Saint Louis University is participating in a multi-site, National Institutes of Health-sponsored clinical trial in older adults of a new vaccine designed to protect against one of the most common types of pneumonia and related diseases such as bloodstream infections and meningitis.
"We need to protect people against pneumococcal pneumonia. It's a very nasty illness and can sometimes be fatal," said Sarah George, the investigator of this trial at Saint Louis University's Center for Vaccine Development. "As you get older, your immune system ages and you are at higher risk of getting pneumonia. And if you get pneumonia, you are at higher risk of being hospitalized or severely ill."
Pneumococcal pneumonia is a lung infection that can come on suddenly and last for weeks. Symptoms include high fever, chills, chest pain, persistent or worsening cough, breathing difficulties and fatigue. Those who get pneumococcal pneumonia can get it again.
According to the Centers for Disease Control and Prevention (CDC), more than 300,000 people in the U.S. annually are hospitalized for pneumonia. Many strains of pneumococcal pneumonia resist treatment from antibiotics, making an effective vaccination program a preferable option for keeping people from getting pneumococcal infections
Saint Louis University Center for Vaccine Development researchers are studying the most effective way to protect those who are older than 50 from pneumococcal pneumonia. Two FDA-approved vaccines protect against many diseases caused by pneumococcal bacteria, but only one can protect from pneumonia. The one designed to protect against pneumonia doesn't appear to work as well in adults who previously received the older pneumococcal vaccine, which is recommended for adults age 65 and up.
The PPV23 (23-valent pneumococcal polysaccharide vaccine) has been used for 30 years to protect against invasive pneumococcal illnesses, such as meningitis or blood stream infections, but doesn't prevent pneumonia, which is a much more common disease.
A newer vaccine, approved by the FDA last year, PCV13 Prevnar (13-valent pneumococcal conjugate vaccine) - protects against 13 strains of pneumococcal disease including pneumonia, as well as more invasive infections.
However, the PCV13 vaccine doesn't evoke a strong immune response in adults who previously received the older PPV23 vaccine. After receiving the newer PCV13 vaccine, previously vaccinated adults tend to have a lower level of antibodies in their blood that help protect the body from pneumococcal bacteria than adults who never received the PPV23 vaccine.