WASHINGTON - Flu vaccination is no longer merely a choice between a jab in the arm or a squirt in the nose. This fall, some brands promise a little extra protection. For the first time, certain vaccines will guard against four strains of flu rather than the usual three. Called quadrivalent vaccines, these brands may prove more popular for children than their parents. That's because kids tend to catch the newly added strain more often. These four-in-one vaccines are so new that they'll make up only a fraction of the nation's supply of flu vaccine, so if you want a dose, better start looking early. But that's only one of an unprecedented number of flu vaccine options available this year. Allergic to eggs? Egg-free shots are hitting the market, too. Plus there's growing interest in shots brewed just for the 65-and-older crowd, and a brand that targets the needle-phobic with just a skin-deep prick.