Leiden pharma starts testing Covid vaccine on humans; Dutch can participate from Sept.

Leiden-based pharmaceutical company Janssen Vaccines started testing a potential vaccine against the coronavirus on humans. The first tests will be done on 1,045 healthy adults in the United States and Belgium. If all goes well, testing will be expanded to the Netherlands, Spain and Germany in September, research leader Hanneke Schuitemaker said to Nieuwsuur.

Parent company Jonson & Johnson initially expected that the so called clinical trial phase will only start in September, but a successful preclinical phase accelerated the development of the vaccine.

The clinical phase will mainly test whether the vaccine is safe and what the possible side effects are. The actual effect of the vaccine will only be tested at a later stage, Johan van Hoof, head of Janssen's vaccine program said to Flemish broadcaster VRT. "We hope to start that phase in September," he said. "Then a lot more people will be recruited and then we'll really see if the vaccine really protects against the virus, or prevents a serious illness caused by the virus."

The expanded testing in September will focus on whether smaller doses of the vaccine are also effective, Dutch virologist Schuitemaker said to Nieuwsuur. "In the study that has now started, participants who get two vaccinations receive the doses eight weeks apart. We think that this will give the best immune response. In September we will see whether it is possible with less vaccine and whether that interval can also be shorter."

If all goes well, Janssen thinks the vaccine could be ready in the first half of 2021. This puts the Leiden-based pharmaceutical behind four other companies that are already in phase 3 of testing, in which the potential vaccine is administered to much larger groups of people. The Dutch government, with three other European countries, ordered 3 million vaccines from one of these companies, AstraZeneca. The pharmaceutical hopes to have the first vaccines ready by the end of this year.

Janssen expects to start phase 3 in October at the earliest, but the Leiden company will continue testing, Schuitemaker stressed. "Only when we are at the finish line and know which vaccines work will pharmaceuticals have a hard time marketing their product," she said to the news program. "The [World Health Organization] predicts that it will take 14 billion doses to supply the world, so it is only right that many makers have stepped up to make a vaccine. Nine out of ten vaccines fail in the final stages of development, so it is definitely not a done deal."

The Dutch government and other EU countries are also discussing possible orders with Janssen, Schuitemaker said. "No reservations have been made with us yet. The US government is investing in our development process, so we may give something back, but we will produce a billion vaccines by the end of 2021, more than we will put away there. We are making a vaccine to make available to the world."