[Comparative study of the efficacy of two types of BCG vaccines administered in different doses]. / Estudio comparativo de la eficacia de dos tipos de vacunas BCG administradas en dosis diferentes.

BACKGROUND: In 1993, WHO and UNICEF recommended the administration of 0.05 ml doses of BCG, instead of 0.1 ml, to newborns. This recommendation was adopted by the Chilean Ministry of Health, using the Mérieux vaccine. Subsequently, different Health Services detected a high percentage of children without BCG scar at the time of their growth and development control. AIM: To assess the efficacy of BCG vaccination in a double blind randomized fashion, using two vaccine types and different doses. PATIENTS AND METHODS: Newborns of two public hospitals of Santiago were randomly assigned to receive the Tokio or Mérieux BCG strains in doses of 0.05 or 0.1 ml. Ninety five to 125 days after vaccination, vaccine scar was measured and inmunogenicity was assessed using the tuberculin test. RESULTS: Six hundred newborns (150 in each group) were included in the protocol and results were assessed in 408. The percentage of children with a PPD reaction of 0 mm was 9.3, 3.7, 7.8 and 0% with the Mérieux vaccine in doses of 0.1 ml, Tokio vaccines in doses of 0.1 ml, Mérieux vaccine in doses of 0.05 ml and Tokio vaccine in doses of 0.05 ml, respectively. In the same groups the scar diameters were 6.4 +/- 3.4, 7.3 +/- 2.7, 5.6 +/- 2.8 and 7.3 +/- 2.9 mm. The observed differences for each group are significant, depending on the type of strain and dose, but favoring the Tokio type of vaccine. CONCLUSIONS: The BCG scar diameters obtained in this study are similar to those obtained in previous works in 1984 and 1986. This scar is the evidence of vaccination that nurses detect in health controls. Therefore the use of 0.1 doses for vaccination, that result in better scars and PPD response, is recommended.

The influence of BCG immunization on tuberculin reactivity in healthy Chilean women in the third trimester of pregnancy.

SETTING: Tuberculin testing is an accepted method for screening pregnant women for tuberculosis. The interpretation of tuberculin reactivity in bacillus Calmette-Guerin (BCG)-immunized pregnant women is still in debate. OBJECTIVE: Four related issues were addressed: (1) The effect of pregnancy on tuberculin reactivity; (2) the effect of age differential on tuberculin reactivity; (3) the effect of repeated immunization with BCG; and (4) the risk of developing tuberculosis during pregnancy or a 3-year post-partum period. DESIGN: We performed tuberculin testing in 840 healthy Chilean women in the 32nd to 34th week of pregnancy; 807 had been immunized with 1 or more doses of BCG. There were 3 age groups: 177 were < or = 19 years old, 534 were 20-29 years old, and 129 were > or = 30 years old. All women in the study were followed at least 3 years post-partum. RESULTS: Women < or = 19 years old and non-pregnant women of similar age studied in the same geographical area had a similar distribution of the size of tuberculin reactions. Over 50% of all BCG-immunized women in each group had tuberculin reactions > or = 10 mm. A differential effect of different doses of BCG was significant only in 20- to 29-year-old women. None of the women in this study developed tuberculosis during pregnancy or a 3-year post-partum observation period. CONCLUSIONS: Healthy, BCG-immunized pregnant women may have positive tuberculin reactions without having an increased risk for tuberculosis. The incidence of tuberculosis and the BCG immunization status need to be considered in the development of policy recommendations for diagnosis and treatment of Mycobacterium tuberculosis infection in pregnant women.

Repeated tuberculin testing in patients with active pulmonary tuberculosis.

