Decide what to do about mixed entries

[miseminger]

In S_convalescent_plasma_escape.txt.

Describes both +/- changes to neutralization efficiency. What category should this fall under, or should it be split up?
Several similar entries about this paper.

# Mixed bag of positive and negative changes in neutralization capability of all 4 convalescent sera tested.
# Liu et al. (2021) https://doi.org/10.1101/2020.11.06.372037 [Preprint (BioRxiv)]
N450K