The numerical output shows that the infectious bronchitis viruses (family of novel corona viruses, COVID-19) have higher negative refractive indices as compared to other corona viruses. Finally refractive indices of the family of COVID-19 are investigated with respect to the EID (Electronic infusion Device) concentration of the viruses, showing that the refractive index which ranges from “−0.96725 to −0.999998” corresponds to ‘0.01 to 10000’ EID virus concentration
Refractive index of SARS-CoV-2 (the virus causing COVID-19) ranges from “−0.96725 to −0.999998” and corresponds to ‘0.01 to 10000’ EID virus concentration by using reverse calculationn(1).
The refractive index of corona viruses must lie close to the refractive index of other viruses, as it consists of the same core/shell structure. Therefore, I would recommend taking a refractive index in the neighborhood of 1.519 as published in https://www.biorxiv.org/content/10.1101/614461v2.full for murine leukemia viruses. The refractive index is highly related to virus size. As the corona-virus can be both smaller and larger than this virus, the refractive can vary between approximately 1.47 and 1.53. I do not think the refractive index of the corona virus is negative.