Methods: In 2014, HealthMap Vaccine Finder, an organization that connects the public to local vaccine providers through a searchable online map, and Uber, a mobile application that connects riders and drivers, created UberHEALTH, a 1-day opportunity on 23 October in Boston; New York City; and Washington, DC, and on 16 November in Chicago (5). Users could request delivery of influenza prevention packs to their home or office with the option for a nurse to administer 1 to 10 doses of influenza vaccine. Registered nurses were arranged through Passport Health, a company with clinics that provide travel medicine and immunization services in most urban locations in North America, and Pager, a company in New York City that provides medical services at the patient's site for common illnesses and minor injuries. The program was publicized using e-mail messages to application users; blog posts; and social media, such as Facebook and Twitter. Vaccine delivery and administration were free, and the application donated $5 for each request to the American Red Cross for childhood vaccinations. Interested persons in Chicago; Boston; and Washington, DC, were invited by e-mail to complete a 4-question online survey.