Zimbabwe: from 40% unvaccinated to 4%

According to the UN (as of May), the percentage of Zimbabwean children who are vaccinated is less than 60%.  Unicef requested $17M to vaccinate as well as attend to cholera and typhoid outbreaks [full report here].  A more recent link claims the measles campaign cost $8M, with the goal of vaccinating all children nationwide.  If you saw the Malawi post the other day, with mortality numbers in it, you’ll recall that Zimbabwe’s child mortality for measles in the last year is hovering around 6% (19th century England was as high in the worst cases as 10%, so 6% is a pretty scary number).

Now that the campaign is over, WHO is claiming a 96%* measles vaccine coverage for the country — pretty impressive, considering in May they were at less than 60%.


* for the curious among you, here are the provinces:

  • Manicaland 101%
  • MashCentral 91%
  • MashEast 98%
  • MashWest 97%
  • MatNorth 90%
  • MatSouth 93%
  • Midlands 96%
  • Masvingo 101%
  • Bulawayo 83%
  • Chitungwiza 97%
  • Harare 97%
  • National 96%

5,106,648 children had been vaccinated against measles [Populations on the ground were higher in some areas than those projected by the Central Statistics Office; each district was given a 5% buffer stock of vaccines that sufficed]; 1,667,547 of those were in the six months to five-year-old category, which is most vulnerable to measles, and 3,439,101 between five and 15 years. Some 1,616,133 children also received Vitamin A supplements. See the graph above for district coverages.

You may also note some of the districts report more than 100% coverage.  Obviously this is impossible, you cannot vaccinate more than 100% of the children, at least in the straight-forward sense of common logic.  The Centers for Disease Control (“CDC”) explain the reporting of 100% coverage in their September 2009 edition of the Morbidity and Mortality Weekly Report (“MMWR”):

SIA coverage usually is estimated by an administrative method relying on the reported number of vaccine doses administered and available target population denominator data, both of which often are imprecise. For example, during 2001–2008, several countries reported vaccinating >100% of children targets in SIAs. Improved methods for determining the actual target population size for SIAs are needed; reported coverage also should be routinely validated by independent surveys.

Basically the target number of children is estimated from models in some cases, and more children may actually exist than estimated.  Also, the number of vaccines administered is not as precise as we would like it to be.  There are also possibly other factors at work, depending on what agencies (various ministries of health) are involved, and thus the call for “independent surveys.”

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