Since measles was declared eliminated in the United States after January 1, 2000, there have been 18 published measles studies and more than half had no history of measles vaccination. Of the 970 measles cases, 574 cases were unvaccinated despite being vaccine eligible and 405 had nonmedical exemptions (for religious or philosophical reasons). Among the 32 reports of pertussis outbreaks, which included 10,609 individuals ranging in age from 10 days to 87 years. However, several pertussis outbreaks also occurred in highly vaccinated populations, indicating waning immunity. A substantial proportion of the US measles cases were intentionally unvaccinated. Although pertussis resurgence has been attributed to waning immunity and other factors, vaccine refusal was still associated with an increased risk for
Since measles was declared eliminated in the United States after January 1, 2000, there have been 18 published measles studies and more than half had no history of measles vaccination. Of the 970 measles cases, 574 cases were unvaccinated despite being vaccine eligible and 405 had nonmedical exemptions (for religious or philosophical reasons). Among the 32 reports of pertussis outbreaks, which included 10,609 individuals ranging in age from 10 days to 87 years. However, several pertussis outbreaks also occurred in highly vaccinated populations, indicating waning immunity. A substantial proportion of the US measles cases were intentionally unvaccinated. Although pertussis resurgence has been attributed to waning immunity and other factors, vaccine refusal was still associated with an increased risk for