Potency of clinical group B streptococcal conjugate vaccines

The potency of clinical group B streptococcal (GBS) capsular polysaccharide -protein conjugate vaccines has been assessed with use of a mouse maternal vaccination-neonatal pup challenge model of GBS disease. Two of the three c onjugated GBS vaccines bottled as liquid preparations showed a potency redu ction from 100% to less than or equal to 50% in 3 years; whereas all six va ccines bottled as lyophilized preparations with sucrose excipient exhibited no loss of potency Juring the same span of time. A reconstituted GBS conju gate vaccine remained potent and antigenically intact after 31 days' storag e at 2-8 degreesC. These data suggest that lyophilization in the presence o f sucrose extends the potency of GBS conjugate vaccines. (C) 2001 Elsevier Science Ltd. All rights reserved.