The hunt for a corona vaccine: this is how vaccine research goes | NOW


According to Minister Hugo de Jonge of Public Health, we are only protected against the corona virus if there is a vaccine. looks in a mini-series at the corona vaccine that is now being developed. In this first episode: how is research on a vaccine going?

Preclinical: lab research and animal experiments

You cannot just inject a potential vaccine into people to see if it works. First, vaccine developers have to find out in laboratory and animal experiments whether they really have a promising vaccine.

There are currently according to health organization WHO nearly 179 corona vaccines in development. The vast majority of these vaccines (145) are still in the animal and lab phase. Scientists call this the preclinical phase. We will have to wait and see how many of these vaccines can be tested on humans.

Ben van der Zeijst, emeritus professor of Vaccinology at the LUMC, told Wednesday in the podcast This will be the news that many vaccines die relatively early in development.

Vaccine developers who could quickly take the step to testing on humans were often already working on a vaccine against another disease. They are now applying the techniques they were previously researching in the development of a corona vaccine. So was the University of Oxford already working on the development of a vaccine against MERS, among others.

Phase 1 and Phase 2: safety

If there is sufficient evidence from preclinical research that the potential vaccine is safe and effective, then it can be tested in humans. This is initially done in phase 1 study. In phase 1, a small group of healthy participants will investigate whether the vaccine does not lead to serious side effects and whether it causes the immune system to take action.

Several vaccine manufacturers have chosen to start the phase 2 trial before the phase 1 trial is completed. In phase 2 the same research is done as in phase 1, but then the researchers look at specific groups such as the elderly. The effects of different dosages can also be investigated. The Leiden-based vaccine developer Janssen is currently working on such a study in the Netherlands. 135 people are being recruited for this.

At present, the results of these initial studies are from Modern, BioNTech at Pfizer, University of Oxford and AstraZeneca and the Russian Gamaleya-instituut already known. So far, a fairly similar picture emerges: no serious side effects were detected and there was an immune response. The studies did differ greatly in design. For example, the University of Ofxord’s vaccine study involved more than 1,000 people, while the Russian study included only 76 people.

Only when the first and second phase have been completed, an investigation can proceed to the third and final phase.

Phase 3: does it work?

In phase 3, the vaccine will be tested on tens of thousands of people. This should clarify whether the vaccine works and whether there are side effects that did not surface in earlier phases of the study. At this stage, it must be proven that the vaccine really ensures that fewer people become ill from the corona virus.

For this reason, it is important that the coronavirus is still circulating in the country or region where the vaccine is being tested. Vaccine developer Janssen informs that it is therefore unlikely that the phase 3 study of the company will be conducted in the Netherlands. “This study is being set up in countries where the virus is still very active. Fortunately, the virus is better controlled in the Netherlands than in a number of other countries,” said a spokesman.

According to professor Van der Zeijst, there are several vaccine developers who may soon be able to supply a safe and effective vaccine. “Moderna, Pfizer and BioNTech and AstraZeneca with the University of Oxford are the furthest at the moment, but it all depends on the phase 3 trial. That will give you the information you need to evaluate the vaccines.”

The director of Pfizer said last week probably in October to know whether the vaccine that the pharmaceutical company is developing together with BioNTech also works.


Once the research is completed, you cannot immediately vaccinate millions of people. Before a vaccine can be used within the EU, it must be evaluated positively by the European Medicines Agency (EMA). The EMA looks at all research data and uses this to assess whether the vaccine is sufficiently effective and whether the risks are so small that they are acceptable.

The Dutch Medicines Evaluation Board – which is part of the EMA – previously told that a potential corona vaccine is being viewed as critically as any other vaccine. However, due to the social importance, there are possibilities to speed up the assessment procedure. For example, more people can be put on it.


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