Importance of attributable risk in monitoring adverse events after immunization: hepatitis B vaccination in children.
OBJECTIVE
Most vaccine safety data present only the postvaccination incidence of all adverse events rather than an estimate of attributable risk. This study sought to illustrate the difference between the 2 estimates with data from a hepatitis B immunization program.


METHODS
The incidence of health problems occurring before and after each dose of hepatitis B vaccine in a cohort of 1130 children were compared.


RESULTS
Although 47.5% of all children reported an adverse event during the 4 weeks following each of the 3 doses, adverse events attributable to immunization occurred in only 10.6% of children.


CONCLUSIONS
Postimmunization incidence systematically overestimates the risk of adverse events. Estimating actual attributable risk is necessary to avoid false beliefs regarding immunization.
De Serres
G
G
Institut national de santé publique du Québec, Québec Canada. gdeserres@cspq.qc.ca
Duval
B
B
Boulianne
N
N
Rochette
M
M
Dionne
M
M
Fradet
M D
MD
Massé
R
R
D016907:Adverse Drug Reaction Reporting Systems; D015982:Bias; D002648:Child; D003627:Data Interpretation, Statistical; D004342:Drug Hypersensitivity / Q000453:epidemiology / Q000209:etiology; D016903:Drug Monitoring / Q000379:methods*; D005334:Fever / Q000139:chemically induced / Q000453:epidemiology; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000139:chemically induced / Q000453:epidemiology; D006261:Headache / Q000139:chemically induced / Q000453:epidemiology; D017325:Hepatitis B Vaccines / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D011792:Quebec / Q000453:epidemiology; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000453:epidemiology; D012307:Risk Factors; D014504:Urban Health / Q000706:statistics & numerical data; D014614:Vaccines, Synthetic / Q000009:adverse effects*
C075654:Engerix-B; D017325:Hepatitis B Vaccines; D014614:Vaccines, Synthetic