NEW YORK (NYTIMES) - It took more than a year for the world to record the first 100 million coronavirus cases, and half that time to tally the next 100 million.
The third 100 million have come even faster, in barely five months, as large segments of countries, rich and poor alike, remain unvaccinated and a wily new variant has proved able to infect even those who are.
Case counts, though imperfect, have been a key barometer throughout the pandemic, a benchmark not only for governments implementing mitigation measures but also for people trying to discern the threat in their own communities.
Yet surpassing 300 million known cases - which was recorded on Thursday (Jan 6), according to the Centre for Systems Science and Engineering at Johns Hopkins University - comes as a growing number of experts argue that it is time to stop focusing on case numbers.
So far, the new Omicron variant appears to produce severe illness in fewer people than previous versions of the virus did, and research indicates that Covid-19 vaccines still offer protection against the worst outcomes.
And though cases are rising faster than ever - the United States, Australia, France and many other nations are seeing record surges - hospitalisations and deaths from Covid-19 are increasing more slowly.
But experts do worry that the sheer number of possible cases may still burden healthcare systems already strained by previous surges.
This week, Dr Anthony Fauci, the US government's top infectious disease expert, suggested that it was time to stop focusing on case counts.
"As you get further on and the infections become less severe, it is much more relevant to focus on the hospitalisations," he told ABC News on Sunday.
About 60 per cent of the world has received at least a single dose of a Covid-19 vaccine, but nearly three-quarters of all the shots have been administered in the world's wealthiest nations, leaving people in parts of Africa and Asia vulnerable.
In the United States, daily cases have risen fivefold over the past month, while hospitalisations have merely doubled.
In France, average daily cases have quadrupled to a record, while hospitalisations have risen by about 70 per cent and deaths have doubled, according to the Our World in Data project at the University of Oxford.
The trend suggests that the grim cadence seen for the past two years - a wave of infections, followed by a matching surge of hospitalisations, then deaths - has been altered, in large part because of the protection offered by vaccines.
And because of the widening availability of at-home tests in the US and Europe, official case numbers - which scientists have long argued are an undercount - may diverge more than ever from actual totals.
Not all home tests are reported to the authorities and many people may never get tested. Even before Omicron emerged, the Centres for Disease Control and Prevention estimated that only one in four US infections was reported.
Case numbers "definitely mean less than they did" earlier in the pandemic, said Dr Robert West, a professor of health psychology at University College London. "If we had this number of infections then, we'd have had an astronomical number of deaths."
Still, the known death toll remains devastating: more than 830,000 in the United States, 620,000 in Brazil, nearly half a million in India. In many developing nations with huge gaps in health data, the true number may never be known.
And Omicron's effect could be harsher among populations with less protection from vaccines. Some of the fastest increases in cases are occurring in African countries, which have the lowest vaccination rates.
Less than a handful of the countries on the continent are on track to meet a World Health Organisation (WHO) goal of administering two doses to 70 per cent of their populations, even as rich nations have offered a third.
"Booster after booster in a small number of countries will not end a pandemic while billions remain completely unprotected," WHO director-general Tedros Adhanom Ghebreyesus said Thursday.
What is clear, many experts say, is that the virus will likely become endemic, something that the world will have to live with for years to come, like the flu - and that by the time the world records case 400 million, as it surely will, that statistic will mean even less than it does now.
"I think when we had the first wave, a lot of people felt - not experts, but the public and many politicians felt - that if we could only weather the storm, we could come out the other side in the summer of 2020 and everything would be rosy," Dr West said. "We know now that is never going to be true."