Estimating end to virus surge proves difficult

For much of the pandemic, the trajectories of the Bay Area’s COVID-19 surges have been just behind those of other major areas like New York and the United Kingdom — helping medical experts predict when cases would reach a height before coming back down.

But this time around, in the midst of a swell of cases fueled by the BA.2 omicron subvariant and its sublineages that has yet to peak, health officials say the curve’s rise and fall are harder to predict.

“I don’t have a crystal ball, but what I can share is I would guess we will continue to see peaks and valleys. How often the peaks come and how high they are and how dangerous they are, we don’t really know,” Dr. Sara Cody, the health officer in Santa Clara County, said at a news conference Tuesday.

Here are five reasons why experts say it’s hard