The best way to protect yourself from chemical and biological disaster would certainly be a proper protection suite (gas masks are less effective). Nevertheless, it's expensive and needs a proper storage. So depending on your concern you can go through different manufacturers in order to make the right choice.

The next thing to do would be to build a safety room which you and your family can use during critical period of disaster. It's similar regarding food supplies, water storage and communicative requirements to an escape room you can build avoiding nuclear attack. The difference is that chemical refuge doesn't request such massive walls. However, it is important to have strong duct tape to seal off all chinks if it becomes necessary. When doing so make sure you'll have enough oxygen. As you probably figured it would be reasonable to build one multifunctional hideout getting your family covered in case of at least few possible disasters.

Medical treatment

As soon as you got caught in chemical or biological disaster vaccination will no longer be in use. So it becomes a question of medical treatment. There are cures for most of known biological weapon agents. However, nearly all of them need to be used quickly after initiation. Even if you can make a proper detection of which medication to use it is certainly impractical, irresponsible and even dangerous to constantly keep stock of vaccines and antibiotics for biological treatment.

If you suspect that you're infected or poisoned the best option would be to contact a hospital leaving such complex concern to professionals. Consider the possibility of making a phone call before appearing to avoid spreading the disease to others. Be psychologically ready for follow any instructions you're given.

However, there are at least two multipurpose antidotes which can be used without especial medical assistant

• Stabilized oxygen supplies. An oxygen-rich body has much stronger resistance to biological agents.
• Colloidal Silver. As a natural disinfectant and broad-spectrum anti-microbial agent it has been shown to be effective against more than 650 different bacteria and viruses.

Considering large amount of possible chemical and biological threats as well as major difficulty of them being successfully detected proper protection from such threat can easily overcome the basic level of self-defense. Therefore, it's completely up to your personal concern how far to go during your own research regarding such an ambiguous matter.