One-third of school-acquired COVID-19 cases spread into the community, documents from Fraser Health show.
The documents, dated May 7, show that 88 of cases that the health authority believes are school-acquired lead to transmission among households or the community.
The data appears to be a deeper dive into Fraser Health school exposure data released in April, but the health authority has not said why this further data was not provided at the time. The data reflects the time period between when students returned to classes in January until March 7.
Of the 2,049 cases found among school staff, teachers and students from January to early March, Fraser Health considers 267 –13 per cent – to be school-acquired. Of those, 88 lead to community or household spread.
However, Fraser Health data shows there were an additional 333 cases with “suspect acquisition in school” that were not included in the 267 confirmed school acquired cases. If those cases were added to school-based infections, that would push the percentage teachers and students who caught COVID-19 at school from 13 per cent to 29 per cent, more than doubling it.
Medical health officer Dr. Ariella Zbar said that the 333 cases are still being investigated. Zbar said the B.C. Centre for Disease Control is in charge of the whole genome sequencing and that she couldn’t comment on how long it would take to discern whether the strains of COVID-19 in the 333 suspect cases are linked to those in existing clusters.
Overall, there were 116 clusters and outbreaks in Fraser Health schools between January and early March, with Surrey by far the worst hit with 44 and Coquitlam in second place with 21.
However, she that even if all 333 suspect cases ended up being school-acquired, that still represents just an extra 0.1 per cent of the health authority’s staff, students and teachers.
Of the 267 cases that Fraser Health believes were acquired at school, 52.5 per cent were passed between students, 11.3 per cent were passed from students to staff, 21.4 from staff to students and 9.7 per cent between staff.
Fraser Health said that there were no variant of concern cases linked to school outbreaks. According to the health authority, a cluster is when ” in-school transmission is believed to have occurred between two or more individuals with laboratory-confirmed COVID-19 who attended the same school within a 14 day period.” An outbreak is when “multiple individuals with lab-confirmed COVID-19 infection when transmission is likely widespread within the school setting.”