Given the spread of the new corona virus, it seems questionable whether the epidemic can be stopped soon. A vaccine would be all the more important. In mid-February, 400 experts at a conference in Geneva agreed to speed up the search for it, according to the head of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus. Vaccine development is ongoing in many countries. But how quickly could it be ready for use?
“Overall, I am very sure that we will see the first experimental vaccines this year,” says virologist Gerd Sutter from the Ludwig Maximilians University in Munich. Whether and when they could be tested on humans is another matter. “Developing a vaccine is a tedious, tedious process, especially the approval and clinical testing of a candidate.”
The development of vaccines is generally estimated to take around 15 years. A vaccine for the Mers virus, which was discovered on the Arabian Peninsula in 2012 and is also a corona virus, has only been clinically tested since 2018.
Genetic information is sufficient for vaccine production
Nevertheless, research teams worldwide announce that they want to develop a vaccine against the Sars-CoV-2 virus. Above all, they rely on biotechnological processes – they should shorten the time to prepare a vaccine candidate for testing in clinical studies. The viruses themselves are not required to produce a vaccine, as is usual, but only their genetic information. The sequence of the new virus has been known for weeks.
It contains all the information needed for its multiplication – also for the production of those components to which the body reacts after vaccination with the formation of antibodies and other antibodies. With corona viruses, this is a protein of the virus envelope, explains Sutter. “The virus uses the protein to penetrate human cells.”
The vaccine developers are concentrating on this protein. In China, Tonji University’s Shanghai hospital is working with Stermirna Therapeutics on an mRNA vaccine, the official Xinhua news agency reported. The biopharmaceutical company CureVac with its headquarters in Tübingen also relies on mRNA.
This molecule in cells mediates the conversion of the information contained in the genome into a protein. The CureVac scientists pack the building instructions for the envelope protein of Sars-CoV-2 into nanoparticles, which deliver the mRNA into the cells. The cells then form the coat protein and present it on their surface, whereupon the immune system is mobilized.
“The process mimics a concept of nature,” explains Mariola Fotin-Mleczek of the CureVac board. “We achieve a very strong activation of the immune system.”
In cooperation with the team around Sutter, a group led by virologist Stephan Becker from the University of Marburg is also working on a vaccine. As a transporter for the coat protein, they use a virus that does not make people sick. It invades cells after vaccination and forms the coat protein that is recognized by the immune system. The construction of the vaccine virus and the first production steps are expected to be completed by the end of March, explains Becker.
Sutter and Becker are among the developers of the Mers Coronavirus vaccine. They want to adapt the concept developed for this to the new corona virus. In addition to saving time, an advantage of biotechnological processes is that once a concept has been established, it can be quickly adapted to new pathogens. Only the building instructions for the protein to which the body reacts need to be replaced.
Vaccine testing takes up time
However, the development of a vaccine candidate is only the first step in the direction of the vaccine – it gets really tedious afterwards: approval and clinical testing of the candidate are the development phases that devour the most time. “If there is a candidate, you use the animal model to check whether antibodies are formed at all and whether they inhibit the virus,” explains Becker. The next step would be to check whether animals can be protected against infection with the active ingredient, then the vaccine would be produced on a large scale and tested toxicologically. “If all goes well, you can apply for a clinical trial.”
A procedure necessary for Becker. “These vaccines have to be safe, otherwise you won’t do yourself a favor.” If the political or medical pressure was high enough, the approval process would be accelerated. During the Ebola outbreak in West Africa, for example, the permission for the clinical study was granted very quickly by the responsible Paul Ehrlich Institute.
Becker is optimistic that a candidate against Sars-CoV-2 will get approval for a clinical trial relatively quickly – precisely because the platform used has already been established in connection with the Mers vaccine.
But can a vaccine be ready in time to influence the course of the current epidemic? “We don’t know how the epidemic develops,” says Becker. If the virus established itself, a vaccine would be very helpful. “I think that’s money well spent.”
WHO chief scientist Soumya Swaminathan believes that first vaccine tests on humans could begin in three to four months. A certified vaccine for widespread use will probably only be available in 18 months.