Shingrix® is a vaccine against shingles, a disease that causes a painful rash on one side of the body. Shingles is essentially a re-activation of the same virus that causes chickenpox — Varicella zoster — after remaining dormant for decades into adulthood.
Merck & Co., the manufacturer of an older shingles vaccine called Zostavax®, is facing lawsuits from people who were infected with the Varicella virus and developed shingles after being vaccinated.
There have also been reports of people who died of severe infections because they were too sick to fight off the live virus in Zostavax.
Unlike Zostavax, Shingrix is not capable of causing infections because it contains only a few specific parts of the Varicella virus that are necessary to trigger an immune response.
The Advisory Committee on Immunization Practices (ACIP), which advises the CDC on vaccine usage, recommended that all adults over 50 get vaccinated with Shingrix.
Experts also recommended that adults who received Zostavax, a shingles vaccine made by Merck, be re-vaccinated with Shingrix.
Shingrix has a few advantages over Zostavax. It does not need to be refrigerated, which means Shingrix can be sold in parts of the world where electrical refrigeration is unreliable.
Furthermore, while Zostavax is only 51% effective at preventing shingles and immunity wanes quickly, Shingrix is 97% effective for people between 50 and 69 and 91% effective for people 70 or older.