SLO County added more than 2,000 COVID cases in November. What drove the surge?
After struggling to contain the COVID-19 outbreak for the better part of nine months, San Luis Obispo County suffered an onslaught in November as case counts soared and record-breaking highs seemed to occur on almost a weekly basis.
The surge mimicked a trend seen throughout the state and pushed the county out of the red tier into the most restrictive purple tier, where it’s remained for four weeks.
Across the county, cities experienced alarming surges in their case counts, according to data on ReadySLO.org, with raw numbers and rates of increase rising at levels unprecedented in how the pandemic has unfolded locally.
The results were dramatic.
By mid-November, county Public Health Officer Dr. Penny Borenstein knew that the rate of rising cases locally and across the state was unprecedented.
“The rate of rise in our jurisdiction is quite sharp,” Borenstein said at a Nov. 18 press briefing. “Statewide, also, this is different that the rise in July. ... In California, in one week’s time we’ve seen a 50% increase in the number of cases.”
The average number of new cases per day tripled. In a matter of two weeks, the adjusted case rate also tripled. Active cases reached all-time highs. The county saw its three highest single-day counts occur in November.
Yet, the news wasn’t all bad. Hospitalizations remained low and continue to be a bright spot.
In total, 2,001 coronavirus cases were reported in November in San Luis Obispo County.
That’s around 800 more cases than the second-highest monthly tally in August and nearly a third of the county’s total case count.
COVID-19 testing increases in November. So does case rate
November was the worst month in terms of case rate and transmission in San Luis Obispo County since the coronavirus pandemic began.
The three highest daily new case counts were recorded in November, with an all-time high of 128 new cases reported on Nov. 7.
Active cases reached new limits in November as well, peaking at 1,032 active cases on Nov. 28.
November’s daily case average also shot up to 66.7 new coronavirus cases per day. The daily average for the month was triple that of October’s average.
The second-highest daily average for a single month, July, trailed well behind November, by around 28 new cases per day.
The increased was reflected each week in the county’s unadjusted case rate, which rose to 21.5 new cases per day per 100,00 people by the end of November, according to the California Department of Public Health. That compares to an unadjusted case rate of 6 new cases per day reported Oct. 27.
Those raw numbers pushed the adjusted case rate above the threshold to remain in California’s red tier. However, increased testing has brought the county slightly closer to red tier metrics recently.
The county was placed in the purple tier on Nov. 16.
While the case rate rose significantly, so did the county’s average number of tests per day.
According to data released Nov. 4, the county had been conducting an average of 395.4 tests per day per 100,000 residents. With San Luis Obispo County’s population, that turns out to be around 1,102 tests per day.
As of Dec. 1, that average was increased to 678.9 tests per day, or 1,893 tests per day. That’s a dramatic increase from just three months earlier, when the average was 596 tests per day the first week of September.
Meanwhile, the county’s positivity rate remained below purple tier metrics throughout November. As of data released Dec. 1, the county’s positivity rate was 3.8%.
Cal Poly, SLO and Los Osos see most drastic increases in cases
Paso Robles has been a coronavirus hotspot since the beginning of the pandemic locally.
It has remained the city with the highest total case count for the last eight months. However, the city of San Luis Obispo is not far behind after a surge in cases in November.
San Luis Obispo accounted for around a third — 662 — of the 2,001 coronavirus cases added in November. Cal Poly students who live on campus accounted for another 10% of November’s new cases.
The city of San Luis Obispo’s case count rise around 80% since Oct. 31. Its rate of increase was second only to Cal Poly’s on-campus community, which saw a 346% jump in coronavirus cases.
According to Cal Poly spokesman Matt Lazier, the increase in coronavirus cases among students had to do, in part, with some groups breaking social distancing guidelines.
“Our investigations into increases in positive cases informed us of unsafe behaviors by some subsets of our student population, including unsafe gatherings by some sorority chapters and residents of some University Housing facilities,” Lazier wrote in an email to The Tribune.
Lazier also said testing capacity increased, which led to finding more positive cases.
During the first week of November, the university conducted a total of 2,423 coronavirus tests. After that, the university conducted more than 4,000 tests per week until Nov. 25, according to The Tribune’s Cal Poly database.
“The university’s ongoing testing of on-campus students increased over the duration of the quarter, while the university’s positivity rate stayed at a fairly level 1.5% to 3%,” Lazier wrote. “This would indicate that much of the increase in on-campus positive cases could be attributed to the university’s increased ongoing testing.”
“Put more simply: We know that COVID-19 is in our campus and local communities, and more testing is going to produce more positives,” he added.
While San Luis Obispo and Cal Poly saw the highest increases in coronavirus cases, cases rose significantly elsewhere across the county in November.
Only four locations — the California Men’s Colony, Cambria, Shandon and San Simeon — had less than a 20% rise in coronavirus cases that month.
Los Osos, which only made up 2.4% of the 2,001 new cases, had a 73.9% increase in coronavirus cases.
In comparison, Paso Robles experienced only a 39% increase in cases from the previous month.
Young adults experience the biggest surge
More than half of local coronavirus cases confirmed in November — 52% — involved people between 18 to 29 years old, according to ReadySLO.org.
The number of cases within the young adult age group increased 71% since October.
Data on the age ranges of people within each city who tested positive for coronavirus were not available.
However, the sharp increase in young adult cases coincided with a surge in cases among Cal Poly students both living on-campus and in San Luis Obispo.
People ages 30 to 49 make up the second largest group of people who have had coronavirus in San Luis Obispo County. Until October, that age group had the most coronavirus cases in the county.
By the end of November, county residents in the 18-to-29 age group had 772 more coronavirus cases than people in the 30-to-49 age group.
Coronavirus hospitalizations remain low
Although the coronavirus case rate exploded in San Luis Obispo County after Halloween, the county did not see a related rise in hospitalizations.
Locally, hospitalizations peaked in August with 17 COVID-19 patients in local hospitals at once, according to data from the San Luis Obispo County Public Health Department.
In November, there were never more than 13 coronavirus patients in the hospital and never more than three people being treated in intensive care units at once.
The low hospitalization rate, in part, has to do with the surge in cases involving younger people.
Only 32 people 85 years old or older contracted the virus in November. In addition, 144 people between ages 65 and 84 tested positive for coronavirus that month.
County residents ages 18 to 29 made up the bulk of new coronavirus cases, Borenstein has said
Despite the low hospitalization rate, five people died due to coronavirus in November.
That’s compared to 14 coronavirus-related deaths in July, the month with the most local COVID-19 deaths.
Borenstein said community members should still be cautious.
“As has been the case in many communities, as the cases go (up), often you see the trailing increase in hospitalizations, as well as fatalities,” Borenstein said. “We have not had that experience; it doesn’t mean that we won’t.”
San Luis Obispo County doesn’t have data on the number of positive cases that are asymptomatic. However, Borenstein said that many coronavirus cases in the county have been mild or asymptomatic.
This story was originally published December 4, 2020 at 11:51 AM.
