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.
The DTaP vaccine prevents the spread of diphtheria, tetanus and pertussis from an infected or exposed person to another person. The Federal Drug Administration introduced the DTaP vaccine in 1997 to replace the DTP vaccine formula, which was linked to safety concerns in young children. Similar to other childhood immunizations, DTaP side effects are minimal when compared to the risks of contracting one of the three diseases it protects against.