A new vaccine has demonstrated success at treating shingles in the senior population, but actually finding the drug is proving difficult.

“Shingrix,” as it’s called, was recently licensed by the Food and Drug Administration, and has the blessing of the Centers for Disease Control in addressing the painful rash, the Washington Post reports. For patients in their 70s and 80s who receive the recommended two doses, the drug is more than 90% effective. That’s compared to just 41% for 70-year-olds using the old drug, Zostavax, and 18% for those in their 80s.

But that success is driving shortages of the drug across the country. As a result, the manufacturer is working to bolster supply, while implementing order limits on providers. Delays for drugs to treat shingles — a disease that affects about 1 million in the U.S. annually, with risk increasing alongside age — are expected to continue through 2018.

Flu woes

Meanwhile, a new type of flu vaccine proved more effective in helping seniors this past winter, but not nearly to the extent that was hoped, the Associated Press reports. All told, flu vaccines kept those age 65 and older out of the hospital only about 24% of the time.

Most successful was the drug Flucevax, at about 26.5% in the senior segment, according to a Food and Drug Administration study presented Wednesday in Atlanta. Such unimpressive results cam during one of the most severe flu seasons in over a decade.

“The big problem is still the same — we need better vaccines. But these incremental improvements are very important,” said Brendan Flannery, a CDC flu expert told the AP.