A comparative analytical sample survey regarding the coincidence of data found in Vaccination Record Cards (yellow ones) belonging to children and those (blue ones) belonging to the local Health Units’ archives conducted in 16 counties with populations over thirty thousand among those pertaining to the Campinas Administrative Region (83 counties with a total population of 2.3 million) of the State of S. Paulo, Brazil, was here described showing that in 788 cards effectively examined there were 2,307 diverging vaccine informations. […]