Thursday, September 2, 2021

Unvaccinated, Unmasked, Indoors, A Vulnerable Population, Spread Of The Delta Variant

Environmental & Science Education, STEM, Health, Medicine, Society, Culture 

Ed Hessler

Shortly after the SARS-CoV-2 virus broke out in China, I saw a restaurant seating diagram from a  restaurant, I think, in Wuhan, China and how it had led to a number of infections following exposure to one infected customer. At the time there was no vaccine and it was also when standard restaurant seating (round tables) was still practiced. The image was striking and the importance of customer location was clear.

That image popped into mind when I saw the following report about a similar outbreak in a different setting, a school in the United States. The Centers for Disease Control (CDC) published a paper on an outbreak in an elementary school in Marin County, California. An  unvaccinated teacher at an elementary school in Marin County, Calif., became infected with Covid-19 but continued to teach for two days after developing symptoms but before testing positive. The teacher read aloud, while unmasked, to students despite a mask policy in the school. (my emphases)

There were 26 cases in the school traced to the teacher via whole genome sequencing, including 12 of 24 children in the teacher’s classroom, all of whom were too young to be vaccinated. As a seating chart shows, more students in the two rows seated closest to the teacher’s desk were infected compared to those in the back two rows. The other cases — three in fully vaccinated people — were in parents and siblings of students.

The paper includes a diagram of the classroom and shows the spread in the classroom and includes a list of the standard procedure schools should follow to help stop the spread of such outbreaks. Everyone should 1) wear masks correctly, 2) get vaccinated (when eligible), 3) stays home if symptoms occur, and 4) tests routinely.

The authors write "Ineligibility because of age and lack of vaccination contribute to persistent elevated risk for outbreaks in schools, especially as new SARS-CoV-2 variants emerge. However, implementation of multiple prevention strategies within schools can mitigate this risk. The rapid transmission and vaccine breakthrough infections in this outbreak might have resulted from the schoolchildren’s vulnerability because of ineligibility for vaccination, coupled with the high transmissibility of the Delta variant. New evidence of the Delta variant’s high transmissibility, even among fully vaccinated persons, supports recommendations for universal masking in schools." (my emphasis)

The full paper which includes these sections:  a summary (with an abstract), investigation and findings, public health response, and a discussion. 

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