As Omicron continues to retreat, Dr. Bob Wachter, Chair of the Department of Medicine at the University of California, San Francisco, conducted a rapid-fire questions session with three UCSF experts on how to navigate the “new landscape.”
“This time feels a little bit different, and restrictions are being removed in many places,” Wachter said. “The messages from public health officials are increasingly optimistic and permissive.” First came the update from Dr. George Rutherford, UCSF professor of epidemiology.
National, statewide and local omicron updates: “We’re in the midst of a downturn.”
Rutherford said the U.S. has seen a 42 percent decline in cases and 11 percent decline in hospitalizations in the past two weeks. “We’re really turning the corner pretty much nationwide,” he said.
In California, “deaths continue to accumulate,” but hospitalizations are “essentially flat” and “we’ve also turned the corner” regarding case counts, Rutherford said. There were an average of 181 deaths statewide as of Jan. 31.
“But make no mistake, there is a ton of infection out there,” Rutherford noted.
Most parts of the state are “fairly deep into this,” he said, using Governor Gavin Newsom’s term “deep purple tier.” The most encouraging indicator in California is that the reproductive number of the virus (which indicates how many people a sick individual will infect) is 0.67. A reproductive number below 1 is needed to have gradual extinction of transmission, Rutherford said.
The test positivity rate in California has also fallen, from 20 percent to 14 percent, though this metric may not be as reliable, given the increasing use of at-home tests. Almost 70 percent of California’s population has been fully vaccinated against Covid-19, with 53 percent of those boosted. Rutherford said this means we are about 35 percent “really fully vaccinated.”
“We’re doing better than other parts of the state,” Rutherford said of the Bay Area, where percentages of people who’ve had two shots range from the mid-70s to mid-80s.
Recent data from Los Angeles studying reports of people with covid cases by vaccination status shows that those who are unvaccinated are four times more likely to show up in the hospital, six times more likely to go to the intensive care unit, six to seven times more likely to require mechanical ventilation, and 4.5 times more likely to die, compared to fully vaccinated and boosted individuals. Rutherford said this data is “pretty consistent with what we’ve been saying all along.”
A new lineage of the omicron variant, known as the BA.2 lineage, emerged in Europe and appears to be somewhat more transmissible than the original BA.1 lineage, though there is no evidence of increased severity and the booster vaccine seems to offer the same level of protection, he said.
Future variants and vaccine questions
Could we have a worse variant than omicron, or one that evades immunity?
Rutherford’s answer was blunt and fast: Yes.
“I suspect, with so much of the population vaccinated, we may start seeing some more immune evasion going on,” he said.
Assuming the next few months have low community spread and hospitalization rates, should the Food and Drug Administration approve vaccines for children under five?
Dr. Peter Chin-Hong, a UCSF professor of medicine, said that the situation is “a little bit controversial” because data indicates that protection among children may be less effective two to five years after they receive the shots. Researchers considered requiring a third shot for children but, in the meantime, the FDA asked Pfizer to submit its data before the third shot was approved. Chin-Hong said that “the criterion for success of the study was way too strict,” and that providing 50 percent protection with two shots “might be a good place to start off,” given how present covid is at the moment.
Should boosted individuals get a fourth shot?
Dr. Sarah Doernberg, associate professor at UCSF’s Division of Infectious Diseases, said there is good data suggesting immunocompromised individuals should get another boster, but that this should not be recommended broadly yet, as data is still emerging on whether it will provide a wider benefit.
“Three shots is extraordinarily protective, and I think that messaging is really important,” she said. “I worry a little bit if the message is ‘these shots don’t work for long,’ that people who are reluctant to get the shots might look at that and say, ‘why would I do this?’.”
Does omicron infection combined with two doses of vaccines mitigate the need for a booster?
British data indicates yes, Rutherford said, though he suspects national policies will continue to insist on boosting, as “we’re looking at the data in very much realtime, and stuff can change.”
“We know that the spectrum of people’s immunologic responses to natural infection may vary,” Chin-Hong said. For him, boosters are more predictable as a policy.
Both Chin-Hong and Doernberg said they would get a second mRNA booster if they had initially gotten the J&J vaccine followed by an mRNA booster. Rutherford said he would “sit tight,” as he advised his pregnant daughter in this situation to do, though he clarified this was not simply because of her pregnancy, but due to many factors.
Assuming that the omicron surge has settled down to early-November numbers by March, Chin-Hong said, “I would be comfortable navigating the world without a mask more than with a mask, although I say that again with trepidation.” At the moment, he said he is “wedded” to his “second skin.”
His masking policies a month from now would depend on the risk factors in his environment, and how far out he is from his booster and the antibody boost it provides.
Regarding future masking in schools, Chin-Hong said he would “probably want to keep that going as long as there’s virus circulating around,” noting that he worries about equal access to resources in different communities and that his nieces and nephews don’t seem to mind wearing them.
However, “I don’t believe the school should have masks forever,” he said. “I probably wouldn’t keep it mandatory in schools much longer than mandatory in the general population.”
Rutherford noted that different levels of schooling come with different protections and risks (especially for unvaccinated age groups), and that disruptions caused by students leaving the classroom for 10 or more days due to illness is a “much greater disruptor of education than masks.”
Testing and treatments
When an individual tests positive, when should they stop isolating and how frequently should they be testing?
The U.S. Centers for Disease Control and Prevention recommends isolating for the first five days, and wearing a mask in public for the next five days if you are asymptomatic (unless you test positive again on day five). Chin-Hong supported this policy, and said that if you take an antigen test that comes back negative before day 10, you can return to normal routines. Rutherford said that individuals who test positive again on day five should simply remain in isolation until day 10.
Regarding therapies to treat covid, Doernberg said that paxlovid is “really exciting, in that it is effective at eliminating or decreasing hospitalization and death in high-risk individuals,” but that it is “still very hard to get.” Federal supplies won’t significantly increase until summer, she predicted, which has led to a tiered system based on risk.
Paxlovid also has a long list of drugs it cannot be mixed with. If patients are prescribed paxlovid (which requires a positive covid test), they should start treatment within five days of the onset of symptoms. Other covid treatments that are less effective or harder to administer (such as those given through an intravenous drip) are still options for sick individuals.
Wachter finished the event on an uncertain, but slightly optimistic, note.
“There’s just a lot of uncertainty still, and we’ve all tried to learn how to manage that,” he said. “We have to continue managing, and hopefully we’re heading to a better place.”
See our previous Grand Rounds coverage here.