Dead vaccines mostly made with toxic chemicals

Fight against infectious diseases: vaccines should now be produced without chemicals

The production of vital vaccines often uses toxic chemicals. However, German researchers have now developed a novel technology that uses electron beams instead. This method makes it possible for the first time to produce dead vaccines chemical-free, fast and reproducible.

Protection against infectious diseases

Vaccinations are a very effective remedy for various infectious diseases. But it is still a difficult task to produce vaccines. Because with the dead vaccines, the pathogens have to be killed without changing their structure. This is usually done with toxic chemicals. A novel technology from researchers at the Fraunhofer-Gesellschaft uses electron beams instead - and for the first time makes it possible to produce dead vaccines without chemicals, quickly and reproducibly.

German researchers have developed a new technology that makes it possible to produce vaccines in the future without the use of toxic chemicals. (Image: arcyto / fotolia.com)

Vaccines trigger an immune response of the body

Which vaccinations are recommended is determined in Germany by the Standing Vaccination Commission (STIKO) at the Robert Koch Institute (RKI).

Vaccination against poliomyelitis, diphtheria, whooping cough and tetanus have been part of the pediatrician's standard program for decades.

As the Fraunhofer-Gesellschaft explains in a statement, many vaccines are dead vaccines - the pathogens in them were thus killed and can therefore no longer harm the body of the patient.

Nevertheless, they trigger an immune response: The body recognizes them as foreign and starts the immune reaction by forming appropriate antibodies and protecting itself from the disease.

Remains of toxic chemicals remain in the vaccine

To produce the vaccines, the pathogens are bred in large numbers and then killed by chemicals. Most of the toxic formaldehyde is used here - heavily diluted, so that it does not harm humans later in the vaccination.

However, the low concentration also brings disadvantages: the poison usually has to act on the pathogens for several days to weeks, which has an unfavorable effect on the structure of the pathogens and on the reproducibility of vaccine production.

If things need to be done quickly, such as with the influenza vaccine, you can resort to higher doses of formaldehyde. Here, however, a complex filtration must follow. Nevertheless, residues of the toxic chemicals remain in the vaccine.

Electron beams kill pathogens

According to the Fraunhofer Institute, pharmaceutical companies will be able to produce dead vaccines in the future that contain no residues of chemicals - and that in addition, quickly and reproducibly.

Scientists are seeing particular potential in the production of vaccines that could not previously be produced by chemical inactivation.

Experts from the Fraunhofer Institutes for Cell Therapy and Immunology IZI, for Production Technology and Automation IPA, for Organic Electronics, Electron Beam and Plasma Technology FEP as well as for Interfacial Engineering and Biotechnology IGB have developed the corresponding process.

"Instead of inactivating the pathogens with chemicals, we use low-energy electron beams," explains Martin Thoma, group leader at the Fraunhofer IPA.

The accelerated electrons break down the DNA of the pathogens either via direct collisions, or else generate secondary electrons, which in turn lead to double or single-strand breaks.

The DNA of the pathogens is thus literally shredded by the electrons, while the outer structure of the pathogen remains intact. This in turn is important to trigger effective immune protection.

Techniques have been redeveloped

The challenge: The electrons do not penetrate too deeply into the suspension with the pathogens - for a homogeneous dose distribution, the liquid level should not be higher than 200 microns.

The corresponding techniques did not exist so far, they were newly developed at the Fraunhofer IPA.

The first method: A roll is continuously wetted with the pathogen suspension, irradiated and then transferred the inactivated liquid into a sterile vessel. So there are two fluid reservoirs: one with active and one with inactive pathogens - connected via the spinning pulley.

"This is a continuous process that can be scaled up excellently for the production of vaccines," explains Thoma.

The second approach is particularly suitable for smaller volumes, such as those used in research and vaccine development. Here, the solution with the pathogens is in bags, which are guided by a patented process by the electron beam.

Cooperation was the project base

Such a project requires different expertise, which optimally cover the four participating institutes. Among other things, the researchers at the Fraunhofer IZI were responsible for the cultivation of the various pathogens - for example, one for the bird and horse flu.

"In addition, after the irradiation, together with colleagues from the Fraunhofer IGB, we examined whether these were completely inactivated and thus offer effective vaccination protection," says Dr. med. Sebastian Ulbert, Head of Department at the Fraunhofer IZI and initiator of the project.

The know-how regarding electron irradiation was introduced by the scientists of Fraunhofer FEP.

They developed a system that precisely doses the low-energy electrons - after all, the genetic material of the pathogens should be reliably destroyed, but their structure must be preserved so that the human immune system can form the appropriate antibodies.

The process is already working, and not just on a laboratory scale:

"In autumn 2018, we commissioned a research and test facility at Fraunhofer IZI. With the continuous module - that is, the wetted roll - we can currently produce four liters of vaccine per hour, "says Ulbert.

This is already very close to the industrial standards: For example, for some vaccines, one million vaccine doses can be produced from 15 liters of exciter suspension. Talks with industrial partners are already in progress.

It will take at least another two to four years before the first electron beam vaccines come into clinical trials. (Ad)