Impact of PCV on Disease and Colonization Among Native American Communities

Pneumococcus is a bacterium that healthy people commonly have in their nose and throat; this
is called pneumococcal 'carriage'. Carriage is usually harmless, but can progress to
serious disease like pneumonia, meningitis, and blood stream infections or to less serious,
but burdensome, diseases like sinusitis or ear infections. Infants and the elderly bear the
greatest burden of pneumococcal disease with over 800,000 annual global deaths from this
germ among children under 5 years of age. Furthermore, pneumococcus has developed
resistance to antibiotics making it increasingly difficult to treat pneumococcal infections.
Within the United States some Native American groups, like the Navajo and the White
Mountain Apache tribes, suffer from pneumococcal disease much more often than people in the
general US population. We don't know why pneumococcus disproportionately afflicts these
communities, but we know this health disparity can be significantly reduced through
vaccination. In 2000, for the first time a pneumococcal vaccine designed specifically for
infants, called PCV7, became available and was put into routine use among Navajo and Apache
as well as the general US population. PCV7 contains the 7 most common of the >90
pneumococcal strains that exist. Although PCV7 is only given to infants and toddlers, it
impacts pneumococcal disease throughout the community because it not only protects
vaccinated infants from disease it also protects them against NP colonization. Infants and
children are the main transmitters of pneumococcal colonization in the community so any
change in their carriage affects the whole population of pneumococcal germs circulating
within the family and community. Reductions in pneumococcal disease caused by the 7 types
in PCV7 have exceeded expectations, especially among Navajo and Apache where we have seen
virtually no cases in over 5 years. But, PCV7 has had the unintended consequence of
increasing the amount of pneumococcal disease from some pneumococcal types that are not in
PCV7. Therefore a new vaccine to protect against 13 pneumococcal strains, called PCV13, has
been developed and is about to be licensed and used (expected licensure Q4/2009). This
project aims to reveal the impact of PCV13 on pneumococcal disease and carriage of strains
which move from person to person within the Navajo community. We specifically intend to find
out if use of PCV13 has an effect on disease and carriage of the 6 additional strains in the
vaccine and to find out if PCV13 will result in the emergence of new pneumococcal serotypes
within the community, like PCV7 did. This information will allow us to design vaccine
strategies to meet these new patterns of pneumococcal disease and stay at least one step
ahead of the organism changes. It will also provide the evidence on which rational policies
for PCV13 use among Navajo can be made. This has been essential information in past
experiences of vaccine shortages, where Navajo communities were given priority for vaccine
use. We also propose to explore the correlations between pneumococcal colonization and
viral infection of the nasopharynx to establish if there is enhanced risk of pneumococcal
colonization in the setting of viral co-infection and if that enhances the risk of
developing disease. To achieve the overall objectives we propose pulling together three
types of information (1) effect of PCV13 on nasopharyngeal colonization with pneumococcus
and viral pathogens (2) effect of PCV13 on disease and (3) use of PCV13 in the community.

Inclusion Criteria:

- American Indian children and their families (i.e. people of all ages) who live in the
Whiteriver, Fort Defiance, Chinle, Gallup, Shiprock Service Units are eligible to
participate in the carriage portion of the study.

Exclusion Criteria:

- Anyone with a congenital anomaly of the nasopharynx would not be eligible to
participate in the carriage portion of the study