UPDATED: Private clinics seeing shortage of GSK's Bexsero in U.K.

GlaxoSmithKline ($GSK) has been experiencing a high demand for its meningitis B vaccine Bexsero that has led to a shortage of doses for U.K. private clinics outside of the country's National Health Service.

Since September, the vaccine has been offered to British infants at two months, four months and 12 to 13 months as part of a deal between GSK and the NHS. However, The Telegraph reports that private clinics are unable to start new courses due to a shortage. GSK, in an emailed statement to FierceVaccines, cited "unexpected global demand" for the "supply constraints" that it hopes to allay by summer.

"We know the unexpectedly high demand for the vaccine reflects the importance parents have placed on protecting their children from meningitis B, so we are working hard to increase supply, and expect to have increased stock by summer 2016," a GSK spokesperson said in an emailed statement.

Children who have started the course should be able to finish with follow-up doses, GSK said in its statement. The company added that the NHS vaccination program is unaffected.

GlaxoSmithKline announced its deal with the NHS last March and the two began supplying doses last fall, making the U.K. the first country in the world with a national meningitis B vaccination program. At the time, U.K. Health Minister Jane Ellison called it a "landmark moment."

Bexsero, acquired through GlaxoSmithKline's massive asset swap with Novartis ($NVS), brought in £78 million in sales for the first 9 months of 2015.

- here's the Telegraph story