Pneumococcal conjugate vaccine for young children.

UNLABELLED: Pneumococcal disease is a common cause of morbidity and mortality in the pediatric population. Pneumococcal infections, which account for most serious bacterial disease in infancy and early childhood, are a major cause of acute otitis media, sinusitis, pneumonia, bacterial meningitis, and bacteremia. Streptococcus pneumoniae is the causative agent in a large percentage of these infections, although other microorganisms also play a role. The recent emergence of drug-resistant strains has provided a strong incentive for preventing pneumococcal infections by vaccination. However, the capsular polysaccharide pneumococcal vaccines used to immunize adults are neither immunogenic nor protective in young children due to poor antibody responses. Therefore, research has focused on development of additional immunogenic pneumococcal vaccines to provide long-term immunity in children < 2 years of age. The most promising approach has been the development of a protein-polysaccharide conjugate vaccine for the seven serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) that most commonly cause infections in childhood. An effective conjugate vaccine that protects against these serotypes has the potential to prevent 85 percent of bacteremia episodes, 83 percent of meningitis episodes, and 65 percent of otitis media cases in the U.S. among children younger than 6 years. The Food and Drug Administration (FDA) recently approved the first protein-polysaccharide conjugate vaccine to prevent invasive pneumococcal diseases in infants and toddlers < 2 years of age. This conjugated vaccine against pneumococcus uses the same technology as the successful vaccine against Haemophilus influenzae type b. It consists of an immunogenic but inert protein coupled covalently to the polysaccharide coat of the selected strains of pneumococci. The conjugated antigen induces a more powerful, T-cell-based immune response in infants, which is developed by the time they are 2 months of age. Some important questions regarding this vaccine for children < 2 years of age: Is the vaccine safe? Is it immunogenic? Is it efficacious in preventing invasive pneumococcal disease and controlling otitis media? FINDINGS: Results of three randomized double-blind trials designed to evaluate the safety and immunogenicity of this vaccine in healthy children < 2 years of age were reported within the last three years. The studies found that the vaccine is safe and highly immunogenic for all seven serotypes. The most recent study, involving over 37,000 young children, also evaluated the vaccine's efficacy, and reported that the vaccine is highly effective in preventing invasive disease and has had an impact on otitis media. CONCLUSIONS: The heptavalent pneumococcal conjugate vaccine is safe and highly effective in preventing pneumococcal meningitis and bacteremic pneumonia in young children < 2 years of age; it is less effective in preventing otitis media. Based on the results of three well-designed studies demonstrating the vaccine's safety, immunogenicity, and efficacy, the vaccine is safe and effective for active immunization of children < 2 years of age against invasive disease caused by seven Streptococcus pneumoniae serotypes included in the vaccine. At this time, there is no clear medical consensus regarding its safety and efficacy for control of otitis media in children < 2 years of age. This application has not been evaluated by the FDA. The pneumococcal conjugate vaccine should be considered experimental, and has not been shown to be safe or efficacious for Streptococcus pneumoniae disease other than that caused by the serotypes included in the vaccine and for invasive infection, such as bacteremia or meningitis, caused by other microorganisms.

An evidence-based evaluation of percutaneous vertebroplasty.

BACKGROUND INFORMATION: Percutaneous vertebroplasty is a therapeutic, interventional radiologic procedure that involves injection of bone cement into a cervical, thoracic, or lumbar vertebral body lesion for the relief of pain and the strengthening of bone. This procedure only recently has been introduced, and is being used for patients with lytic lesions due to bone metastases, aggressive hemangiomas, or multiple myeloma, and for patients who have medically intractable debilitating pain resulting from osteoporotic vertebral collapse. FINDINGS: Results from two uncontrolled prospective studies and several case series reports, including one with 187 patients, indicate that percutaneous vertebroplasty can produce significant pain relief and increase mobility in 70 percent to 80 percent of patients with osteolytic lesions in the vertebrae from hemangiomas, metastases, or myeloma, or with osteoporotic compression fractures. In these reports, pain relief was apparent within one to two days after injection, and persisted for at least several months up to several years. While experimental studies and preliminary clinical results suggest that percutaneous vertebroplasty can also strengthen the vertebral bodies and increase mobility, it remains to be proven whether this procedure can prevent additional fractures in the injected vertebrae. In addition, the duration of effect is not known; there were no long-term follow-up data on most of these patients, and these data may be difficult to obtain and interpret in patients with an underlying malignant process, because disease progression may confound evaluation of the treatment effect. Complications were relatively rare, although some studies reported a high incidence of clinically insignificant leakage of bone cement into the paravertebral tissues. In a few cases, the leakage of polymer caused compression of spinal nerve roots or neuralgia. Several instances of pulmonary embolism were also reported. Although patient selection criteria have not been definitely established, percutaneous vertebroplasty is considered appropriate treatment for patients with vertebral lesions resulting from osteolytic metastasis and myeloma, hemangioma, and painful osteoporotic compression fractures if the following criteria have been met: o Severe debilitating pain or loss of mobility that cannot be relieved by correct medical therapy. o Other causes of pain, such as herniated intervertebral disk have been ruled out by computed tomography or magnetic resonance imaging. o The affected vertebra has not been extensively destroyed and is at least one third of its original height. o Radiation therapy or concurrent surgical interventions, such as laminectomy, may also be required in patients with compression of the spinal cord due to ingrowth of a tumor. CONCLUSIONS: Percutaneous vertebroplasty has only recently been introduced as a treatment for osteolytic lesions and osteoporotic compression fractures of the vertebrae, but early results are promising. Up to 80 percent of patients with pain unresponsive to correct medical treatment experience a significant degree of pain relief, and few serious complications have been reported. However, relatively few patients have undergone this procedure, and there are no data from controlled clinical trials or from studies with long-term follow-up. At the present time this procedure is still in the investigational stages, but may be appropriate for patients with no other reasonable options for medical treatment.