University of OtagoWednesday 26 October 2011, 1:32PM
Media release from University of Otago
Immunising children may protect whole African villages from
Vaccinating young children in Africa against pneumococcus may help
protect their entire communities from deadly infections this
bacterium can cause, a new study co-authored by a University of
Otago researcher suggests.
Invasive pneumococcal disease can strike all ages but takes its
grimmest toll on the young, annually killing an estimated 800,000
children under-five worldwide through illnesses such as pneumonia,
blood infection and meningitis.
In a randomised controlled trial involving 21 villages in rural
Gambia, researchers showed that vaccinating young children reduced
nasal carriage of the types of pneumococcal bacterium that the
PCV-7 vaccine targeted; not only in the vaccinated children, but
also in vaccinated and non-vaccinated older children and adults.
Otago's Professor Philip Hill led the field aspects of the study
before taking up his position at the University.
Professor Hill, Director of the University's Centre for
International Health, says that previously there were concerns that
achieving this kind of 'herd effect' through immunising infants
against pneumococcus would be much more difficult in Africa than in
"We have now shown for the first time that, despite the greater
prevalence of pneumococcal carriage and a high level of infection
transmission compared to other parts of the world, it may be
feasible to protect entire communities in Africa from pneumococcal
disease through vaccinating young children alone," he says.
The study, which appears in this week's issue of PLoS Medicine,
also showed that vaccinating whole communities did not result in a
community-wide increase in carriage of non-vaccine serotype
pneumococci - other types of pneumococci that are not included in
the vaccine - in the two-year period after vaccination.
"This is an encouraging finding, as the fear always is that
non-vaccine pneumococci types will rush in to replace those to
which people are now immune. This would lead to reduced benefits
from what is an expensive vaccination programme for a low-income
Professor Hill and colleagues at the Medical Research Council (MRC)
Unit in The Gambia will continue to study the effectiveness of
PCV-7 vaccine and other newer vaccines which target a wider range
of pneumococci types. Recently the Unit was awarded a US $7M grant
over four years from the Bill & Melinda Gates Foundation to
support this work in rural Gambia.
The PLoS Medicine study was led by researchers from the MRC Unit in
collaboration with the London School of Hygiene & Tropical
Medicine. A copy of the paper is available at this website:
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