From John. C:
People are now getting Gmail invitations from “friends” inviting them to attend special events. The message includes a link to click on to accept the invitation. If they do, then all of their Google contacts are then hacked resulting in an even larger list being sent from even more people.
The safe thing is to use an icloud email for friends and businesses and use only the Apple Contacts (wipe the Google contact list) for your email list. Use a gmail email only for things that do not allow an option for using an icloud email. Use either an Apple email alias (maximum three) for business, or elect to use the Apple “hide my email” for temporary use.