I mostly avoid red meat for (non-vegan reasons) but I admit the article gave me pause. Luckily it also clarifies:

There is a growing body of evidence about the detrimental health effects of consuming too much red meat and dairy, so this study shouldn’t be taken as an excuse to eat more cheeseburgers and pizza; rather, it indicates that nutrient supplements such as TVA could be used to promote T cell activity.

Basically just take supplement and keep avoiding the meat :P