The number of polio cases in 2007 declined in Afghanistan and
Pakistan, two of the last countries where transmission has never been
interrupted. But security and operational problems remain significant
barriers to stopping transmission, according to a recent report by the
international polio eradication partnership.
The March 28 issue of Morbidity and Mortality Weekly Report from
the U.S. Centers for Disease Control and Prevention reports that
Afghanistan had 17 cases in 2007, down from 31 in 2006. Pakistan had 32
polio cases in 2007, compared to 40 in 2006.
Polio transmission continued in regions where significant numbers of
children were not fully vaccinated. These regions include remote border
areas of both countries, where security concerns have hampered
vaccination efforts. In a breakthrough in August 2007, anti-government
forces in Afghanistan agreed to support vaccination campaigns.
Security was not the only factor contributing to the spread of polio
in Pakistan, though. Vaccination campaigns in some relatively secure
southern districts also missed significant numbers of children and had
several polio cases as a result.
Most of the 2007 vaccination campaigns targeted the more virulent
type 1 virus with monovalent vaccine, alone or in addition to trivalent
vaccine. The proportion of cases caused by type 1 virus declined in
Afghanistan between 2006 and 2007, from 94 percent to 35 percent, but
increased slightly in Pakistan, from 50 percent to 59 percent.
The report described progress against polio as “limited,” and said
improvements in security, as well as the quality of vaccination
campaigns in secure areas, will be needed to eradicate the disease.
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