Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children. Glanz JM, McClure DL, Magid DJ, et al. Pediatrics 2009; 123 (): 1446-51.
Explanatory Note: Vaccines protect the individual against diseases but also, when many are immunized, they can protect those who cannot be immunized (this is called community immunity).
With the successful use of vaccines, many formerly common diseases are now infrequently seen in our communities. Mistakenly believing that their children are not at risk of these diseases, some parents concerns have shifted from fear of the diseases to fears about vaccine safety. Some of these parents refuse (or delay) some vaccines for their children. Unfortuantely, the number of these families has increased in recent years.
Are children of parents who refuse pertussis vaccine at greater risk of developing pertussis (whooping cough)?
This case-control study included children receiving care in a Denver, Colorado managed care organization.
Researchers identified all pediatric cases of laboratory confirmed whooping cough between 1996 and 2007. They compared each case of pertussis to 4 randomly selected control children who were matched by gender and the age for when pertussis had occurred.
They reviewed the children’s medical records to confirm the laboratory diagnosis of pertussis and their immunization histories. Children were classified as “vaccine refusers” if that was recorded in the chart or they were classified as “vaccine acceptors” if they were immunized or if the reason for lack of vaccination was not vaccine refusal (for example, if vaccine was not given because the child was ill). The study analyzed the results for all the children and also for just those who were continuously enrolled from 2-20 months of age.
The study identified 165 verified pediatric cases of pertussis and 624 controls. Nine cases and 29 controls were excluded from analysis because the reason for their lack of immunization was not documented. Among the 27,748 continuously enrolled children, there were 31 cases of pertussis and 308 controls who were 2-20 months of age.
The study found that in both groups, vaccine refusal was strongly associated with pertussis infection. Children whose parents refused pertussis immunization were 23 times more likely to develop pertussis than those whose parents accepted vaccines.
The study demonstrated a strong association between vaccine refusal and the risk of developing pertussis in children.
Despite high immunization levels in the community, community (herd) immunity did not protect unimmunized children from developing pertussis. Parents who refuse immunizations for their children need to be aware that their children are at increased risk of vaccine preventable diseases and that they place other children at risk as well.