GlaxoSmithKline ($GSK) says "unexpected global demand" for its meningitis B vaccine Bexsero has resulted in "supply constraints," which in turn has led to a shortage for private clinics in the U.K. The U.K.-based drugmaker told FierceVaccines that it hopes to have the situation resolved by summer. The drugmaker says the shortage is not affecting its agreement with the U.K. National Health Service, struck last year, to create the world's first national meningitis B vaccination program. GSK got the vaccine in its asset swap with Novartis ($NVS). The FDA approved the jab a year ago. The U.K. vax program began in the fall with the vaccine being offered to British infants at two months, four months and 12 to 13 months. More from FierceVaccines