On 2016 May 10, Kenneth Katz commented:

Obviously an important and well crafted study. However. while I may have missed it, I do not see what I would have considered a key control: that a different flavivirus, such as Dengue, or West Nile, was unable to infect the progenitors in this system. After all, it is concluded that the infection observed is what distinguishes Zika from other flaviviruses, and implied that this accounts for the equally distinguishing, and tragic, neonatal consequences of infection.

On 2016 May 10, Kenneth Katz commented:

Obviously an important and well crafted study. However. while I may have missed it, I do not see what I would have considered a key control: that a different flavivirus, such as Dengue, or West Nile, was unable to infect the progenitors in this system. After all, it is concluded that the infection observed is what distinguishes Zika from other flaviviruses, and implied that this accounts for the equally distinguishing, and tragic, neonatal consequences of infection.