The speedy rollout is thanks to a combination of foresight, hard work and lucky breaks

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The speed at which effective Covid-19 vaccines have come through to authorisation has caused surprise. Compared with previous vaccines, the process has been very fast and so, naturally, people are asking how can it have happened without some kind of compromise on standards and care. Explaining it all as simply a result of the wonders of the latest scientific advances seems vague. So how has it actually come about? In reality, there are at least 10 reasons: some are about good planning, some good science and some just good luck.

The emergence of a novel coronavirus prompted a wave of global collaboration that has led to vaccines, treatments and the promise of new discoveries

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For scientists, 5 January was a turning point in the fight against the coronavirus. That day, a team led by Prof Yong-Zhen Zhang at Fudan University in Shanghai sequenced the genetic code of the virus behind Wuhan’s month-long pneumonia outbreak. The process took about 40 hours. Having analysed the code, Zhang reported back to the Ministry of Health. The pathogen was a novel coronavirus similar to Sars, the deadly virus that sparked an epidemic in 2003. People should take precautions, he warned.

The Chinese government had imposed an embargo on information about the outbreak and Zhang and his co-workers were under pressure not to publish the code. The blackout couldn’t hold. On 8 January, news broke about the nature of the pathogen and was confirmed a day later by Chinese authorities. To sit on the code now seemed ridiculous.