Even as the Omicron variant sweeps around the world, public health officials have noted that, in most cases, the number of Covid patients in hospitals remains significantly lower than during previous pandemic surges. That's not the case in the US, however, where the number of patients with the coronavirus currently in hospital has reached record numbers. According to data from the Department of Health and Human Services, 145,982 people were in hospital with the virus on 11 January, surpassing a previous record set in January 2021. On Thursday, US President Joe Biden was expected to announce plans to deploy military medical personnel to help in six of the states hardest hit by the influx of patients. Similarly, hospitals in large parts of neighbouring Canada have also seen surges, with Quebec reporting a pandemic high last weekend. So what is going on, and why might North America's experience be different to South Africa and Europe so far? What do the numbers show? Let's begin with this chart comparing how many people in several countries have been in hospital with Covid-19 during the pandemic. It's adjusted to account for population size and represents a ratio of the number of infected hospital patients per million inhabitants. The various peaks represent times in which each nation was hit by a new Covid wave, including the initial outbreak and influx of hospital patients, last winter's surge or the summer spike caused by the Delta variant. The green line, for example, shows how hard Italy was hit at both the beginning of the pandemic and again last year, reaching a high of 638 infected patients per million inhabitants on 23 November, 2020. On the right side of the chart, every country has experienced a large spike in Covid-infected hospital patients due to Omicron. What's interesting, however, is to compare the rates each country is hitting now with those previous peaks. For Italy, France, and the UK, we see that the number of patients in hospital with Covid remains much lower than in previous waves. In the UK, 291 patients with coronavirus per million were in hospital on 10 January. Just under a year ago, the ratio stood at 576 per million. In France, the ratio stood at 347 per million on the same day, compared with a high of 490 in November. In the US, on the other hand, 411 US Covid-19 patients per million people were in hospital as of 9 January - surpassing a previous peak of 400 per million set on 14 January 2021. Similarly, the data shows that in Canada, 206 people were in hospital per million as of 11 January, compared to previous peaks of 118 in April and 128 in January 2021.