IT would depend on what security you have on your computer. In general, when someone finds a way to hack into someone's computer other people find out and create a patch. When you install the new security updates for your pc, anti-virus program, or any other security software you have, it will prevent this sort of thing from happening. You just have to be sure you always update your security apps. If a new hack gets patched and you wait 3 months before you install the update, then you will be at risk for 3 months.
And the first day something new comes out that is when everyone is vulnerable (since there is no patch yet). But, like I said, companies find out and create patches to prevent the hack. So, at a minimum be sure everything you have is up to date. Otherwise, just use precautions. Unplug your webcam when you are not using it.