Does it make sense to develop a substance that, when introduced into the human body, would allow a person to be heated above 42 ° C so that viruses can be killed?

Dousing with ice (below +11 degrees) water raises the body temperature to the maximum tolerated by this particular person (41 - 43). And this does not require substances, which will probably have much more contraindications than dousing. After pouring, the temperature itself returns to normal in 5 to 10 (or so) minutes. You can douse yourself regularly, you can 6 times a day. If there are chronic, etc. diseases, you probably need a doctor's consultation. Many people start by dousing their feet.

When the human body is heated to such a temperature, irreversible denaturation of proteins involved in vital processes occurs, and it is highly likely that a person will simply die or fall into a coma. A body temperature above 40 ° C is deadly. It is unacceptable to deliberately expose human life to such a risk.

Such a substance was already developed at the beginning of the twentieth century to combat syphilis. His name is sulfozin. It is a suspension of sulfur in oil, usually peach or olive oil. When administered intramuscularly to a person, this substance, in addition to an increase in temperature, causes severe muscle pain, immobility and even tissue necrosis, as a result of which sulfozine was recognized as ineffective and dangerous. However, these properties have made it popular as a punitive tool for political dissidents and the pacification of violent mental patients. It is worth noting that this use of this substance was practiced mainly in the USSR. In modern Russia, sulfozine is still used in psychiatric hospitals, but to a limited extent.

Not really. The fact is that in this way the viruses were already killed, but not in all cases the person survived at all. No one will risk a person's life in case of HIV, for example, when one can live and live with such a diagnosis.