Healthcare

Pneumococcal conjugate vaccine (PCV) is vaccine used to protect infants and young chidren against disease caused by the bacteria called pneumococcus such as invasive pneumococcal disease that approximately kills one million children worldwide every year.

However, from recent findings that presented at the 50th Interscience Conferene on Antimicrobial Agents and Chemotherapy said that this pneumococcal vaccine in childhood have no indirect effect to prevent pneumonia in adults.

The author of the study explained that community-acquired pneumonia is a major public health problem in adults, resulting in hospitalization, morbidity, use of antibiotics, and even mortality. Previous studies have suggested that vaccinating children could have an indirect preventive effect on adults.

However, according the author, based on their data analysis in Quebec, they found no indirect effect, and he stated, “The main implication of this study is that we have to develop new effective vaccines for adults against pneumococcal disease.”

The lead author of the study, a professor of public health at Laval University in Quebec City, Quebec, Philippe De Walls, PhD, and colleagues has been established the study based on medical records of Quebeckers 20 years or older diagnosed with pneumonia and admitted to the hospital between January 1, 1990 and December 31, 2007.
A total of 211,644 hospital discharges for all-cause pneumonia were identified, representing close to 100 million person-years of observation.

As of 2007, more than 90% of children younger than 5 years of age in the program received at least 1 dose of the vaccine, almost 80% received at least 2 doses, and about 50% received at least 3 doses.
However, the frequency of hospital admissions for those 20 to 39 years of age and for those 40 to 59 years of age remained stable over time. Patients 60 to 79 years of age had increased rates of hospitalization after 1993 that persisted to 2007.

Dr. De Wals stated, “We really have no satisfactory explanation for the upward break in baseline observed in elderly patients from 1993 on.”
He speculated that comorbidities in the elderly could have aggravated the severity of pneumonia, leading to more frequent hospitalizations in this age group.

An improved version of PCV (PCV-13) is now used in the U.S. for children. It remains to be seen whether this new vaccine as an indirect beneficial effect for adults. A more interesting strategy would be to vaccinate adults with this new vaccine; more studies are needed to support this idea.

Commenting with this findings, a professor of clinical pediatrics at the University of Arizona in Tucson, Sean P. Elliott, MD, said, “I fully support the wish to develop better pneumococcal vaccines for children and adults.”

For reference, Dr. De Wals reports receiving financial support from vaccine manufacturers such as Pfizer, GlaxoSmithKline, Novartis, and Sanofi, for this study.