If you are worried about it, there are various RFID blocking wallets and what not out there. Essentially, all you have to do is create a Faraday cage around your card and it will significantly reduce its ability to be read. Just wrapping the card in aluminum foil, for example, is typically enough.

With that said, I'm not hugely worried about it. Stealing credit card information by RFID (RFID sniffing) is no different than the many other methods credit card information is stolen. More often than than not, credit card numbers are stolen by a cashier or restaurant employee via a quick swipe of the card through a hidden illegal card reader or by someone just taking the time to write down (or photograph) your card information. These methods are less encrypted than the RFID chip and much more prolific. The only way to stop them would be by never letting anyone else see or touch your card, which isn't exactly practical.

Also, it's worth noting that, the encrypted information on an RFID chip does not include the CVV2 number required for electronic commerce, so even if they do get the number and unencrypted it, it's not like they can easily do an internet shopping spree with it.

Best thing to do is to simply keep a watchful eye on your credit statements, so that you can quickly contest and report fraudulent activity. Any good bank/credit card company should quickly cancel your card, remove the fraudulent charges from your account, start an internal investigation, and quickly send a new card out to you. It should be a relatively painless process for you, as an end customer.