Several years later, Mister Harrison built a second clock.

VOA: special.2010.07.14

A second landing was made four months later.

VOA: special.2009.07.22

The first step uses a bit of influenza DNA to get the patient's immune system to begin fighting off the flu, and then the protection is given a "boost" some time later by the second step, which can be either another bit of DNA or a conventional flu vaccine.

VOA: standard.2010.07.21