A study was published in Pediatrics 2009; 123:1446-51 that showed childern whose parents refused the pertussis vaccine were 23 times more likely to contract the disease than children whose parents allowed the vaccine. The study was done by Jason M. Glanz PhD. It was conducted in Colorado. Dr. Glanz is part of the Kaiser Permanente Colorado Institute for Health Research. The study examined pertussis vaccination rates and disease prevalence in children age 2 years to 18 years between 1996 and 2007. The common name of this disease is whooping cough. The causitive agent was first isolated in 1906 by Bordet and Gengou and the scientific name is Bordetella pertussis. Naturally acquired disease is known only in humans, although experimental infections have been produced in other animals. The disease begins in children after an average incubation period of 10 days with cold like symptoms. After 10-14 days the lower respiratory tract becomes involved and paroxysms of severe coughing develops accompanied by the characteristic Whooping sound made during inspiration. Secondary bronchopneumonia is common and obstruction of the bronchi by mucous plugs may cause severe lack of oxygen resulting in convulsions. In nonfatal cases the paroxysmal stage lasts approximately 2 weeks and is followed by continued cough for another 2-3 weeks. Encephalititis occasionally occurs late. The mortality rate is the highest in infants. The severe form in infants can be treated with antibiotics, penicillin is not effective. It occurs throughout the world and is estimated that more than 9 out of 10 persons acquire the disease. It is highly contagious and epidemics occur in the U. S. in prevaccination era every 2-4 years. Among nonimmunized children the attack rate is nearly 90%. The mortality rate for the disease fell markedly in the period from 1920 to 1950, its incidence fell began to fall only after vaccinations began in the 1940's. 72% of babies under 6 months that get the disease have to be hospitalized. 1 out of 10 get pneumonia. 1 out 250 get encephalititis. 1 out of 50 have seizures. 84% of the deaths occur in children under 6 months. The lesson is clear vaccination is preventative and life saving.