The short answer is yes, vacuum sealed salami needs to be refrigerated. The slightly longer answer is that while vacuum sealing can help to prolong the shelf life of salami, it is not a cure-all. Refrigeration is still the best way to ensure that your salami stays fresh and safe to eat.
Vacuum sealing works by removing the air from around the food, which inhibits the growth of bacteria. However, it is not a foolproof method, and bacteria can still grow in a vacuum sealed environment if the conditions are right. That's why it's important to refrigerate vacuum sealed salami, to help keep bacteria from growing.
If you are not going to eat vacuum sealed salami within a few days of buying it, it's best to freeze it. Vacuum sealed salami will last for several months in the freezer, and can be thawed and eaten as needed. Just be sure to thaw it in the refrigerator, never at room temperature.
So, to recap: vacuum sealed salami does need to be refrigerated, but it will last longer than unsealed salami. If you are not going to eat it within a few days, freeze it instead. And always thaw vacuum sealed salami in the refrigerator, never at room temperature.