Covid vaccine technology could benefit neglected diseases

The mRNA technology for vaccines was fundamental in the fight against the coronavirus, when immunizations were developed, enabled and approved for use in the population in record time – ten months -, with more than 4 billion doses administered worldwide.

The truth is that mRNA vaccines had already been studied for at least three decades. However, it was only with the Covid-19 pandemic that this platform was tested, and its level of safety and effectiveness, evaluated.

Now, scientists are investigating the same technology for other immunizers that do not yet exist in the world, as for the so-called neglected tropical diseases.

According to the WHO (World Health Organization), neglected tropical diseases (NTDs) are those with the highest incidence in poor countries, closely linked to socioeconomic inequalities and access to health care, and which affect more children and women. Examples of NTDs are: dengue, malaria, chikungunya, zika, leishmaniasis and Chagas disease, all transmitted by vectors (in these cases, insects), but some, such as the one caused by the worm popularly known as roundworm, transmitted by fruits and vegetables contaminated with the eggs.

For many of them, there is still no prevention, but adequate vector control and constant surveillance can help reduce cases.

As they affect middle- and low-income countries, NTDs are rarely studied by the pharmaceutical industries for vaccine development.

“The purchase of these immunizers will be the responsibility of governments, so pharmaceutical companies are not interested in developing them, there is no profit generated”, evaluates the biomedical and professor at the Faculty of Pharmaceutical Sciences, Irene Soares.

The main interest in investigating immunizations that may be effective against these and other diseases is of the researchers, but most studies in Brazil end up discontinued, evaluates the biomedical.

“We have the expertise, the main challenge is to advance to the stages after laboratory tests for human tests and obtain product registration”, says Soares.

Soares has been researching a vaccine against malaria for almost two decades. In his project, he investigates an immunizing agent capable of preventing the infection of the protozoan that causes malaria, responsible for the majority of cases in the country, the Plasmodium vivax.

The malaria vaccine that was recently approved by the WHO is based on another species, the P. falciparum, responsible for most cases in Africa, and should not work for Brazil. “It is up to us, Brazilian researchers, to develop a vaccine against malaria, otherwise there is no interest from pharmaceutical companies abroad in this immunizing agent.”

By using a recombinant protein technology, like some of the vaccines against Covid-19, the immunizer needs to be produced in bioreactors, while in Brazil the main means of producing vaccines is in embryonated eggs, a slower and ineffective process in this case.

“I had good results with tests in animal models, but my research has practically stopped for the last two years because I can’t produce the API [ingrediente farmacêutico ativo]”, it says.

That is why setting up a framework for scientific research and innovation is essential to guarantee autonomy, explains Ricardo Gazzinelli, a researcher at Fiocruz-Minas and professor at the Federal University of Minas Gerais (UFMG).

“One of the great challenges faced by universities is that researchers do the proof of concept, develop the platform, but the vaccine does not go ahead because they cannot produce the pilots for clinical trials, it is the so-called ‘valley of death'”, it says.

This was the case with many of the vaccines developed for Covid-19, such as the Oxford/AstraZeneca immunizer, which used the chimpanzee adenovirus vaccine platform, discovered by a research group at the University of Oxford and produced with the pharmaceutical company AstraZeneca.

Other examples, such as the mRNA vaccines themselves, were first discovered by researchers and then produced with drugmakers such as Pfizer/BioNTech and Moderna.

Today, the search for vaccines against tropical diseases has been able to advance precisely because of these partnerships between research centers and pharmaceutical platforms, which were boosted by the pandemic.

This is the case with another malaria vaccine announced this year, the first to reach efficacy of over 50% in phase 1 and 2 clinical trials, developed by the University of Burkina Faso, in Africa, in partnership with the pharmaceutical company Novavax.

Recently, a group of researchers at the Yale School of Medicine managed to produce an mRNA vaccine for tick disease (or Lyme disease, in English).

The vaccine platform does not act against the parasite itself, the bacteria Borrelia burgdorferi, but against the tick, causing an inflammation in the body that makes the animal no longer able to feed on the blood of the host —in this case, guinea pigs—, preventing the transmission of the microorganism.

Vaccines for neglected tropical diseases are expected to benefit nearly 2 billion people worldwide, according to the WHO, given the number of individuals seeking treatment for at least one type of these diseases each year.

In addition to these, mRNA technology should also boost the production of more effective seasonal flu vaccines, including formulas adapted to new strains, acting more quickly against new forms of the virus.