As a Greenwich public-school parent, I received a survey asking for a ranking of these 3 options for the Fall: 

       A.  Alternating in two groups [week by week]
       B.  Alternating in two groups [2-3 days each week]
       C.  Fully remote learning
       [NOTE: there are ONLY these 3 options in their survey]

In ranking these 3 alternatives, please consider that Option B would more likely place infected students back in the classroom on their MOST contagious days. 

The science relates to the incubation & infectiousness cycle of this virus -- with details explained in this letter (link). 

In short, Option B potentially enables far more spread of COVID-19 than Option A -- while offering only the same percentage of on-site instruction (because A and B are both equally 50% on-site). 

Please do not choose Option B on the survey without first carefully studying the incubation & infectiousness cycle of the virus and considering the potential impact on our Town -- please consider either Option A or Option C instead. 

Thank you for your careful consideration of the virus' biology in school rotation design.