TABLE 2 Evidence Table: Controlled Epidemiological Studies—Vaccines and Heterologous Infections




Exposure Measure

Outcome Measure



Contributions to Causality

Kristensen et al. (2000)

Cohort; two visits required

8,752 children born to women participating in a longitudinal mortality study (Guinea-Bissau)

Vaccine status by inspection of immunization card. Vaccines included BCG, polio, diphtheria-tetanus-pertussis,* and measles vaccines

Mortality by parental report

RR (95% CI) mortality

Any vaccine = 0.74 (0.53–1.03)

BCG = 0.55 (0.36–0.85)

Measles = 0.48 (0.27–0.87)

DTP = 1.84 (1.10–3.10)

Polio = 1.81 (1.07–3.05)

vaccination status unclear; records not available for more than one-third; vaccinated children more likely to receive health care; maternal age differences in cohorts; adjustment for potential confounds not clear; DTP may negate the positive effect of BCG

weak evidence relevant to causality; favors beneficial effect of measles and BCG and negative effect of DTP in country with a high infant mortality of uncertain relevance to U.S.; BCG data not relevant to U.S.

Otto et al. (2000)

Randomized controlled trial comparing vaccinated and unvaccinated children

662 children born between Jan 1995 to Dec 1996 at a single hospital; 166 children excluded from final analysis (most missed vaccination) (Germany)

Vaccinated: 1st vaccination (diphtheria, pertussis,* tetanus, (ital.)Haemophil us influenzae type B, and poliomyelitis) 60 days after birth Unvaccinated: 1st vaccination at 90 days after birth

Any “Unspecific morbidity” from parental diary on days 66 to 90 after birth. Unspecific morbidity= coughing, signs of rhinitis, restlessness, vomiting, rash, pain, poor

Vomiting, cough, rhinitis, restlessness, rash, pain more common in unvaccinated group (all p<0.01); 4 hospitalizations in unvaccinated group vs. 1 in vaccinated group

Not blinded; drop out/exclusion rate 25%, disproportionately in early-vaccination group

Weak evidence relevant to causality; favors no effect or beneficial effect of vaccines

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