David Leonhardt
By David Leonhardt
Nov. 29, 2021, 6:28 a.m. ET
The public reaction to new Covid-19 variants has followed a familiar cycle. People tend to assume the worst about two different questions — whether the variant leads to faster transmission of the Covid virus and whether it causes more severe illness among infected people.
The first of those worries came true with the Alpha and Delta variants: Alpha was more contagious than the original version of the virus, and Delta was even more contagious than Alpha. But the second of the worries has largely not been borne out: With both Alpha and Delta, the percentage of Covid cases that led to hospitalization or death held fairly steady.
This pattern isn’t surprising, scientists say. Viruses often evolve in ways that help them flourish. Becoming more contagious allows a virus to do so; becoming more severe has the potential to do the opposite, because more of a virus’s hosts can die before they infect others.
It is too soon to know whether the Omicron variant will fit the pattern. But the very early evidence suggests that it may. Unfortunately, Omicron seems likely to be more contagious than Delta, including among vaccinated people. Fortunately, the evidence so far does not indicate that Omicron is causing more severe illness:
Barry Schoub, a South African virologist who advises the government there, has said that Omicron cases have tended to be “mild to moderate.” Schoub added: “That’s a good sign. But let me stress it is early days.”
Dr. Rudo Mathivha, the head of the intensive care unit at a hospital in Soweto, South Africa, said that severe cases have been concentrated among people who were not fully vaccinated.
Dr. Sharon Alroy-Preis, a top health official in Israel, emphasized yesterday that when vaccinated people were infected, they became only slightly ill, according to the publication Haaretz.
As The Times’s Carl Zimmer wrote, “For now, there’s no evidence that Omicron causes more severe disease than previous variants.”
In the initial days after a new variant is discovered, I know that many people focus on worst-case scenarios. The alarming headlines can make it seem as if the pandemic may be about to start all over again, with vaccines powerless to stop the variant.
To be clear, there is genuine uncertainty about Omicron. Maybe it will prove to be worse than the very early signs suggest and cause more severe illness than Delta. But assuming the worst about each worrisome new variant is not a science-based, rational response. And alarmism has its own costs, especially to mental health, notes Dr. Raghib Ali, an epidemiologist at the University of Cambridge.
“Of course we should take it seriously,” Ali wrote on Twitter, “but there is no plausible scenario that this variant is going to take us back to square one (i.e. the situation pre-vaccines).”
Absent new evidence, the rational assumption is that Covid is likely to remain overwhelmingly mild among the vaccinated (unless their health is already precarious). For most vaccinated people, Covid probably presents less risk than some everyday activities.