The FDA has approved Shingrix for preventing shingles (herpes zoster) in adults. The results of several studies showed that Shingrix was safe and effective.
There have been concerns about ingredients, such as thimerosal, that may be added to vaccines. Thimerosal is a kind of preservative that contains mercury. It’s added then taken out of some vaccines to keep other germs and bacteria from growing. The concern arose when early research connected thimerosal to autism. This link has since been found to be false. Shingrix doesn’t contain thimerosal.