San Francisco Chronicle - (Sunday)
Omicron may peak after hard few weeks
Delta’s presence, public’s behavior cloud outlook
If there’s a bright side to the jaw-dropping spike in coronavirus cases reported recently in California and the Bay Area, it’s that this omicron-fueled surge may pass much faster than any previous wave of infections, though at what cost remains to be seen.
Parts of the state that reported the earliest upswings, including San Francisco, could peak in just a couple of weeks, infectious disease experts said. The Bay Area could generally be seeing the tail end of this surge by early February. Previous waves have lasted two to three months, from the first upticks to a leveling off.
Health officials warned that it’s too early to say for sure whether this surge will end faster than any other — and the damage it causes in terms of severe illness and death remains a critical source of uncertainty and concern.
“Short term, I think it’ll be a tough January. Hold on to your seat, really hard,” said Dr. John Swartzberg, a UC Berkeley infectious disease expert who predicts that much of California may see a zenith in cases around the same time as last year’s winter peak, in the second week of January.
Signs of the chaos caused by omicron already are apparent. The number of people hospitalized with COVID, in the Bay Area and California, is climbing fast — up more than 50% week over week in the region, though still far below last winter’s high point. Testing centers have been overwhelmed, with people reporting long lines or having to wait several days to make an appointment.
Cases already have passed the peak of the summer surge and are approaching last winter’s highs. Bay Area daily average cases have increased sixfold since the start of the month, and more than doubled over just the past week.
“The wave has already been set in motion. I’m predicting it will be over in a few weeks, but obviously, who knows for sure?” said Dr. Abraar Karan, an infectious disease expert at Stanford. “These things can change very quickly. In three days I may feel differently. And we’ve been through this enough times to know that complacency certainly is not helpful.”
Guesses as to how the second Bay Area winter surge will resolve are based mostly on the experiences of a handful of nations that are ahead of the United States in battling omicron, the highly infectious variant that has swept the globe with breathtaking speed. “It seems to be a flame that burns bright and burns fast,” said Dr. Matt Willis, the Marin County health officer.
South Africa, the first to identify omicron as the source of a surge in the last week of November, already appears to be well into its downslope. Cases there peaked about three weeks after they began to climb. It’s possible cases have started to level off in the United Kingdom, which began its surge in the first week of December.
But Denmark, which many Bay Area experts look to as a frame of reference due to its comparable vaccination and booster rates, began its sharp upturn in early December, and its cases are still spiking.
“If we’re going to base it on the experience in South Africa and the U.K., we’ll have really high peaks of cases, but my understanding is it then goes down rapidly,” said Dr. Karen Relucio, the Napa County health officer. “But we thought that was the way it was going to be with delta. So I’m going to cautiously say it might turn out to be a larger rise and faster fall, but it’s hard to know.”
Several variables are in play as to how quickly this surge passes and what harm it causes along the way.
One big question is how much delta remains in the community. Omicron is now believed to cause less serious illness than delta. So, if omicron truly has taken over, that could make it more likely that cases will sweep through a highly vaccinated Bay Area very quickly and with mostly mild illness. If delta is still in the mix, the picture is a bit murkier: The region could be facing a more drawn-out surge, and potentially with more severe disease.
Two weeks ago, the Centers for Disease Control and Prevention estimated that omicron made up as much as 70% of all cases in the United States — a shocking takeover because the first case here was identified only on Dec. 1. But the CDC later revised that estimate down and, as of the week before Christmas, figured omicron made up roughly 58% of all cases and delta most of the rest.
But that mix varies from state to state, and perhaps even county to county. The CDC estimates omicron makes up 55% of cases in California and the rest of the southwest region, but nearly 90% of cases in New York and New Jersey.
“If omicron is milder but we’re experiencing an increase in delta as well, that could still worsen the hospital picture,” said Dr. Nicholas Moss, the Alameda County health officer. “And I don’t think we’ll get a clear idea for probably another couple weeks of what is really circulating.”
One small but compelling study out of South Africa suggested that those who are infected with omicron have added protection against future infection by delta. If that holds up, it could bode well for how the pandemic plays out in the longer term, especially if another variant that’s an offshoot of delta arrives, infectious disease experts said. But more study needs to be done, they said.
Another factor that will help determine the course of this surge is booster uptake. Studies have found that fully vaccinated people are vulnerable to infection and somewhat to severe illness from omicron — more so than any other variant. Boosters increase protection from severe disease to roughly 90%, and raise protection against infection to about 50%.
Indeed, boosters are so important that many health experts have pushed to redefine “fully vaccinated” as including the third dose for Pfizer or Moderna vaccine recipients, or the second dose for those who got Johnson & Johnson. California has mandated that all health care workers get boosters, and many counties have expanded that to include certain frontline staff who work with high-risk communities.
In much of the Bay Area, just over half of those eligible for boosters have gotten them. Disease models suggest that number needs to climb, and fast, to more like 70% or 80% to prevent hospitals from becoming overwhelmed. But it also depends somewhat on who is getting boosted — it’s much more important that older adults and others at risk of severe illness get boosted than younger adults, though everyone should as soon as they are eligible, health officials said.
“We’re about 75% now for everyone over age 55 having received a booster shot,” said Willis, the health officer for Marin County, where about 90% of the total population is fully vaccinated. “That’s as reassuring as overall vaccination rates to me.”
One other key variable for how this surge unfolds is human behavior. Everyone’s tired, everyone’s fed up with the pandemic, and health experts say they fear a fatalism is setting in among some people that could lead to abandoning the basic protocols that prevent infection.
Just because this surge may be the most explosive yet seen in the Bay Area and the rest of the state doesn’t mean everyone will get infected and it’s OK to give up, they say. Holding on to protective measures — wearing good-quality masks, avoiding large gatherings, staying home when sick, everything else everyone is familiar with by now — will keep many people from becoming infected and stop chains of transmission.
“There are still choices we can make,” said Joshua Salomon, a professor at Stanford’s Center for Health Policy. “People should take some reassurance that there are small things you can do to minimize risk, and that those things matter, even if you don’t get to directly see the infection that you have avoided.”
Dr. Kirsten Bibbins-Domingo, vice dean for Population Health and Health Equity at UCSF, said she worries that one element of this surge will echo the trends seen in every other wave: The illness and severe outcomes will be distributed unfairly among those least able to take steps to protect themselves.
The same frontline workers — health care providers, grocery store clerks and bus drivers, for example — who couldn’t work from home any other time during the pandemic can’t now either. Many families can’t afford to upgrade their masks to better protect themselves from omicron. They can’t afford costly home test kits either, or to wait in line for an hour to get tested at a clinic. They may have a tougher time getting access to a booster shot.
“Omicron is the reminder that we can all be affected and do our part. But it is absolutely going to be the case that those who are least able to take all those steps to protect themselves in the fullest way possible are going to bear the brunt of this,” Bibbins-Domingo said. “There’s no doubt about that.”