October 16, 2012

Pneumococcal vaccine being tested in older adults

Six sites including Group Health test higher dose, hoping for stronger immunity

Seattle, WALisa A. Jackson, MD, MPH, is leading a study of pneumococcal vaccine in older adults at six Vaccine and Treatment Evaluation Units (VTEUs) across the nation, including at Group Health. Dr. Jackson, a senior investigator at Group Health Research Institute, leads the Seattle-area VTEU.

Lisa A. Jackson, MD, MPHDr. Jackson and her colleagues plan to see if a higher dose of a pneumococcal vaccine will create a stronger immune response in older adults who received an earlier-generation vaccine against pneumonia and other pneumococcal diseases. They hope to gain new insights into the immune responses needed to provide protection.

The study, supported by the National Institutes of Health (NIH), will compare two dosages of a pneumococcal vaccine approved for children ages 6 weeks to 5 years, and adults age 50 and older. The trial will enroll up to 882 men and women ages 55 to 74. The National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, funds the VTEUs and this study.

More than 300,000 people in the United States are hospitalized annually for pneumonia, according to the Centers for Disease Control and Prevention (CDC). In 2009, pneumonia ranked eighth among the 15 leading causes of death in the United States, with adults 55 and older accounting for most (92 percent) of all pneumonia-related deaths that year.

The bacterium Streptococcus pneumoniae can cause a type of pneumonia called pneumococcal pneumonia. S. pneumoniae can infect the upper respiratory tract and spread to the lungs, blood, middle ear, or nervous system. Children younger than 5 and adults older than 65 are most susceptible to becoming ill from pneumococcal pneumonia. People who have been infected are susceptible to becoming re-infected.

For the past 30 years, the PPSV23 vaccine (23-valent pneumococcal polysaccharide vaccine), known by the brand name Pneumovax 23, has been the standard protection from invasive pneumococcal disease in adults over age 65.  While this vaccine protects against pneumococcal meningitis and bloodstream infections, it is unclear how well it protects against bacterial pneumococcal pneumonia.

The newer PCV13 vaccine (13-valent pneumococcal conjugate vaccine), known by the brand name Prevnar 13, protects against bacterial pneumonia and other invasive pneumococcal illnesses in children, but its efficacy and most effective dosage in adults is unknown. Earlier studies suggest that PCV13 may not induce as strong an immune response in older adults who previously received the PPSV23 vaccine within the past 5 years as in those who have not.

Researchers will conduct a phase IIb randomized clinical trial, involving two groups of adults ages 55 to 74. The first group, 294 participants who have never been vaccinated with the PPSV23 vaccine will receive a single 0.5 milliliter (mL) injection of the PCV13 vaccine. The second group, 588 participants who were vaccinated with the PPSV23 vaccine three to seven years before study enrollment, will be randomly assigned to receive one 0.5 mL injection of the PCV13 vaccine or 1.0 mL of the PCV13 vaccine administered as two 0.5 mL injections, one in each arm.

Researchers will evaluate participants’ immune responses via blood samples drawn 28 days and 180 days after injection, to compare responses between those who had previously been vaccinated with the PPSV23 vaccine and those who had not been. The researchers will also evaluate whether the larger, 1.0 mL, dose of PCV13 is more immunogenic than the 0.5 mL dose in participants who were previously vaccinated with the PPSV23 vaccine.

The vaccine study is being conducted at six NIAID-funded Vaccine and Treatment Evaluation Units:  University of Iowa, Iowa City; Saint Louis University, St. Louis; Cincinnati Children’s Hospital Medical Center-Infectious Diseases, Cincinnati; Vanderbilt University’s Vaccine Research Center in Nashville; Baylor College of Medicine, Houston; and the Group Health Research Institute in Seattle.

Information about the clinical trial is available at: http://www.clinicaltrials.gov/ct2/show/
NCT01654263?term=NCT01654263&rank=1
under the identifier NCT01654263.

National Institute of Allergy and Infectious Diseases
NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing, and treating these illnesses.

National Institutes of Health
NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases.

Group Health Research Institute
Group Health Research Institute does practical research that helps people like you and your family stay healthy. The Institute is the research arm of Seattle-based Group Health Cooperative, a consumer-governed, nonprofit health care system. Founded in 1947, Group Health Cooperative coordinates health care and coverage. Group Health Research Institute changed its name from Group Health Center for Health Studies in 2009. Since 1983, the Institute has conducted nonproprietary public-interest research on preventing, diagnosing, and treating major health problems. Government and private research grants provide its main funding.

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