A new shingles vaccine is in short supply on Long Island and across the nation.

Pharmacist Howard Jacobson says he's having a hard time keeping up with the demand for a new shingles vaccine called Shingrix. His Rockville Centre pharmacy isn't the only one having difficulty keeping the vaccine in stock -- the shingles vaccine shortage is a nationwide problem.

"The manufacturer didn't realize...what kind of demand there was going to be for this vaccine," Jacobson says.

The vaccine became available in the U.S. about a year ago. It helps prevent the excruciatingly painful rash and blister known as shingles, which usually strikes people who've had chicken pox and are now in their 50s.

The national shortage of the vaccine is now apparently due to its success. The Centers for Disease Control and Prevention says Shingrix is 97 percent effective, compared to the previous shingles vaccine, which was only 51 percent effective.

Many pharmacies, like CVS, are reporting waiting lists of 200 people or more for the vaccine.

The manufacturer of Shingrix says it's ramping up production of the vaccine to try to meet demand.

In the meantime, people can ask to be placed on a wait list at their local pharmacy.