VaccinesProducing vaccines without the use of chemicals

Published 16 January 2019

Producing vaccines is a tricky task – especially in the case of inactivated vaccines, in which pathogens must be killed without altering their structure. Until now, this task has generally involved the use of toxic chemicals. Now, however, an innovative new technology developed by Fraunhofer researchers – the first solution of its kind – will use electron beams to produce inactivated vaccines quickly, reproducibly and without the use of chemicals.

Vaccinations against polio, diphtheria, whooping cough and tetanus have been on the list of standard infant vaccinations for decades now. Many vaccines are inactivated vaccines - that is to say, the pathogens they contain have been killed so that they can no longer harm the patient. Despite this, the vaccine provokes an immune response: The body detects a foreign intruder and begins to produce antibodies to ward off infection.

To produce these vaccines, pathogens are cultivated in large quantities and then killed using toxic chemicals. The most common of these is formaldehyde - heavily diluted so it doesn’t harm the patient when the vaccination is administered. Nevertheless, there are downsides to even this minimal concentration: The toxin must remain in contact with the pathogen for days or even weeks to take effect, which has a negative impact both on the structure of the pathogen and the reproducibility of the vaccine. And in cases that call for speed – flu vaccines for instance – drug manufacturers are obliged to use higher dosages of formaldehyde. The product must then undergo a time-consuming process of filtration to avoid traces of the toxic chemical being left behind in the vaccine.

Electron beams kill harmful pathogens
Fraunhofer says that now, pharmaceutical companies will be able to produce inactivated vaccines without the slightest trace of toxic chemicals – quickly and reproducibly. The scientists who developed this process see its greatest potential in the production of vaccines that until now were not amenable to the method of chemical inactivation. The technique was developed jointly by researchers at the Fraunhofer Institutes for Cell Therapy and Immunology IZI, Manufacturing Engineering and Automation IPA, Organic Electronics, Electron Beam and Plasma Technology FEP and Interfacial Engineering and Biotechnology IGB. “Instead of using chemicals to inactivate the pathogens, we employ low-energy electron beams,” explains Fraunhofer IPA team leader Martin Thoma. The accelerated electrons break down the DNA of the pathogens either via direct collisions or through the generation of secondary electrons, which subsequently result in single or double strand breaks. In a nutshell, the electrons fragment the pathogens’ DNA while maintaining their external structure. This is important to trigger an effective immune response.

The challenge arises from the fact that the electrons cannot penetrate very deeply