this reason, Sergio Sosa-Estani, from Drugs for Neglected Diseases initiative (DNDi) presented some clinical studies implemented by the organization, in collaboration with Mundo Sano, in Argentina, in search of further evidence about the safety and efficacy of a treatment regimen that would reduce the time of administration from the current 60 days to approximately 15 days.

Advances in the fight against Chagas disease are increasingly focused on the control of mother-to-child transmission during pregnancy. For this reason, this year the Ibero-American Summit approved the Not a Single Baby with Chagas disease initiative, proposed by the governments of Argentina and Brazil. To date, eight countries have joined this initiative, but many more are expected to do so, as indicated by Martín Rivero, representative of the Ibero-American General Secretariat (SEGIB). It is a project promoted by Mundo Sano Foundation and supported by the WHO and the PAHO, the Evandro Chagas Institute from Brazil and ISGlobal.

Mother-to-child transmission can be interrupted, as shown by the results of the Regional Unit of Tropical Medicine of Murcia, a city where a large number of people from Bolivia and other Chagas endemic countries live. The team coordinated by Manuel Segovia at the Virgen de la Arrixaca University Hospital has not detected any case for more than two years. This result can be attributed to the persistent work of his colleagues and community action, as explained at the symposium.

Neither the vaccines nor the new therapeutic tools can be successful if they are not administered in more robust health systems, as Pedro Alonso explained at the closing of the event, which had 900 attendants and 20 international speakers, experts in neglected diseases.

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