Amid high demand for GlaxoSmithKline's new shingles vaccine, healthcare providers are running out. Even though the company worked up what it calls a "fair and equitable" process to ship Shingrix doses, two U.S. senators are not satisfied and are urging the drugmaker do more to boost inventory levels. Senators Amy Klobuchar, D-Minn., and Tina Smith, D-Minn., wrote&nbs...