The popularity of the zoster vaccine recombinant, adjuvanted (Shingrix—GlaxoSmithKline), which is taken to prevent shingles, has left the company unable to produce it quickly enough to keep up with the demand. The vaccine is recommended for most people aged over 50 years, but many are having trouble getting it. The company says there are no manufacturing problems — it just did not expect so many consumers to want the vaccine. Most likely to develop in people over 50, shingles occurs when the chickenpox virus, which goes dormant after the childhood illness, is reactivated. It is a common ailment: one in three people will have it at some point in their lives, and it can flare up more than once. In studies, two injections of the vaccine, 2 to 6 months apart, were more than 90% effective at preventing the rash, and nearly 90% effective at warding off the nerve complications. That made it far more effective than an earlier shingles vaccine. A GlaxoSmithKline statement said: "We are shipping large volumes of Shingrix every 2 to 3 weeks and expect that schedule to continue for the remainder of the year. Patients can use the Shingrix Vaccine Finder at Shingrix.com to locate providers or pharmacies that have been offering the vaccine. It is recommended that patients call locations before their visit to ensure vaccine is available."