The illnesses that have been occuring recently, and the deaths, appear to be due to a problem with the liquid being used -- and can happen whether you vape often or infrequently.
Of course we don't yet know the long term risks of vaping, and since there is abolutely no reason TO take it up, I'm not clear why anyone would. (It may have some use for people who are unable to quit cigarettes, as a smoking cessation tool like the patch or gum. But for people have never smoked -- why start? And if you are only doing it once a month, how is it helping you quit smoking?)