You can block it. The unit won't heat or cool that room anymore though. The return air does effect supply air temp. And heat pump efficiency. With a 60 degree return air temp, the heat pump is more efficient then with a 70 degree return air temp.
We are simply getting contaminated causing otherwise healthy folks to lose the function of their kidneys and for a senior citizen who is already suffering sarcopenia this can be a death sentence because of the complexities associated with Renal Failure.
Justinian's Plague. Article. During the reign of the emperor Justinian I (527-565 CE), one of the worst outbreaks of the plague took place, claiming the lives of millions of people. The plague arrived in Constantinople in 542 CE, almost a year after the disease first made its appearance in the outer provinces of the empire.