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.
Surgical technician Kristen Parker was sentenced to 30 years in prision in 2010 after she was convicted in a case where thousands of people were exposed to Hepatitis. An investigation revealed the Parker injected herself with drugs intended for patients, in a drug-diversion scheme.