We have probably all seen it, an influx in spam related to the subscriptions you set with Google Alerts around your web site and brands you track. But Google's John Mueller and Danny Sullivan said that influx of spam in Google Alerts should not have any impact on your Google search rankings.
Danny Sullivan from Google said this back last September:
They shouldn't have an impact on your site.
— Danny Sullivan (@dannysullivan) September 24, 2018
John Mueller from Google reassured us the other day that these comments are still valid:
Yep -- Danny's comment is still valid here.
— 🍌 John 🍌 (@JohnMu) June 20, 2019
So no need to worry according to multiple Google sources.
Forum discussion at Twitter.