You might have seen an alarming headline recently: You’re likely to get the coronavirus.
The assertion was based off an estimate from Harvard epidemiologist Marc Lipsitch, who predicted some 40 to 70 percent of all adults around the world would catch the virus within a year. Lipsitch has since revised that estimate downward and with a greater range: He now estimates it’s “plausible” that 20 to 60 percent of adults will catch the disease. (If this comes to pass, while being bad, it’s not apocalyptic: Most cases of Covid-19. are mild. But it does mean millions could die.)
In an email, Lipsitch says his model “assumes that the transmission in the rest of the world is at least fairly similar to that in China.” But “projections should be made with humility,” he adds, as there’s a lot still to uncover that will impact the forecast (like the role children play in spreading the disease).
The bottom line of his modeling, though, is that a sizable portion of the human population is at risk of catching this virus. It might not come to pass — especially if a vaccine or other treatment is developed. But it is possible.
If the virus cannot be contained, Lipsitch says, the only way for this to get under control is for 50 percent of people to become immune to it.
That could happen if the outbreak truly grows into a pandemic. If enough people get Covid-19, and develop an immune response, “essentially it creates its own herd immunity,” Grubaugh says. “But that’s after causing, you know, millions of worldwide infections.”
Obviously, that’s far from an ideal situation. (It’s also possible, hypothetically, that the virus becomes less deadly over time, through evolution: The most lethal versions of the virus essentially kill themselves when they kill their hosts.)
There is still a ways to go from the current outbreak to the numbers projected above. Some of the paths are worse than others. The risk is high, and we may not be able to contain the virus. But we do have tools to slow it down.