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.
Pertussis vaccines are recommended for people of all ages. Babies and children should get 5 doses of DTaP for maximum protection. A dose is given at 2, 4 and 6 months, at 15 through 18 months, and again at 4 through 6 years. A booster dose of Tdap is given to preteens at 11 or 12 years old.ertussis, or whooping cough, can be prevented with vaccines. Before pertussis vaccines became widely available in the 1940s, about 200,000 children got sick with it each year in the United States and about 9,000 died as a result of the infection.