1 infected teacher spread to 26 others (including 12 kids in her classroom)
Case study of Delta in schools
To illustrate how transmissible Delta is in unmasked schools (and to highlight why vaccinations among teachers are important), I want to show you data from a school in California recently discussed in a CDC report. (BTW, I write this post to not shame the teacher. I write this post to highlight how easily Delta spreads in indoor spaces - and, hopefully, encourage you, teachers, to rigorously monitor your symptoms and keep those masks on.) This scenario could be any of us in states without school mask mandates, in unmasked church services, or unmasked stores/businesses.) Keep in mind this scenario was in a community with high vaccination rates, BUT among a classroom of kids too young to get a vaccine (I talk in detail about that below).
Here’s what happened:
An unvaccinated elementary school teacher went to school for two days while experiencing symptoms of cough, fever, and a headache. She initially attributed these to allergies (which a lot of us likely would and a lot of teachers probably are). A few times, the teacher took off her mask to read a book to her students. Among the 24 students in her class (of which 22 were too young to get the vaccine), 12 tested positive for COVID.
Let’s look at some of the big details from the data:
At this school, all teachers were vaccinated except two - including the teacher in this report.
The attack rate (how many became sick) was 50% - 12 out of 24 kids. 6 kids were symptomatic and the other 6 were asymptomatic. (A gentle reminder that even asymptomatic persons/kids can still spread COVID-19).
The desks were 6 feet apart and kids were advised to mask in the school setting. It was reported that masking among the kids was high. However, the unvaccinated teacher unmasked a few times to read to the students.
The attack rate in the first 2 rows closest to the teacher’s desk was 80% and lower in the back of the room (28%).
4 students from other classrooms tested positive and were all siblings of 3 students in the unvaccinated teacher’s room. This highlights how easy it is to take the virus home to other family members. Then those siblings can go back to school and spread to their own classrooms.
One of the students had a sleepover with two other students from the same grade. All three tested positive after the sleepover.
4 parents were also infected.
You can see in the figure below how Delta spread from the teacher, students in the class, siblings and parents of infected students, and the timing of the sleepover. If you look at Panel B, you can see the exponential spread that occurs over a short period of time (20 days) from the teacher.
We know that these cases were connected through genome sequencing and you can read those nerdy science details in the CDC report.
CONCLUSION (excerpts from the CDC’s report)
“This outbreak of COVID-19 that originated with an unvaccinated teacher highlights the importance of vaccinating school staff members who are in close indoor contact with children ineligible for vaccination as schools reopen. The outbreak’s attack rate highlights the Delta variant’s increased transmissibility**and potential for rapid spread, especially in unvaccinated populations such as schoolchildren too young for vaccination. However, transmission to community contacts appeared lower than that of some previously reported Delta variant outbreaks. Further transmission might have been prevented by high levels of community vaccination; at the time of this outbreak, approximately 72% of eligible persons in the city where the school is located were fully vaccinated.”
The city had a 72% vaccination rate. That’s really high for a community! BUT, we have to remember that children under 12 are ineligible for vaccinations. I’m wondering if that’s why some of the other parents and teachers who came into contact with the sick teacher and/or kids did not get sick. We know that the vaccines work really well against infection (yes, breakthrough cases occur but are rare). So, in areas with lower vaccination rates (like districts in Texas, MS, Louisiana, South Carolina, etc), you can imagine how the spread would occur quicker through unvaccinated communities.
“In addition to vaccination of eligible persons, implementation of and strict adherence to multipronged nonpharmaceutical prevention strategies including proper masking, routine testing, ventilation, and staying home while symptomatic are important to ensure safe school instruction.”
The case study was from a school that had masking among children. Imagine how spread will occur in unmasked schools in communities with low vaccination rates. That attack rate will likely be much higher. We are seeing that play out already across states (like Texas) with over 200 kids getting sick in the first 3 weeks (this is the example of Central Texas).
“These findings support evidence that the current COVID-19 vaccines with Food and Drug Administration approval or Emergency Use Authorization are effective against the Delta variant; however, transmission risk remains elevated among unvaccinated persons in schools.”
Although no infected persons were hospitalized, most of them had a vaccine. We know that vaccines prevent over 95% of hospitalizations and deaths. In areas with lower vaccination rates, outbreaks through schools that flow over into the community will affect our hospital systems. We are already seeing that in parts of Texas with low vaccination rates and schools starting with no masking.
MY FINAL THOUGHTS
This case study highlights the major potential for outbreaks in schools and how that spreads quickly in households and communities. The one above was in an area with high vaccination rates and among children with masks on. For those of you in communities with low vaccination rates and in schools without masks mandates, this illustrates the tip of the iceberg of what we will likely see this fall. Delta doesn’t play around in unvaccinated areas and is pretty efficient in infecting.
Schools systems, please implement mask mandates for teachers and students. Social distancing alone won’t work and you can read all of that data here. Parents, feel free to send this data and the one linked in the previous sentence to your school boards and administrators to advocate for both vaccinations among teachers and masking in schools.
-FNE
1 infected teacher spread to 26 others (including 12 kids in her classroom)
Not related to this article, but would you be willing to post a "response" of sorts to Dr. Katelyn Jetelina "Your Local Epidemioligist"'s pro-abortion post on FB? She says she's arguing from science why abortion be kept "safe, legal, and rare" in light of the recent ruling in Texas. I'd appreciate a rebuttal of sorts to share in light of her misguided post.
Could you please comment on the possible timing of vaccinations for children under 12? Since even vaccinated teachers can spread Delta, I am fearful for my 11 year old.