The world has now surpassed 100 million confirmed cases of the coronavirus. It's a figure that seemed almost unimaginable 12 months ago, when the first case had only just been confirmed on U.S. soil.

A year later, the pandemic shows little sign of loosening its stranglehold on billions of people's everyday lives. Cases continue to rise sharply in some parts of the world, and every day the losses mount, as more people lose loved ones to COVID-19, lose a business or lose their livelihood.

On January 15, the official global death toll from the coronavirus pandemic surpassed 2 million, according to Johns Hopkins University.

While the 2 million figure is horrifying, experts say the real death toll is likely much higher. Only confirmed COVID-19 deaths are included in the tally, which means that people who die without a firm diagnosis may not be included.

Similarly, many people will have been infected with the coronavirus without having a positive test to confirm it. In the early stages of the pandemic fewer tests were available, and testing remains inadequate in many countries now.

Nonetheless, with a world population of some 7.67 billion, according to the latest World Bank figures, the global case tally suggests that about one in every 76 people has now had the virus.

Despite countries imposing measures ranging from travel bans to school closures to full national lockdowns, the coronavirus has continued its inexorable spread, reaching every continent by December and leaving a trail of financial hardship, struggling hospitals and heartbreak in its wake.

The world passed the threshold of 1 million confirmed cases on April 2, and 10 million on June 28, according to data from Johns Hopkins University.

It took until November 7 for the world to register 50 million confirmed cases. Since then, the trend has accelerated sharply. The 90 million case mark was passed less than three weeks ago, on January 10.

Almost a quarter of the 100 million cases reported so far have occurred in the United States, data from Johns Hopkins University shows. And more than 400,000 people have died from COVID-19 in the U.S., a tragic milestone reached on the last full day of Donald Trump's presidency.

The second-worst affected country in terms of overall case numbers, India, accounts for just over one-tenth of the global confirmed cases. There have been more than 152,000 deaths there, according to Johns Hopkins.

Brazil has reported more than 8.8 million confirmed cases of the virus and 217,000 deaths, the second highest death toll after the United States.

Europe has also been badly hit and many countries have been battling to contain a second wave of infections since the fall. The United Kingdom has fared worst, with more than 3.6 million confirmed cases and more than 100,000 deaths -- the fifth highest toll in the world.

Excess mortality figures released by Eurostat, the statistical office of the European Union, indicate that around 297,500 more deaths occurred in the EU between March and October 2020 compared with the same period in 2016 to 2019.

As governments around the world seek to limit further spread of the virus, the emergence of new, more infectious variants is causing great concern to scientists.

One such variant was first detected in southeast England late last year; another has been detected in South Africa and two more in Brazil. A variation has also been seen in the US state of California that may or may not be driving renewed spread there.

The B.1.1.7 variant first seen in Britain has now been found in at least 60 countries around the world, according to the World Health Organization. The U.S. Centers for Disease Control and Prevention warned earlier this month it could worsen the spread of the pandemic.

Scientists have been racing to see whether the changes in the virus will make it as susceptible to available treatments and vaccines, amid fears that the mutations will allow them to evade some of the immunity induced by vaccination.

Research released this week provided some reassuring evidence that despite those mutations, people vaccinated against COVID-19 will be protected against the emerging new variants.

Mass COVID-19 vaccination programs seem to offer the fastest path out of the pandemic -- but countries' access to vaccine supply and the capacity to distribute and administer jabs varies greatly.

Israel, the United Arab Emirates, Bahrain, the US, Denmark and the UK have led the way in the rate of doses administered per 100 people, according to a global tracking website affiliated with Oxford University. But some countries have yet to start rolling out inoculations.

In the U.S., President Joe Biden has set a target of administering 100 million doses of vaccine in his first 100 days in office. More than 17.5 million doses had been administered across the country as of Thursday, a day after he was sworn in.

Infectious disease expert Anthony Fauci said that despite challenges with the distribution and administration of vaccines, the U.S. "can and should" vaccinate 70-85 per cent of adults by the end of summer, which could mean a semblance of normality by the fall.

In the U.K., the government aims to give everyone in the most vulnerable groups at least a first dose by mid-February, and to have vaccinated all adults by the fall.

Meanwhile, all those globally who are not vaccinated must continue to rely on the social distancing, hygiene and mask-wearing measures that have become all too familiar since COVID-19 arrived on the scene.

No one knows how many tens of millions more people worldwide will be infected with the coronavirus -- or how many millions more will die -- before this pandemic is brought under control.

According to the U.S. Centers for Disease Control and Prevention, about 500 million people, or one third of the world's population at the time, became infected during the 1918 influenza pandemic. That virus caused at least 50 million deaths, of which about 675,000 were in the United States, the CDC says.

In 2021, hopes remain high that science and modern medicine can prevail against COVID-19 with a fraction of that death toll.