Bacille Calmette Guérin Immunisation at Birth and Childhood Morbidity in Danish Children.

To test that infants who get the BCG vaccine at birth experience 20% fewer hospitalisations in early childhood than non-BCG-immunised infants.

To test that infants who get the BCG vaccine at birth are prescribed less antibiotics during early childhood than non-BCG-immunised infants. Use of antibiotics was defined as one or more precriptions of systemic antibiotics (ATC groups J01, J02, J05, all subgroups inclusive).

To test if BCG vaccination within 7 days after birth influence the risk of atopic dermatitis defined by clinical examination at 13 months of age using "scoring atopic dermatitis (SCORAD)" or by parental report of physician diagnosed atopic dermatitis in the telephone interview at 13 months of age.

Number of participants with specific IgE (Phadiatop Infant) above the clinical cut-of level of 0.35.

To test that infants who get the BCG vaccine at birth respond in weight.The Z-score indicates the number of standard deviations away from the mean weight-for-age of the WHO anthropometric reference population (http://www.who.int/childgrowth/standards/en/). A Z-score of 0 is equal to the mean. Negative numbers indicate values lower than the mean and positive numbers indicate values higher than the mean.

To test that premature infants with gestational age less than 37 weeks who get the BCG vaccine at birth have unaffected psychomotor development measures: ASQ: Ages and stages questionnaire - a parent reported questionnaire that measures child psychomotor development. Total range of ASQ score: 0 to 300 points. Higher scores indicate higher level of psychomotor development.

To test that infants who get the BCG vaccine at birth has unaffected coverage with the subsequent 3rd diphtheria, tetanus, acellular pertussis, polio, Haemophilus influenzae type b (DTaP-IPV-Hib) vaccination scheduled to 12 months of age according to the Danish child vaccination programme. Since we did not expect all children to get their immunizations exactly at 12 months of age, the children were followed up until 13-months of age.

The Z-score indicates the number of standard deviations away from the mean weight-for-age of the WHO anthropometric reference population (http://www.who.int/childgrowth/standards/en/). A Z-score of 0 is equal to the mean. Negative numbers indicate values lower than the mean and positive numbers indicate values higher than the mean.

Number of participants diagnosed with episodic viral wheeze by a physician and treated with anti-asthmatic medicine according to the telephone interview.

Number of participants with food allergy diagnosed by a physician and mentioned in the telephone interview at 13 months of age

To test if infants who get the BCG vaccine at birth respond in length. The Z-score indicates the number of standard deviations away from the mean weight-for-age of the WHO anthropometric reference population (http://www.who.int/childgrowth/standards/en/). A Z-score of 0 is equal to the mean. Negative numbers indicate values lower than the mean and positive numbers indicate values higher than the mean.

To test if infants who get the BCG vaccine at birth respond in head circumference. The Z-score indicates the number of standard deviations away from the mean weight-for-age of the WHO anthropometric reference population (http://www.who.int/childgrowth/standards/en/). A Z-score of 0 is equal to the mean. Negative numbers indicate values lower than the mean and positive numbers indicate values higher than the mean.

To test that infants who receive the BCG at birth respond in thymic gland size defined by ultra sound examination. First, the thymus gland was identified in a horizontal scanning plane and the largest transverse diameter of the thymus was obtained. Second, in a sagittal scanning plane, the area of the largest lobe was assessed. Both measurements were obtained twice, and in case of more than 15% difference, both measurements were repeated. The mean of the two measurements were multiplied and defined as the thymic index.

To test if infants who receive the BCG at birth respond in leucocyte count (white blood cell count) measured as geometric mean (GM) cell concentrations (GM*10^9 cells/L).

To test if infants who receive the BCG at birth respond in monocyte count measured as geometric mean (GM) cell concentrations (GM*10^9 cells/L).

To test that infants who receive the BCG at birth respond in interferon-gamma response upon stimulation with BCG. The interferon gamma response was defined as a value above the cut-off value of 107 pg/ml.

To test the tetenus antibody response in BCG-vaccinated vs. non-BCG vaccinated children following routine immunisation against tetanus at 3, 5 and 12 months of age in blood samples obtained 13 months of age.

To test that Danish infants who get the BCG vaccine at birth experience less events of common cold until 13 months of age than non-BCG-immunised infants.

To test that Danish infants who get the BCG vaccine at birth get less pneumonia at 13 months of age than non-BCG-immunised infants.

To test that Danish infants who get the BCG vaccine at birth get less febrile episodes at 13 months of age than non-BCG-immunised infants.

To test that Danish infants who get the BCG vaccine at birth develop less episodes with diarrhoea and vomiting at 13 months of age than non-BCG-immunised infants.

To test that Danish infants who get the BCG vaccine at birth develop less acute otitis media at 13 months of age than non-BCG-immunised infants.

To test that Danish infants who get the BCG vaccine at birth develop less febrile convulsions at 13 months of age than non-BCG-immunised infants.

After parents having made the decision about whether to accept vaccination of their newborn through participation in The Danish Calmette Study, O'Connor's Decisional Conflict Scale was used to identify decisional conflicts. The score ranges from 0 (no decisional conflict) til 100 (maximum decisional conflict). Scores lower than 25 are associated with implementing decisions; scores exceeding 37.5 are associated with decision delay or feeling unsure about implementation; so a low score reflects a low level of doubt about the decision about participation/decline participation in the trial, and a high score reflects a high level of doubt.

To test that the use of telephone and internet was acceptable in the study population using the Quality of Informed Consent (QuIC) questionnaire. The questionnaire was divided into six categories; five on study comprehension and one on satisfaction with the information process. The items in the first five categories could be answered with "yes", "no" or "do not know". The last category was rated on a 7-point Likert scale, with 1 being "very dissatisfied" and 7 being "very satisfied". The primary outcome was the sum of the score for comprehension items and satisfaction items. Comprehension items were scored 1 point for each correct answer and 0 points for each incorrect answer. Satisfaction items were scored as rated on the 7-point Likert scale. Total score ranged from 7 to 69 points, comprehension score from 0 to 20 points and satisfaction score from 7 to 49 points. The higher score, the better comprehension and satisfaction.