Coronavirus has been with us for a year. Here's what we still don't know

Updated 0056 GMT (0856 HKT) December 29, 2020

(CNN)When China first reported cases of coronavirus to the World Health Organization on December 31, 2019, it was described as a mysterious new strain of pneumonia. It didn't even have a name.

Within two weeks, Chinese scientists had identified the virus' genome sequence, the genetic code that makes up the virus. Within three weeks, the first test kits had been created and then shared by the WHO. And just over 11 months since the virus was reported to the WHO, the first people were vaccinated, making the shots the fastest vaccines ever developed.
The speed at which we've learned about coronavirus is unprecedented and scientists say we already know a remarkable amount.

Covid-19 reported cases and deaths

But one year on, with more than 81 million reported infections and 1.7 million deaths around the world, there's still a lot we don't know about Covid-19.
Those unknowns range from the basics -- such as how the virus started -- to the more complicated questions, including how will this pandemic end?
"We have learned a tremendous amount, but in terms of understanding anything in any real detail, we've got miles and miles to go," said Maureen Ferran, an associate professor of biology at Rochester Institute of Technology. "This is going to keep virologists and public health officials busy for decades."

Where coronavirus originated from

As governments raced to find a vaccine for the virus, one of the most basic questions fell off the public's radar: what is the origin of the virus?
The virus' origin has been dogged by confusion and conspiracy theories. Initially, the virus looked like it was connected to a Wuhan market that sold live animals, but a Lancet study published in January found that one third of the initial patients had no direct connection to that market.
Some, including US President Donald Trump, questioned whether the virus had been released after being studied or created in a Wuhan lab. Scientists say there is overwhelming evidence that the virus originated in the wild, and say the closest known relatives to coronavirus are too genetically different from Covid-19 for it to have been leaked and subsequently caused the outbreak.
Studies have found evidence that the virus may have been circulating in United States and Europe in December 2019, months earlier than first thought. Chinese state media has pushed the narrative that the virus may have originated outside of China.
But while Peter Collignon, a professor of microbiology at the Australian National University, says it's quite likely that the virus was circulating in the US and parts of Europe before the first cases in those countries were diagnosed, there's nothing conclusive to show that the virus originated outside of China. The World Health