the seroepidemiological study carried out on a random sample of pregnant females aged between 15 and 45 in catalonia ( spain ) showed that the prevalence of antibodies found in the survey ( 97.5 +/- 2 ) varies from that shown by studies performed in continental areas of europe and north america in the pre-vaccination era ( 80-90 % ) and is similar to that currently found in certain continental areas of asia and africa ( about 95 % ) where the prevalence of the virus seems to be very high , and in certain industrialized countries which have implemented effective vaccination programmes ( 95-97 % ) .
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africa
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