Estimates for this exposure-to-symptom gap, called the incubation period, clocked in at about five days for Alpha and four days for Delta. Now word has it that the newest kid on the pandemic block, Omicron, may have ratcheted it down to as little as three.
If that number holds, it’s probably bad news. These trimmed-down cook times are thought to play a major part in helping coronavirus variants spread: In all likelihood, the shorter the incubation period, the faster someone becomes contagious—and the quicker an outbreak spreads. A truncated incubation “makes a virus much, much, much harder to control,” Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security, told me.
Already, that’s what this variant seems to be. In less than a month, Omicron has blazed into dozens of countries, sending case rates to record-breaking heights. If, as some scientists suspect, this variant is so primed to xerox itself more quickly inside us—including, it seems, in many people with at least some immunity—that leaves punishingly little time in which to detect the virus, intervene with antivirals, and hamper its spread.
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