According to the CDC last year’s flu shot was only 36% effective.
“This report uses data from 4,562 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network (U.S. Flu VE Network) during November 2, 2017–February 3, 2018. During this period, overall adjusted vaccine effectiveness (VE) against influenza A and influenza B virus infection associated with medically attended ARI was 36%.”
I strongly believe in routine childhood immunizations that are proven to be effective (polio, mumps, rubella, etc) as well as further immunizations for healthcare workers (hepatitis B). But I usually pass on the flu vaccine. That would change if they can improve it.