The news that Astra Zeneca's vaccine study will be suspended comes in the worst possible situation.

The whole world is waiting and hoping for a vaccine against covid-19 and Astra Zeneca is the company that is at the forefront of the hunt.

Sweden has an agreement with the company to buy at least six million doses of the vaccine, which is currently being tested on over 60,000 people, in so-called phase three studies, and it is during the tests in the UK that a worrying case of disease was discovered.

According to the New York Times, this is transverse myelitis, a nerve inflammation in the spinal cord that can be triggered by viral infections.

If the disease turns out to be linked to the vaccine, it is an unusual and serious reaction that in the worst case can lead to the entire vaccine project being shut down.

"Does not have to be the vaccine behind it"

But that suspicious, serious side effects are detected when a vaccine is tested on large groups of people is not uncommon, on the contrary.

That is exactly what these studies are for.

It is in the phase three studies that the future of a vaccine is decided, because it is only then that it is possible to know whether the vaccine works, how effective protection it provides and whether it is safe.

The challenge now for Astra Zeneca is to prove that it is not the company's vaccine that made the subject ill, which may well be the case.

When tens of thousands of people test a vaccine, some will also suffer from diseases that have nothing to do with the syringe.

"Strengthens their credibility"

We currently know nothing about how the Russian and Chinese vaccines that are also tested on humans in larger studies work - or whether even these companies have detected suspected cases of disease.

The fact that Astra Zeneca did not obscure its discovery strengthens their credibility.

It also shows that the company's monitoring system to be able to quickly detect suspected side effects linked to the vaccine works.

If we eventually get a working covid-19 vaccine that is approved for use, this very type of monitoring system will be extremely important in detecting rare side effects when several million people get the injections.

Right now, the Medical Products Agency and the Swedish Public Health Agency are working to strengthen this type of monitoring.