In both Santa Barbara and San Luis Obispo counties, COVID-19 hospitalization numbers are at their lowest since early in the pandemic. But this metric, widely regarded as one of the most accurate for measuring COVID-19 impact in a community, is no longer considered in the state’s reopening system.
Some public officials, such as Santa Barbara County 4th District Supervisor Peter Adam, have lamented the system. During a Oct. 6 Board of Supervisors meeting, Adam said that low hospitalization rates are “a great representation of why we should open up.”
But according to local public health officials and infectious disease experts, tracking the community’s COVID-19 spread is more complicated than one good metric. Each COVID-19 metric that local and state authorities track serves a distinct purpose, Santa Barbara County Public Health Department Director Dr. Van Do-Reynoso told the Sun.
“Hospitalization rate is just one of the metrics that we need to use to gauge COVID-19 spread in the community,” Do-Reynoso said. “All the metrics work jointly together. Each metric gives us a dimension, or a perspective, of this disease.”
But what distinguishes hospitalization data from metrics like testing positivity and case rate is that it’s generally not affected by how many people are tested in a community. Whether 100 people are tested or 100,000, those who are sick enough to be hospitalized will be in the hospital.
“We often look to hospitalization rates as one of the most accurate ways to measure the impact of COVID-19 on a community or county,” Dr. Lynn Fitzgibbons, Cottage Health’s infectious disease specialist, told the Sun in an email. “There is fairly consistent agreement amongst doctors across our state and our nation regarding the criteria that indicate when a patient with COVID-19 symptoms should be admitted to the hospital.”
Testing positivity and case rates—which the state uses to determine a county’s reopening restrictions—are influenced by how many people get tested.
“If one county has unlimited testing capacity—and people with and without symptoms are tested frequently—that county may find and record more cases, but a lower percent of all the tests would be positive,” Fitzgibbons explained. “On the other hand, a county with limited testing capacity may choose to test only those who are most sick, so that county may not find and record every case. In this second example, the number of cases may be falsely low in recorded data and the percent positive [may be] falsely high.”
These data variables are what Supervisor Adam took issue with during the Oct. 6 board meeting. Adam argued that the county’s shifting messaging on testing—going from a “need to be tested” to a “want to be tested” model—accounts for the peaks and troughs in cases over time.
“You’re cherry-picking your test subjects if you’re only testing symptomatic people,” Adam said.
Do-Reynoso acknowledged that testing capacity was limited at the start of the pandemic. However, she emphasized that the county is now “testing everyone who needs to be tested and wants to be tested, whether they are symptomatic or asymptomatic,” and that the majority of people who are tested at community-based testing sites do not report any symptoms.
Fitzgibbons said that hospitalization rates aren’t a foolproof measure either.
“Although accurate … hospitalization rates often give a delayed view of the state of COVID-19 in a community,” Fitzgibbons wrote. “This is because most patients who are admitted to the hospital with COVID-19 were exposed one to three weeks previously.”
This, she said, may have played into the state’s decision to stop considering hospitalization as one of the reopening metrics.
A California Department of Public Health (CDPH) representative affirmed Fitzgibbons’ conclusion.
“Hospitalization rates and hospital capacity data are considered lagging metrics,” the CDPH wrote. “Case rate and testing positivity metrics were included in the Blueprint [for A Safer Economy] to signal early on the behavior of disease transmission.”
Where we’re at now
Both Santa Barbara and San Luis Obispo counties are in the red tier of the state’s reopening system—the Blueprint—as of Oct. 20. This means that the counties are considered to have substantial spread of COVID-19 in the community. Both counties started in the purple or “widespread” tier, the worst tier to be placed in, before moving up to the red.
Fitzgibbons said that, from a medical perspective, the county’s tier assignment is on par with the spread of COVID-19 in the community.
“I think the categorization of COVID-19 activity in our county can reasonably be described as having ongoing substantial spread,” Fitzgibbons said.
If the counties’ numbers continue to improve, they’ll eventually move into the orange (moderate spread) tier and finally the yellow (minimal spread). Only nine out of the 58 counties in California have made it to the yellow tier as of Oct. 20. The majority are still in the red and purple tiers.
Though Santa Barbara County’s hospitalization numbers as of Oct. 23 remained considerably higher than SLO County—17 hospitalized versus four—Santa Barbara County is currently faring better in the state’s reopening system.
Santa Barbara County’s adjusted case rate on Oct. 20 was 4.3 percent, the positivity rate was 1.9 percent, and the health equity positivity rate—a new metric that ensures disadvantaged communities aren’t getting left behind—was 3.2 percent.
This means that the only thing holding the county back from an orange tier status is its adjusted case rate, which needs to be under 4 percent. Once it brings all metrics into the orange tier threshold, the county would need to keep its numbers there for two consecutive weeks to officially achieve orange tier status.
But an ongoing outbreak in Isla Vista—resulting in multiple fraternities and sororities being monitored by officials—is contributing to increased cases, Do-Reynoso said at an Oct. 23 press conference. As a result, the case rate is expected to be “solidly in the red still” on the county’s next Blueprint report card, which is released weekly on Tuesdays.
SLO County is not nearly as close to reaching the less restrictive orange tier. If it weren’t for the state’s case rate adjustment, the county would have regressed back to the purple tier with the Oct. 20 weekly tier assignment.
“The California Department of Public Health made the decision to update the adjustment scale to better reflect variations in case rates relevant to testing volume across counties and refined this after local health department feedback,” a CDPH representative told the Sun in an email.
Without the adjustment, SLO County’s new cases per day per 100,000 population was 7.5, a number that would have sent the county back to the purple tier. But the adjusted rate was 5.1 percent, which allowed it to stay in the red tier.
SLO County Public Health Department spokesperson Michelle Shoresman said the adjustment allows counties like SLO, which have high levels of testing, to get credit for it.
“If the case rate were not being adjusted by our high testing rate, we would not have met the red tier criteria for the last data period,” Shoresman wrote via email, adding that SLO County must remain vigilant “with taking all the protective measures we can.”
Santa Barbara County’s Do-Reynoso stated at the Oct. 23 press conference that 14 states recently set records for hospitalized cases, while California’s rates have declined—but that still doesn’t mean it’s time to reopen.
“It is really good that our hospitalization rates are going down, but we need to be mindful of the increasing cases,” Do-Reynoso said. “We are not ready to throw open the gates just based on one metric.”
Staff Writer Malea Martin can be reached at mmartin@santamariasun.com.
This article appears in Oct 29 – Nov 4, 2020.