Allergies are the result of a hypersensitive immune system. The allergic immune system misidentifies an otherwise innocuous substance as harmful, and then attacks the substance with a ferocity far greater than required.
Laying off an employee is different from firing an employee. Firing means letting a worker go for any reason, whereas a layoff refers to an employment termination based on economics, usually involving more than one worker.
You can be laid off without notice if you are laid off temporarily. In most cases, the law says you are laid off temporarily if you are laid off for 13 weeks or less. But the rules about temporary lay-off are complicated. If you are laid off, get legal advice about whether your lay-off is temporary or permanent.