UCSF’s Dr. Monica Gandhi and medical student Kyle Hunter say there are costs to fear over the delta variant.
New fear-based headlines are popping up every day about the SARS-COV-2 delta variant, now the dominant strain in the U.S., with the focus on evidence of its increased transmissibility, questions about its particular ability to “break through” vaccine protection and the impact that the variant may have on a return to school.
The recent divergence of the World Health Organization and Centers for Disease Control and Prevention guidance around mask-wearing has contributed to confusion, as have recent recommendations by Los Angeles County for fully vaccinated individuals to mask indoors. Although it might feel like we’ve been here before with other variants, the situation in the context of high vaccination rates is totally different.
In the Bay Area, nearly 80% of the population over 18 has received at least one dose of a COVID-19 vaccine, and more than 60% are fully vaccinated. There are similar seroprevalence numbers statewide in California, especially when we consider the significant pool of natural immunity in areas that were tragically hit hard by the virus this past winter. COVID-19-related hospitalizations — the original catalyst for the public health emergency in the United States — are increasingly being decoupled from case rates.
The significance of this decoupling cannot be overstated. There are about 300 patients requiring ICU-level care for COVID-19 in the entire state — tragically among the unvaccinated — and hospitalizations are far below any level seen since the start of the pandemic. Therefore, the public health emergency of the pandemic as we knew it in California has entered a new stage.
We are now in a “control” phase in our state. Vaccines provide a force field of immunity in our communities that leave mainly unvaccinated, high-risk individuals (and those without prior COVID-19 infection) vulnerable to serious disease. That number is getting smaller every day (despite some hand-wringing over the pace of vaccinations), and the epidemiology is clear that children are not at high risk for severe disease. There is no evidence that children have served as vectors for transmission of the virus, have worse long-term outcomes or that the delta variant has led to higher rates of hospitalization in children. In fact, we are seeing exactly what we would expect to see with a successful vaccination campaign: As more adults gain immunity, children are protected, too.
This is particularly important as plans for school reopening in the fall reach high gear. The negative health and educational impacts of school closures on children are now abundantly clear. The WHO Europe’s guidance should be taken to heart by state and local officials here in California: In-person restrictions and school closure should be a measure of last resort only when there is sustained, high rates of community transmission. In most California counties, we can now follow clear metric-based guidelines to encourage school reopening and attendance.
Messaging heightened anxiety and new masking guidelines around the delta variant also sends a confusing message about vaccines and their effectiveness. One reason the vaccines are modern miracles of science is that they “teach” our immune system to create lasting protection against variants by harnessing the power of our B cells and T cells.
If you are vaccinated with one of the three vaccines approved in the U.S., your memory B cells can adapt and produce antibodies for whatever variant it sees, while your T cells prevent severe disease, even when your immune system has not seen the delta variant before. If the virus manages to make it past these barriers and you develop symptomatic COVID-19, it is likely to be a mild case. In fact, current data from the ground in Israel reports that the country is not seeing more severe breakthrough infections with delta.
This remarkable ability of the vaccines in preventing hospitalizations (as we have seen in the U.K., Canada and Israel) should drive messaging on school openings, masking, gathering and re-engaging in normal life in communities with high rates of immunity.
On the other hand, implementing public health guidelines that rely heavily on rates of positive PCR tests (that don’t incorporate cycle threshold values) in communities with widespread immunity decreases confidence in the vaccines by making them appear less effective than they are. This could slow uptake among the skeptical and does not communicate the idea that asymptomatic, positive PCR tests with high cycle thresholds are not “cases.”
One of the ironies of a successful vaccination campaign is that the more people who are vaccinated, the more cases there will be among that same population. In a perfectly vaccinated world, 100% of cases would be among vaccinated individuals until the virus no longer has a pool of hosts in which to survive. This is expected and should not be considered evidence of failure or cause for fear about new variants being detected among breakthrough cases.
It follows that we must gauge variants not by their “dominance” but rather by whether they have the ability to overwhelm local health systems. California’s health system is not at risk of being overwhelmed by the delta variant. Instead, pockets of nonimmune individuals are at risk, and we must focus on targeted, local vaccination campaigns for vulnerable communities and those with questions about vaccine safety and efficacy.
Finally, given the astonishing inequity of the worldwide vaccination campaign, we should expect new variants to emerge as long as there is a lack of collective action to address the vast majority of the world’s population who remain at risk. We know that bringing vaccines directly to people works and we know that California’s vast resources can be put towards assisting the global fight against COVID-19 in places where there is little if any, immunity. Advancing global vaccine equity — at this stage of the pandemic — as the U.N. secretary-general said in February is the “biggest moral test” before us at this time.
Given that California ranks 50th out of 50 states in resumption of in-person learning during the pandemic, we believe that California should message confidence in the vaccines to persuade remaining holdouts and focus on the public health impact of school closures at this time, even in light of the delta variant.