I've been thinking about this a few days ago when I went into the wikipedia rabbit hole about vaccinations and inoculation.

A few questions:

- How about the dengue fever scenario? (Immunity to less pathogenic strain can cause more severe reaction with a different strain). Can we asses the risk somehow?

> Apart from the time it will take to develop, trial, and mass produce a vaccine (12-18 months), it is unlikely that any vaccine will be practicable. The reason why is immunity to respiratory viruses (like corona) doesn’t last long – 6 months to 2 years

Is there any proof that this is the case with this virus?

Is is possible to do the infection outside the human body?