Sen. Amy Klobuchar (D-Minn.) called on GlaxoSmithKline to do more to address the shortage of its recombinant shingles vaccine Shingrix and asked when the company will withdraw current limits on vaccine orders and resolve the nationwide shipping delays.

Because vaccination requires two doses administered two to six months apart, many patients may not be able to complete the full regimen in time, said Klobuchar, in a letter to GSK.

“While we appreciate that there is high demand for this product, we are concerned that GSK did not appear to prepare contingency plans to ensure that sufficient supplies would be available for all patients who fall within the CDC’s recommended guidelines,” she said.