Green vaccine will cost 10 to 50 times less than conventional vaccines, says researcher Dr. Sergio Rosales Mendoza

Publicação: 12 de September de 2018

Traditional vaccines are obtained with expensive methods that involve cultivation and sophisticated infrastructure

The goal is to develop stable green vaccines that do not require refrigeration, ensuring their availability in poor countries

In a collaborative project, experts work on the feasibility of “green vaccines”, which are obtained in plant cells modified by genetic engineering techniques. In this way plant cell produce a specific protein of an infectious agent, making it able to induce after ingestion, an immune response to defend the body from an illness. The idea was conceived in the United States in the 1990s, adopted by various research groups around the world. “Doctors Ruy Curtis and Guy Cardineau patented this technology, opening the door to the development of attractive vaccines in benefit of global health”, said lead researcher Dr. Sergio Rosales Mendoza.

The production of green vaccines requires (i) applying immunology to choose a protein (immunogen) able to activate the immune system when orally administered; (ii) performing genetic engineering approaches to develop plant cells that produce the vaccine; and (iii) following pharmaceutical technology processes to produce the plant material under good manufacturing practices to obtain a product that complies with the sanitary regulations. “The goal is to develop green stable vaccines that do not require refrigeration, thus ensuring proper vaccination coverage in poor countries,” he added.

Different groups around the world are developing platforms for the production of green vaccines under good manufacturing practices. Currently, companies in the United States, Canada, Germany, United Kingdom and Israel are developing and refining the platforms to produce this type of vaccines on a large scale. “In Mexico, basic research is carried out, focusing on creating the proof of concept to furtherly build alliances with industrial partners interested in adopting these technologies,” says the researcher when stating that large-scale production will still take some time. It is expected that in a period of 10 years approval processes could be finished, to obtain authorization for human use of the vaccines. According to him, in Canada and the U.S., there are companies producing and evaluating green vaccines against influenza, which could be the first to be marketed as injectable formulations.

Regarding the resistance of traditional pharmaceutical market, Dr. Rosales believes that this expected since the industry tends to follow conventional systems. “Having this in sight, it is necessary to look for alternatives to achieve the exploitation of green vaccines, for instance non-profit organizations in partnership with universities and public research institutes could render alliances to achieve the production and use of these vaccines in the benefit of the health sector,” he said. For him, it will be especially necessary in the case of vaccines against diseases that do not represent an attractive investment for industry, for example, those affecting only developing countries. Remarkably, it is estimated that green vaccines will cost less than the traditional vaccine. According to Dr. Rosales, a green vaccine will cost 10 to 50 times less than the conventional ones, due to the low cost materials involved in production and the relatively simple infrastructure needed during production, distribution, and delivery.

Dr. Rosales, who is a professor at the Universidad Autonoma de San Luis Potosí (UASLP), bets on the exclusive benefits that green vaccines provide, among them: they have very low production costs since the plant material is obtained with a simpler infrastructure than the once used by conventional technologies; green vaccines would not require refrigeration for storage and distribution, since they are produced in the form of tablets or capsules that are stable at room temperature. Additionally, green vaccines could be administered orally, then the use of sterile syringes and the need for trained personnel to inject people are avoided. Another advantage relies on the high security that plants offer as host for vaccine production due to the fact that plants do not replicate infectious agents for humans or contain toxins, compared to some traditional systems in which contamination with endotoxins, virus or prions could occur. “On the other hand, these vaccines do not contain whole pathogens, which in the case of some conventional vaccines confer the risk of developing the infection”, he adds.

How does the extraction happen

The plant producing the vaccines is processed to have their tissues dried. The idea is that the capsules or tablets containing the dried plant material are prepared and, when ingested, they release the protein (antigen) that will be detected by the intestinal immune system with a subsequent induction of protective immune responses. “Another alternative is to purify the antigen and create injectable formulations, however this increases the cost of the vaccine because the purification process is expensive and requires sterile syringes and trained staff for its administration”, justifies.

Side effects

Dr. Rosales remembers that all medications are carefully assessed regarding safety before being authorized for human use, in order to minimize the adverse effects likely to occur among the population. Some vaccines formulated with attenuated viruses have the risk of developing side effects (infection), however, the frequency is very low. “In the case of green vaccines, no whole microorganisms are present in the formulation as it contains plant material only, so the risks associated with these organisms are eliminated. However, green vaccines must be validated in their safety at different levels, which is underway”, he emphasizes.

Asked if allergic people could benefit from green vaccines, he elucidates that the limitation would be for patients allergic to the plant used to produce the vaccine.

Could green vaccines bring a new acceptance concept by anti-vaccine movements?

To the expert, the main struggle against anti-vaccine movements should be based on knowledge dissemination, so the user will be able to have an assertive vision of the technologies being able to understand their foundations, as well as the risks and their great benefits for the population. “Green vaccines provide a number of advantages that could make them a widely accepted technology in society, as they do not containing chemical preservatives, viruses or bacteria that carry the risk of developing an infection”, he concludes.