UCSF's Department of Medicine Grand Rounds on May 20, 2021 included (from top left): Bob Wachter, George Rutherford, Monica Gandhi, and Peter Chin-Hong. Illustration by Molly Oleson; photos from screenshots of live event.

On this week’s Grand Rounds, UCSF’s Dr. Bob Wachter brought on three regulars armed with studies, statistics and opinions regarding the new CDC guidelines for vaccinated individuals, as well as lingering questions about schools, boosters and vaccine uptake. Despite some verbal sparring, the three shared similar opinions regarding this week’s most important questions, including why the CDC announcement was surprising for many, in a cautious but hopeful atmosphere as vaccination rates climb and case counts drop.

New mask guidelines

Regarding the CDC’s guideline that vaccinated individuals can safely be indoors without masks, UCSF professor of medicine Dr. Monica Gandhi said, “they were perfectly right and sound in their science,” but the CDC failed in its public messaging. 

If federal messaging noted that “our hospitalizations had already come down, severe disease had come down massively, cases since April 14 had been plummeting,” the public would have thought the guidance made sense, Gandhi said. “Instead, we messaged ‘We’re not fully vaccinated, this is still worrisome, stay at home, wear a mask, save lives.’ And then, all of a sudden, the good news came up and it was really shocking.”

Gandhi noted that the test positivity rate in California is 0.8 percent, and 0.3 percent in San Francisco. She said there have been 12 studies that show “about 92 to even one hundred percent reduction in you getting it in your nose to be able to pass it on to someone else” once you are fully vaccinated. 

Dr. Peter Chin-Hong, UCSF professor of medicine, agreed with Gandhi’s assessment of the CDC’s messaging failure. He prefers a “more discriminatory reopening” with vaccination and case rate threshold, and believes that California may be waiting to change its guidelines to allow people time to prepare for these changes.

Dr. George Rutherford, UCSF professor of epidemiology and biostatistics, said that the state may be waiting so business owners don’t have to be the ones enforcing masking and vaccination policies. The straightforward solution to this problem, he said, would be a digital vaccine authentication system to enter certain spaces. But both the federal and state governments have already said no to such vaccine passports. “Now we’re going to wait for a private sector solution and there’ll be 600 of them and they’ll be all over the place,” he said. 

Regarding California, Rutherford said, “it’s the right move to try and take a little extra time to get this straight and to figure out exactly how this is going to be implemented on the ground.” He also noted that the state will dispense another 8 million doses over the next 40 days. 

Gandhi noted that even before these additional doses, California already has transmission rates lower than the United Kingdom’s metric for reopening schools without masking or distancing measures (an average rate of 3 new cases per 100,000 people a day for seven days). Yesterday there were 18 cases in San Francisco out of 4,060 tests. 

Rutherford pointed out the large vaccination rate disparities between counties. Lassen, for example, has a 21 percent, and Marin, 60 percent. He suggested that in late summer or early fall, if vaccination rates are high enough (including adolescents), no one will need to wear masks.

Wachter said that, despite being vaccinated, he remains anxious about not wearing a mask, because he could still get mildly ill or develop long-haul covid. Gandhi said this is not a rational response, but noted that we are “coming off a really traumatic period,” which necessitates compassion for one another. “There is, essentially, one in a million people who got sick from covid after they had had the vaccine, out of 115 million Americans vaccinated,” she said, and pointed to several “well-done” UCSF studies that found long-term symptoms of covid do not occur after mild or asymptomatic disease. 

Chin-Hong pushed back on the one-in-a-million statistic given that everyone who is getting the vaccine is not being tested for covid, but agreed that those who want to continue masking should not be shamed.


Though school politics and vaccination laws “are incredibly complex and difficult,” Rutherford thinks most middle and high school students will be vaccinated by the start of the next academic year and that there will not be vaccine requirements. Elementary students, he said, will likely still have to wear masks, though covid’s mortality and case rate is “right in line” with all the other diseases schools require vaccinations for. 

Gandhi cited a commentary she co-wrote that indicated 40 percent of the children hospitalized with covid during a certain period were not hospitalized due to the disease, but were there for other reasons, such as broken legs. She hopes the study will reassure parents that covid does not cause more severe disease in children, so schools can reopen without masks in places where there are low case rates.

Vaccine uptake 

Gandhi highlighted four reasons why certain people are not getting vaccinated: medical mistrust in racially/ethnically diverse communities, access due to cost and time, desire to wait to make sure the vaccine is safe, and political divides among skeptics. She cited focus groups by the CDC wherein there was an 18 percent increase in Republicans saying they would get the vaccine if they could remove their masks by doing so, and called the CDC’s new guidelines “a positive motivator.” 

Chin-Hong emphasized the “travesty” of continuing structural barriers for certain communities, such as Latino men, who are unable to get the vaccine because they cannot get time off of work, or will lose income if they miss work. 

Hopeful statistics and boosters

In the United States, Gandhi said, 60 percent of eligible people have now received their first vaccine. In the Bay, that number is 77 percent. 

Though Dr. Fauci has indicated vaccine boosters may be likely, Gandhi believes this stance will change. She is hopeful that post-vaccine individuals will have “long-lasting, durable immunity,” meaning a booster isn’t necessary to bump antibody levels, unlike other vaccines for diseases such as diphtheria. Both Rutherford and Chin-Hong agreed that a booster would only be needed if a new vaccine-resistant variant emerged.

However, efficacy against variants differs among vaccine types, Chin-Hong said. “I don’t feel confident necessarily about all the vaccines around the world,” he said. This is why, as Gandhi noted several times, “No one is safe until this world is vaccinated.”

See our previous Grand Rounds coverage here.

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FREELANCER. Madison Alvarado was raised in the Bay Area and moved to San Francisco after attending undergrad at Duke University. She fell in love with reporting in high school, and after a brief hiatus is eager to continue learning and growing as a storyteller. She has been covering UCSF's Grand Rounds since the summer of 2020.

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  1. > Wachter said that, despite being vaccinated, he remains anxious about not wearing a mask, because he could still get mildly ill or develop long-haul covid. Gandhi said this is not a rational response, but noted that we are “coming off a really traumatic period,” which necessitates compassion for one another. “

    The advice from both doctors have been of tremendous help and value to me this past year, on twitter, podcasts and youtube, and because of that but I would love the timestamp where Dr. Gandhi tells Dr. Wachter his view is not rational!