Few scientists would have expected a first-wave COVID vaccine to be 90% effective.
Many had said that a jab that prevented just 50% of cases would be a gamechanger.
So, with almost 1.3 million deaths so far in the pandemic, you can understand why the boss of Pfizer has called this "a great day for science and humanity."
If the results are as good in high-risk elderly patients - and we don't know that for sure until the company has done more analysis - it would mean the vaccine would prevent 90% of hospital admissions and deaths.
The result comes from the phase 3 clinical trials, in which more than 43,000 volunteers have been given either the vaccine, currently code-named BNT162b2, or a placebo.
By comparing the number of COVID cases in each group, the company was able to work out the protection given by the vaccine.
It's important to stress that this is the level of protection just after the second dose. The trials haven't been going for long enough to tell whether the protection will wane, or by how much.
Nor do we yet know whether the vaccine stops the virus transmitting. If not, then there may still need to be some degree of social distancing. We would still be living with the virus.
Nevertheless this is an extraordinary result for Pfizer and BioNTech, the German biotech company that it has been collaborating with.
The vaccine uses technology that has never reached clinical use.
It contains a short strand of mRNA, the coding information that makes a tiny portion of one part the coronavirus, rather than the more traditional method of inactivating the whole virus.
It should mean the vaccine is quicker to make at scale. That's yet to be tested of course.
If further analysis of trial data later this month confirms the vaccine has no major side effects the company will file for Emergency Use Authorisation and it will be rolled out as fast as possible.
The UK has a deal for 30 million doses, enough for 15 million people, with priority being given to those most at risk.
The vaccine being developed by Oxford University and AstraZeneca is also expected to report key data this month on whether it works. Dare we hope for a similarly good result?
We're in the closing stages of the race for a vaccine. And it looks like at least one of the runners was a thoroughbred.