The Government claims 40%.News reports were 10% for 2017.
Summary of the 2017-2018 Influenza Season | CDC
https://www.cdc.gov/flu/about/season/flu-season-2017-2018.htm
The overall vaccine effectiveness (VE) of the 2017-2018 flu vaccine against both influenza A and B viruses is estimated to be 40%. This means the flu vaccine reduced a person’s overall risk of having to seek medical care at a doctor’s office for flu illness by 40%.
This year’s flu vaccine may only be 10% effective, experts ...
https://www.cbsnews.com/news/this-years-flu-vaccine-may-only-be-10...
Flu is currently widespread in four states, including Georgia, Oklahoma, Louisiana, and Massachusetts, the CDC reports. What’s more, this year’s flu shot may not be up to the task.