Eight 2nd grade students and two family members who are fully vaccinated have tested positive.
The school is now trying to determine if the outbreak is linked to a ventilation problem in the classroom.
They found a manual damper above the ceiling was too far closed, only allowing about 30% of fresh air into the room.
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"In that vent, there's a mechanism called a damper that basically flaps up and down and controls the amount of air that goes into the classroom. It was only allowing about 30% of the air that it should have been into the classroom," said school district spokesperson Amy Buckman.
The class is in quarantine. School officials have not seen a school-wide spread of COVID-19.
"This is the first time, out of the 258 cases that we've had in our district since September, that we had this many students in one classroom testing positive," Buckman said.
Return dates will be decided on a case-by-case basis.
"Although we didn't know what the cause is and we don't know what students do when they're not in school, we only know what they do in school, it still was enough to raise our curiosity," Buckman said.
The operations staff discovered a broken piece inside a vent right below the ceiling in the classroom, that may have contributed to the outbreak.
The school district added that diagnostics have since been run at all buildings and a deep cleaning was performed.
Lower Merion School District released the following update on its website:
As you may be aware, since last Thursday, we have been seeing a COVID-19 outbreak (now eight cases) in a second-grade class at Penn Valley Elementary School. The class has been quarantined since last Friday and we have not seen evidence of linked/in-school transmission at Penn Valley beyond that one class. LMSD Health Services continues to consult with the Montgomery County of Public Health (MCOPH) regarding this outbreak.
Because this was the first time we observed significant linked (in-school) transmission in our District, the LMSD Health Services team this week went beyond contact-tracing in an attempt to further investigate and understand conditions that could be factors in the outbreak. While the District does not have the ability to determine what strain of COVID is involved in these cases, it is able to look at other factors, such as those within the classroom.
To that end, LMSD's Operations Department completed a full assessment of the Heating, Ventilation and Cooling (HVAC) system for the impacted room. The inspection revealed that a manual damper within the ductwork above the ceiling was too far closed, allowing only (approximately) 30% of the maximum amount of fresh air it should have into this specific room. The damper can only be seen by physically going into the duct. The automated system that controls the HVAC equipment did not trigger any alerts indicating repairs were needed. As you can imagine, the HVAC systems across our buildings have thousands of parts. Even with the best monitoring and maintenance, at times, parts do break.
LMSD cannot say definitively whether the diminished fresh airflow contributed to the outbreak; however, it could be a factor. MCOPH has also noted the possibility of a variant strain of COVID-19 being a factor, citing both the rapid spread within the class and the fact that two vaccinated family members of impacted students have also tested positive. Since the discovery of the malfunctioning manual damper, in addition to the deep-cleaning that has been performed in that classroom, Operations staff ran an HVAC system sensor check and will be conducting assurance tests of air quality at all buildings over the weekend and in coming weeks. Even before the pandemic, the ventilation systems throughout LMSD's buildings met or exceeded standards. Due to COVID-19, the District increased ventilation and filtration levels in the HVAC systems, installed MERV 13 filters throughout the schools and installed bipolar ionization in large group spaces, such as cafeterias.
LMSD continues to work with and update MCOPH regarding this outbreak and all reported cases of COVID-19 within the District. We urge you to continue to follow protocols such as masking, distancing and hand-washing, and to use the daily screening tool before deciding whether a child should come to school. Please report any cases of or exposure to COVID-19 to the LMSD COVID Healthline by calling 610-645-1973 or by emailing firstname.lastname@example.org.