Cat allergy query

Two members of our family have been unable to visit us as they are allergic to cats. It affects their breathing and they have to leave the house. The cat passed away 4 weeks ago and I need to know if we shampoo all carpets and furniture, if the allergens will gradually disappear. Maybe it takes a few months - I have no idea. If anyone has any advice, Id appreciate hearing from you.

Anyone know how long cat allergens remain in the air/carpets furniture after the cat has departed. Friends of ours are allergic and don't want to invite them to stay until the air is allergen free.

Have you tried cleaning the place??

I would have thought that a really thorough hoovering, wet dusting, washing carpets and soft furnishings would make a big difference, it will subside in time after that.

I would have thought that a really thorough hoovering, wet dusting, washing carpets and soft furnishings would make a big difference, it will subside in time after that.

Thanks. Will do.