The second wave of the H1N1 pandemic in Canada was more severe than the first, according to a study published in the Canadian Medical Association’s journal.

Researchers compared the clinical characteristics, demographics and patient outcomes of the two waves, and found that the second involved 4.8 times as many hospital admissions, 4.6 times as many deaths and four times as many intensive care cases.

The first wave accounted for 9.4% of all hospital admissions, 10.4% of ICU admissions and 10% of deaths, while the second wave accounted for 51% of all hospital admissions, 49.4% of ICU admissions and 53% of deaths.

However, the percentage of people who experienced severe outcomes during the second wave was lower.