It is really critical to note that this article was published in 2006 regarding a study published in 2005. (Link to Sorenson et al, 2005). This "news" is 17 years old.

Edit: Let's look at data that are a bit more recent. These are "official" from the CDC, but they're each cited to the original papers which did the work. (Link to CDC's flu vax efficacy page). Of note, the 2020-21 data are going to be messed up because 95% of flu cases that year just magically "disappeared." It was a miracle! Thank goodness for COVID for curing the flu! /s