Does anyone know how safe such a thing could be? What keeps the virus from mutating and being dangerous?
Entropy, mostly. We're taking wild type viruses and burdening them with, from their genes' perspective, useless overhead. One would expect them to, on average, tend back towards the wild type. There is always the risk that we stumble them onto a path they wouldn't have found naturally, bump them out of a local optimum, but that's currently hypothetical.
If someone is currently pretty much guaranteed to die -- which is what the eligibility criteria sound like to me, someone correct me if I'm wrong here -- then there's less concern compared to accidentally killing someone who was doing fine before. And those initial trials will let you check for things like virus mutations.
They did the same thing with the pig heart transplant recently, did the operation on a guy who desperately needed a new heart but was ineligible for a regular transplant.
1) There are live adenovirus vaccines currently in use (e.g., https://linkinghub.elsevier.com/retrieve/pii/S0264410X163061...).
2) People report being sick from inactivated vaccines so those carcasses you mention evidently still trigger symptoms, and according to Wikipedia "most" viral vectors are designed to be incapable of replication so presumably some could transmit. Additionally, at least with Sputnik botched inactivation had been reported (by Brazil, https://www.dw.com/en/brazil-was-there-sloppiness-with-the-s...). Frankly if I get symptoms and am contagious then I will consider myself infected for all intents and purposes.
In the end, though, we can engineer non-transmittable viruses if warranted, and with proper care we successfully do so. I don't know the approach taken with the cancer-fighting virus in question but I bet proper care had been taken.
Technically you aren't incorrect but presenting the information like that is disingenuous.
It's been a while since I read the book, but it makes sense to me people failed to identify with the doctor as the bad guy at the end of the movie.
In the book, we're shown what amounts to a small love story between him and a vampire, and the living-vampires brutalizing the dead-vampires, and finally the doctor.
There's a ton of build up to the reversal that the alt ending does not seem to have.
Also notable, it's a doubly stranded DNA virus, so it will mutate less frequently than other virus families, such as ssDNA and RNA viruses.
Patients will undoubtably be monitored closely. That said, we do need to be extremely careful. Wherever it may have originated, Covid should have hopefully instilled caution and respect for safety protocols.
[1] https://journals.lww.com/journalacs/Abstract/2020/04000/Nove...
Seems to be mostly vaccinia (VACV)[2][3].
[1] https://pubmed.ncbi.nlm.nih.gov/29988502/ page 18
[2] https://www.cell.com/molecular-therapy-family/methods/fullte...
> CF33, and its genetically modified variants (CF33-hNIS-ΔF14.5L and CF33-hNIS-antiPDL1). The creation of CF33 and its sequenced genome has been previously described (11). Briefly, recombination among 9 different species/strains of orthopoxviruses [Cowpox (Brighton), raccoonpox (Herman), rabbitpox (Utrecht), vaccinia virus (Western Reserve), International Health Department, Elstree, and VACV strains Ankara (AS)] resulted in a chimeric orthopoxvirus, CF33, which did not previously exist in nature. This virus has been found to be highly specific for infection, replication within, and killing of breast cancer and pancreatic cancer (11, 12).
From
https://www.sciencedirect.com/science/article/am/pii/S107275...
The large difference between these genetically engineered viruses and ones actively spreading in the wild. They pick and modify them to not spread and get cleared by the immune system and sometimes to include vulnerabilities to treatments.
Let us know if they respond!