Teacher with symptoms of COVID went maskless, making her classroom an experience

The CDC released a report on Friday tracing the spread of the delta variant at an elementary school in California. It is tempting to make a story of blatant irresponsibility: a teacher was not vaccinated and read to the class without being masked. But beyond that, it provides a number of warnings about how our public health system remains under strain as we approach two years since the start of the pandemic. It also highlights again how the delta variant ensures that small mistakes can easily explode into big problems.

A rotten apple

The school in question was small, with just over 200 students and 24 staff. It is an elementary school, which means that its student body is also younger than the threshold for using approved vaccines. The school did a number of things right, however. Class sizes were small and individual classes were kept in separate rooms, with open doors and windows, and air filtration equipment installed. There was also a permanent policy requiring the use of masks in place.

But all was not ideal. The CDC notes that two of the 24 staff members were not vaccinated. Although vaccinees can clearly transmit the delta variant, they are likely to be less infectious and, in the worst case, would be for a shorter period of time.

One of the unvaccinated staff, a teacher, began to experience congestion and fatigue on May 19, issues they attributed to allergies. (The internal conversation “allergies or COVID?” Is one that I suspect most of us have had in the past year.) The person was tested but encountered a systemic problem: it took two days for the test results to arrive. back. This problem was then compounded by a few bad choices. The teacher placed too much importance on his self-diagnosis of allergies and continued to attend school. And meanwhile, while reading in class, the teacher took off their mask.

On May 23, test results returned and confirmed the teacher was infected.

At this point, the school district responded well again, closing classrooms and starting large-scale testing. But at this point, at least 12 of the 22 students in the class were infected (the parents of two students refused the test). In the two rows of seats closest to the teacher, eight of the nine students tested had infections. For the rest of the class, 28% of the students were infected.

Beyond the classroom

For reasons that are not clear, the infection spread to a second classroom – the CDC suggests this was likely due to informal interactions between students outside of the school classroom. Six cases occurred in that classroom, although at least two of those infected picked it up from a third person at a sleepover that a student’s parents hosted. Four other individual cases were identified in other classes. It is impossible to tell if this is a contact at school or community spread.

The students successfully transmitted the virus to eight parents and siblings in total. A number of cases in the community were also diagnosed at the same time. All of these viruses were closely related to the teacher’s version of the delta strain, so their relationship to the outbreak at school is uncertain. Still, the CDC notes that the community has a vaccination rate of over 72 percent, which has likely limited the extent of the outbreak.

Fortunately, none of the people infected with this epidemic required hospitalization.

All of this shows how difficult it is to get it right given the infectiousness of the Delta and its persistence in most communities in the United States. The school had reasonable policies in place, although they had failed to force all staff to be vaccinated. And these policies have been undermined by a series of problems which, at first glance, are not entirely unreasonable. Before the pandemic, it had become common for people to go to work when they felt sick, and confusing COVID-19 with allergies has likely been a widespread experience. We’ve probably all made an exception to public health best practices on things like wearing a mask at one point or another over the past year and a half. And we, as a company, have decided to accept a two-day deadline for the test results.

All of these easy-to-make mistakes are magnified when the community propagation context is higher, which is true in large areas of the United States right now. In many of these areas, political leaders are even actively interfering with attempts by schools to implement the type of policies that were in effect in Marin County.