After the short, sharp shock of Omicron, the pandemic phase of COVID-19 looks to be ending for most locations, unless a significant and severe new variant emerges. This update discusses what we’ve learned from Omicron, the prospects for the rest of 2022, and presents three potential criteria for defining COVID-19 as endemic.
Since the Omicron variant of COVID-19 was named by WHO on November 26, 2021, it has moved at lightning speed. In less than three months, Omicron has spread around the world, caused record peaks in cases in many places, 1 and is now declining just as quickly. In most places, the worst of the Omicron wave has passed leading some locations to loosen public-health measures to a degree not seen in almost two years. In contrast, some locations, such as Hong Kong, 2 are seeing their worst peak yet, and continuing to tighten restrictions.
The most likely scenario we discussed in the December 2021 edition of this article has proved to be largely accurate—Omicron is more infectious than any previous variant and evades the immunity provided by both prior infection and incomplete vaccination 3 (Exhibit 1). These factors, combined with limited behavior change from pandemic-weary populations—and the twin accelerants of transmission, holiday travel and gatherings—meant that Omicron moved through the population with remarkable speed. Fortunately, the early evidence that Omicron is, on average, less severe than Delta also proved right. 4 The worst-case scenarios were avoided. The even more infectious BA.2 sub-variant of Omicron may have worsened the wave but has not substantially changed this narrative to date. 5