Overall, filibustering and U.S. policies seem to have hindered more than helped U.S. attempts at territorial expansion in this time period. The Gadsden Purchase was the only official territorial acquisition during the 1850s.
Acellular pertussis vaccines were introduced nation-wide in Sweden in 1996, 17 years after the withdrawal of whole-cell pertussis vaccine from the childhood immunisation schedule.he annual incidence of culture-confirmed B. pertussis was 89-150 per 100,000 before introduction of acellular pertussis vaccines and has dropped to 17-26 per 100,000. The data suggest that unimmunised infants and children who have received only one dose of pertussis vaccine were provided some protection.
Immunization against pertussis is included on the U.S. childhood immunization schedule as part of the combined DTaP (diphtheria, tetanus, and pertussis) shot. This vaccine is given in several doses, with the first recommended at two months of age, and the last between age four and six years.elgian scientists Jules Bordet (1870-1961) and Octave Gengou (1875-1957) isolated the bacterium Bordetella pertussis, the causative agent of pertussis (whooping cough), which they had first observed in 1900. It would later also come to be known as the Bordet-Gengou bacillus.