Immunoactive prophylaxis of recurrent urinary tract infections: a meta-analysis

Recurrent urinary tract infections (UTIs) are very common, particularly among women in their reproductive years. Alternatives to antibacterial prophylaxis are needed, particularly measures to increase host defences. Various bacterial lysates have been proposed with this indication. The objective of this review and meta-analysis was to assess the efficacy and safety of bacterial lysates in the management of recurrent UTIs. Electronic databases identified 11 studies with the descriptors 'urinary tract infection', 'immunotherapy' or 'vaccines' and 'double blind'. Seven of the studies dealt with an oral immunostimulant (OM-89), of which about five (1000 adult patients) were retained for analysis with an observation period of 6-12 months. The mean number of UTIs was significantly lower in OM-89-treated patients in all the trials analysed (mean 39%), as was the use of antibacterials. Four of the studies dealt with a vaginal vaccine, of which three small studies were retained for analysis (220 adult patients). The results suggest that this vaginal vaccine is effective when administered with a booster cycle (no recurrent UTI in 50% vs. 14% with placebo). No blind controlled studies could be identified with other bacterial lysates claiming the same indication. In conclusion, among the various immunotherapeutic products, studies were published only for one product (OM-89) that are in accordance with current standards. This product was shown to be effective under conditions of daily practice. The second product (vaginal vaccine) also appears to be effective but adequate phase III studies are necessary.