The number of choices available for getting immunized against influenza is unrivaled in the vaccine world, reports the Washington Post.

Options vary in the way they are produced, the way they are delivered and how many strains of influenza virus they include. Also, unlike other types of vaccines, flu shots are available seemingly everywhere: not just in health clinics and pharmacies but in grocery stores, fitness centers, and pop-up fairs at schools and workplaces.

For most people, simply getting the flu vaccine — any flu vaccine — is what matters most, says David Cennimo, an infectious-disease specialist at Rutgers New Jersey Medical School in Newark. And in practice, most of us don’t really end up making a decision at all. Each clinic decides which varieties to carry, so by the time you get there the decision has been made.

Generally, the most standard flu shot is a quadrivalent vaccine, which comes in five varieties that contain the same four strains of influenza most likely to be circulating each season. The shot goes into a muscle, usually the arm.