Throughout the COVID-19 pandemic, it's been repeatedly said a vaccine could take years to make.
But it turns out one of the leading candidates - Moderna's mRNZ-1273 - not only took just two days to come up with, it was designed in its entirety before the virus had even been detected outside of China, where the pandemic began.
Moderna was founded in the US in 2010 to develop vaccines based on an entirely new and largely unproven technology - editing messenger RNA. Before COVID-19, no vaccine using the technology had ever been approved for use in humans.
Moderna CEO Stéphane Bancel was in Switzerland in early January when he heard about the mysterious viral outbreak in China, the New York Times reports. At the time there had only been a few dozen people infected, but the news had already made international headlines - including in Newshub on January 6 - due to its similarity to the lethal SARS virus of the early 2000s.
Bancel immediately wondered if his company's new technology could be used to develop a vaccine quickly.
On January 11, Chinese scientists made the genetic code for the new virus available publicly - and just two days later, Moderna scientists had the sequence for their mRNA-1273 vaccine figured out.
Both they and researchers at the US National Institutes of Health had quickly worked out the spike protein would be part of the SARS-CoV-2 virus, to use its official name, to focus on.
Within a couple of months the vaccine had moved to trials - lightning speed, compared to past vaccine developments.
"The mRNA approach allows you to skip many steps of the traditional vaccine production pipeline because you don’t have to choose the viral strain or grow the virus in a lab, which is very time-consuming," Levon Abrahamyan, a virologist at the University of Montreal, told Canadian news site Global News.
mRNA is injected into the patient, showing their cells how to make the spike protein the coronavirus uses to infect us - it's harmless on its own, but teaches the body what it looks like. The immune system then makes antibodies and other immune cells to neutralise it, and prepare for a potential invasion by the real thing.
No live viruses are needed at any stage. The whole process of designing the vaccine was done on computer, using the genetic data uploaded by Chinese scientists in the days previous.
At this stage, little was still known about how the virus spread - human-to-human transmission wouldn't be confirmed for another week.
The same day Moderna came up with its vaccine, the first case outside of China was reported in Thailand. Since then, tens of millions - possibly hundreds - have been infected, and 1.5 million killed.
Moderna is now seeking emergency approval for its vaccine, after trial results showed it to be far more effective than expected - blocking 94 percent of infections in the phase III trial, and appearing to have 100 percent effectiveness at stopping severe infections.