Numbers Matter | Decoding the world’s Omicron wave peaks
As cases drop and the global Omicron wave recedes, a look into the trajectory of infections and deaths of all three waves
The global Omicron wave has finally started receding, with daily infections of the viral disease seeing a steady drop for three consecutive weeks now and deaths finally starting to fall in the past week.
As the Omicron surge started at the end of 2021, it became apparent very quickly to data scientists across the world that this wave was going to be unlike anything seen so far. Within a handful of days, the highly transmissible variant of Sars-CoV-2 became the dominating strain in nearly every region cases were reported. Soon enough it caused new cases to soar to several times the volume witnessed in previous waves.
By the time it peaked, the seven-day average of daily cases in the world had touched nearly 3.5 million new infections a day for the week ended January 25. For context as to how high this number is, in all previous surges, this number had peaked at 827,141 for the week ended April 25, 2021 (during the Delta wave), according to a tally maintained by the website, Our World In Data.
In effect, this means that the Omicron wave saw a 316% of jump in daily cases over what was witnessed during previous peaks. In simpler terms, the Omicron surge was more than three times the volume of the worst of previous waves.
Another interesting characteristic is how fast cases are receding. In the past week (ended Tuesday), there were an average of 2,252,397 new cases recorded across the world every day — that’s a 34% drop from the Omicron peak, exactly three weeks ago. When we look at the recession of the Delta wave, we see that it had contracted less than half as much — in the three weeks since it peaked, Delta wave had contracted only 16%.
This affirms a long-held view about some key characteristics of the Omicron variant — cases rise fast, then drop equally fast once seropositivity quickly picks up in society.
But what do we learn about deaths?
While the wave of new cases had been declining for three weeks now, the surge in the rate of deaths finally appears to have only flipped just this week. For the week ended February 10, there was an average of 10,902 daily deaths reported in the world. For the week ended February 14, this number had seen a marginal drop and had fallen to 10,657. To be sure, the drop in daily deaths is considerably smaller compared to the contraction seen in daily cases because, generally, the trend in deaths reflects a two-week lag in rise or drop seen in cases. This means that deaths will take a while before they catch up to the proportional drop in daily cases.
But what is interesting to note here is that the peak in deaths appears to have not even come close to the rate of surge in cases. In fact, despite cases in Omicron soaring more than three times what was seen in Delta, fatalities never even surpassed Delta levels, data shows.
This favourable deviation in deaths can be explained by three factors — vaccination, the lethality of Omicron, and expertise.
First, during the peak of the Delta wave at the end of April 2021, less than 3% of the world’s population had been fully vaccinated — this number is at 55% today. Second, scientists have repeatedly stressed that the Omicron variant causes relatively milder disease compared to other variants in the past (Delta was known to cause particularly severe disease). And finally, as time has progressed, doctors and scientists across the world have honed the treatment, medicines needed for the treatment of the disease, and as such have been devising better ways for treatment.
If the pandemic has taught us anything, it is the value of data. To help understand the battle against the pandemic, Jamie Mullick, HT’s Covid data whiz, writes Numbers Matter
The views expressed are personal