Kemp et al. (1997)

cohort

1,265 children born in 1977; followed through age 16 years (New Zealand)

DTP,* polio, measles by proxy

asthma, other allergic diseases by diary or questionnaire by proxy, and by medical records

Risk ratios for asthma episodes, asthma consults, and allergy consults for immunized children ages 0– 10 years were infinite (95% CI 1.03–infmity) because no events occurred in non-immunized group;

Risk ratios (95% CI), age 0.16 yrs; Asthma episodes: 2.9 (0.8-23.6) Asthma consults: 2.7 (0.7-22.3) Allergy consults: 5.6 (1.0-222.6)

Risk ratios for asthma episodes age 0–10 and measles vaccination: 1.0 (0.9-1.1)

weaknesses in study design include small number of unvaccinated children, marginal significance of results, potential for health care utilization bias; difficulty in adjusting for confounders (due to small number of unvaccinated)

weak evidence relevant to causality; favors no effect of any vaccine.