Throughout the Covid-19 pandemic, there’s been one hope that we’ve all relied on. We’re all waiting, with bated breath, for the day that scientists announce a successful coronavirus vaccine, because then we can get a jab and go back to the humdrum existence we enjoyed in 2019.

And, according to Russia, that day is today. In the last 24 hours, Vladimir Putin has apparently approved the world’s first coronavirus vaccine. Big news indeed.

But a lot of people are understandably confused at this announcement. We’ve been told for months that the race to find a vaccine is more of a marathon than a sprint. Even the optimistic targets of the most advanced vaccine programs are only aiming to start delivering doses at the end of 2020. How is it that Russia has managed to score the ultimate coup and finish testing a vaccine months before anyone else?

It turns out, unfortunately, that they haven’t really. In actual fact, the only discernible difference between Russia’s vaccine and any of the others you’ve seen in the news is that this one has skipped most of the testing phases that come before licensing. We actually have no idea if it is safe and effective at all. Let me explain. Vaccines – and most other medical interventions – are tested in four phases of human experiments. Phase one trials are very simple – give the vaccine to a small group of people at different doses to see which one is safe. Phase two trials go bigger, with a few hundred people, and usually compare the vaccine against a control to a) make sure that it is triggering an immune response and b) see if there are serious side-effects that the phase one trial missed. Phase three trials are the biggest pre-licensure studies, and they test whether the vaccine actually works – they randomly allocate people into two groups, vaccine versus control, and follow them over months to see if the people who received the vaccine get infected less than people who get the control. These trials are huge, with tens of thousands of participants, so they can also look for rare side-effects that the smaller studies cannot pick up. Phase four trials are post-licensure, and are there to check whether the vaccine causes any really rare issues, because you might not pick up something that happens one in 1,000,000 times until you vaccinate enough people.