Far too early to shout hello

All the vaccine experts I have talked to in recent months agree on two things: The search for a vaccine against covid-19 is going at record speed and the researchers will succeed - the question is only when. 

However, experts do not agree on the type of vaccine that will prove to be the best - genetic, inactivated, or protein-based. Currently, over 20 covid vaccines produced with these techniques are being tested on humans and the first results are now beginning to be ready.

The vaccine that Swedish-British Astra Zeneca is developing together with British researchers seems cautiously promising. It does not appear to cause serious side effects in the subjects and creates the reaction in the immune system that is intended - according to the results of the company's phase 1 study which became public on Monday, which included a thousand people.

But how strong the immune response the vaccine causes is uncertain. Although monkeys vaccinated earlier this year did not become seriously ill when they were then exposed to the coronavirus, they all became infected, indicating that the vaccine protects against serious illness - and thus can save lives - but not against infection. And in order to stop a pandemic, a vaccine must protect against infections. 

Astra Zeneca's vaccine is produced with an untested genetic engineering, where the body's own cells must produce the viral protein that the immune system must then respond to - and there is still no vaccine developed with this technology approved on the market. 

- We have no experience with these vaccines, they are completely untested, says Paul Offit, one of the world's foremost vaccine experts that I spoke to earlier today. 

According to him, it is not possible to draw any conclusions about either Astra Zeneca's or anyone else's vaccine until their phase three studies are complete. At least 30,000 people must be included, and the results from those vaccinated must be compared with a control group that has been given an inactive substance, Paul Offit believes. 

- Before the phase three studies are done, we can just as easily predict in tea leaves about the effects, he says.

Astra Zeneca is already underway with its phase 3 study and the results are expected later this autumn. But if it is to succeed, it is important that the company succeeds in including enough people in the control group who have been infected with the coronavirus - otherwise it will be difficult to prove that the vaccine really protects against infection, Paul Offit believes. 

A lot of work remains to be done to know for sure if we get a vaccine against covid-19. But the fact that more than twenty promising candidates are already being tested on humans, almost eight months after the disease was discovered, is nothing short of outstanding.