In a gloomy doctor's office in central Moscow, the patient winced as he watched the nurse prepare the syringe.

But within seconds, the jab was over. As he stepped out into the cold October sunshine, a long queue snaked down the street.

This is Sputnik V: Russia's flagship coronavirus vaccine and, as of August, the first to be registered anywhere in the world.

It was a big win for then Kremlin: ever since Covid-19 first appeared in China at the end of last year, scientists all across the globe have been racing to find a vaccine.

Some nations are moving faster than others. China has already inoculated hundreds of thousands of its citizens, and plans to distribute experimental vaccines to thousands more.

Outside observers are looking on in horror. It normally takes up to a decade to produce and approve a vaccine, but Russia and China have squeezed the process into months. Scientists have no idea if the vaccines are safe, or even if they work at all - Sputnik V was tested on just 76 people before it was approved by President Putin.

"It is a dangerous bet that could backfire," says diplomat Francois Heisbourg. "But the proof is in the pudding: if it works, they will look extremely smart."

Indeed, for politicians worldwide, the search for a vaccine is about more than saving lives. Beijing is still reeling from the backlash of its failure to contain the virus in Wuhan - producing the first successful vaccine could turn their fortunes around.

It is a battle that is becoming increasingly bitter: Western intelligence agencies have accused both Russia and China of stealing research after state-sponsored groups were caught hacking into university networks.

And despite pressure from Donald Trump, who called for a vaccine in time for US election day on 3 November, Western scientists are much more cautious than their Eastern counterparts.

As a result, the West is rapidly falling behind in this new space race. In recent weeks, trials for two of the most promising vaccines have been paused after unexplained illnesses.

Officials worry that if they approve a Covid-19 jab that later turns out to be dangerous, it will ruin public trust in vaccines forever. "We cannot cut corners, and we cannot be seen to be cutting corners," says British virologist Stuart Neil.

In the meantime, developing countries, without the resources to pay for vaccines or the technology to create their own, are looking to the East.

It is an opportunity that Russia and China are seizing with both hands. Last month, Moscow signed a deal to supply India, a valuable trading partner, with 100 million doses of Sputnik V.

At the same time, the UAE became the first country outside China to approve a vaccine made by that nation's state-run pharmaceutical group. And Beijing is hoping to mend old rifts and make new friends by offering vaccines to its neighbours in the disputed South China Sea region.

Yes, say some. For now, Russia and China are winning the race for a vaccine - and they are using their successes as proof that their authoritarian systems are superior to Western democracies. Coming out of lockdown a year ahead of the West would give them time to shift the balance of wealth and power back to the East. With liberal democracies already struggling, this could be a decisive moment.

No, say others. Moscow may have dismissed safety concerns as "jealousy", but the truth is they are playing a risky game. If their immunisations prove to be dangerous, then Russia and China could find that their hasty vaccine roll-outs backfire. And they may have got a head start, but the West is not far behind - British scientists believe they could have data from final-stage trials by December.