Two years ago Wednesday, the first case of a mysterious new respiratory disease was discovered in Wuhan, China. Now, the Omicron variant has deepened concerns about just how much longer the coronavirus pandemic will last.

The big picture: More than 5 million people have died since that first case. Most people on earth have lived through some form of lockdown. 54% of the global population has had at least one vaccination, though the shots have been distributed unevenly.

• We know much more about the disease and how to treat it, but the end still isn't in sight.

Here's a look at the world's pandemic journey over the past two years:

• Dec. 8, 2019: The first known patient in Wuhan, China experiences symptoms of a disease that would later be identified as COVID-19.
• Feb. 23, 2020: Italy becomes the first country outside of China to impose a lockdown. Much of Europe, and later the world, will follow suit.
• March 11, 2020: The WHO declares a pandemic. 4,616 deaths have been recorded.
• April 2020: School closures affect 82% of the world's students, according to UNESCO.
• Sept. 28, 2020: The world crosses 1 million deaths, with the U.S. and Brazil recording the most deaths.
• December 2020: The FDA authorizes the Pfizer vaccine for emergency use Dec. 11, followed by the Moderna vaccine Dec. 18.
• March 24, 2021: With a brutal second wave taking hold, powered by the Delta variant, India suspends vaccine exports. India will become the global pandemic epicenter.
• Early July, 2021: After falling sharply in the spring, cases begin to rise again in both the U.S. and EU, with the unvaccinated hit hardest.
• July 29, 2021: Israel announces that it will begin administering booster shots, starting a trend across most wealthy countries.
• Nov. 1, 2021: The official worldwide death count hits 5 million.
• Nov. 5, 2021: Half of the global population has had at least one shot.
• Nov. 25, 2021: South Africa reports the Omicron variant.