OBJECTIVE: The proportion of tuberculin reactors in a population and the intensity of tuberculin reactions have been shown to increase with increasing exposure to mycobacterial infection, eg, repeated BCG immunization. These observations suggested that tuberculin reactivity would become uniformly high in individuals with a high mycobacterial load who did not have a known cause of anergy. Since tuberculin reactivity has been measured to evaluate the possible genetic regulation of responses to mycobacteria in humans, it is important to study its behavior under conditions of ongoing, maximal exposure to mycobacteria. In the present study, we determined the mean size of tuberculin reactivity in BCG-immunized and unimmunized patients with pulmonary tuberculosis of recent onset, and the stability of tuberculin reactions during and after treatment of pulmonary tuberculosis. METHOD: Serial tuberculin testing was performed on patients with newly diagnosed active pulmonary tuberculosis diagnosed over a period of 2 years at the National Institute for Respiratory Diseases in Santiago, Chile. The first tuberculin test was performed at the time of diagnosis in 58 patients. Repeated tuberculin testing was performed 2 weeks later in 15 patients with initial reaction sizes < 15 mm. Four additional tuberculin tests were performed, one each at 3-months intervals in 42 patients regardless of the size of the initial tuberculin reaction. RESULTS: Tuberculin reactions at entry had a unimodal distribution in patients both with and without BCG scars (14.8 +/- 5.0 mm and 16.5 +/- 5.2 mm, respectively). A second tuberculin test in patients with initial reaction sizes < 15 mm showed a moderate, statistically significant increase in the mean reaction size (PPD1: 10.1 +/- 3.2 mm; PPD2: 11.9 +/- 4.8 mm). Repeated tuberculin testing over 1 year revealed no significant changes in reaction size. The mean reaction sizes were 15.8 +/- 5.0 mm at entry, 15.5 +/- 5.4 mm at 3 months, 17.2 +/- 5.2 mm at 6 months, 17.0 +/- 5.1 mm at 9 months, and 16.7 +/- 54 mm at 12 months. The standard deviation of a random observation within patients was 5.3 mm. The largest variations due to increased reactivity after 6 months of treatment were observed in patients with reaction < 15 mm at entry compared with hyperergic patients, and in BCG-immunized patients compared to unimmunized patients. CONCLUSIONS: In the presence of an ongoing mycobacterial infection, patients without anergizing conditions express a tuberculin reactivity that is relatively constant during and after treatment of pulmonary tuberculosis. The size and stability of the reactions seem to be determined by individual conditions that include the tuberculin reactivity at the time of diagnosis and the BCG immunization status.

[Compliance with tuberculosis treatment in adults in Santiago, Chile]. / Adherencia al tratamiento de la tuberculosis del adulto en Santiago, Chile.

A prospective study was conducted to estimate the current magnitude of adherence to short-course tuberculosis treatment, the degree of abandonment, the characteristics of treatment dropouts, and the causes of this abandonment. The study group was made up of tuberculosis patients over the age of 15 who received care at the Western and Southern Health Services of the Metropolitan Region of Santiago, Chile, between 1 October 1987 and 31 January 1988. The percentage abandoning treatment, calculated by the life table method, was 11.5. The profile of patients who dropped out of treatment was as follows: male, under 45 years of age, single, low level of education, no steady work, homeless, and alcoholic. In addition, an opinion survey on the variables associated with abandonment was conducted and it was concluded that the main ones were alcoholism and intolerance to tuberculosis drugs. Awareness of this profile makes it possible to take measures to prevent patients from abandoning treatment, as well as to educate and even hospitalize at the start of treatment those tuberculous patients exhibiting such a profile.

The influence of Calmette-Guérin bacillus immunization on the booster effect of tuberculin testing in healthy young adults.

The booster or enhancement effect of repeated tuberculin skin testing in Calmette-Guérin bacillus (BCG)-vaccinated young adults was studied in 208 first-year medical, nursing, and medical technology students in Santiago, Chile, where BCG vaccine is usually administered at birth and at 6 and 14 yr of age. Thirty-three students had no BCG scar, 62 had one scar, 71 had two scars, and 42 had three scars. The mean age for each group was 19 yr. All students were healthy and had no known exposure to tuberculosis or history of tuberculosis or other mycobacterioses. The size in millimeters of induration of the first tuberculin reaction (PPD1) was clearly correlated with the number of BCG scars: 2.3 +/- 4.6 for no scars; 6.7 +/- 6.7 for one scar; 10.9 +/- 5.9 for two scars, and 13.2 +/- 5.3 for three scars. The second tuberculin reaction (PPD2), performed 2 wk later on the contralateral forearm, showed a marked increase in reactivity. The increase in reaction size was most evident in students who had BCG scars but who were initially PPD negative (less than 10 mm). Smaller increases were observed in students without BCG scars, and also in those who had BCG scars but who were initially tuberculin positive (greater than or equal to 10 mm). The persistence of the booster effect was evaluated by performing PPD3 1 yr later. PPD1-negative students with BCG scars maintained the increased level of reactivity to PPD2 after 1 yr. An immunizing effect of tuberculin testing was suggested in 11 nonimmunized students who were initially PPD negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Booster effect of tuberculin testing in healthy 6-year-old school children vaccinated with Bacillus Calmette-Guérin at birth in Santiago, Chile.

In order to determine whether tuberculin testing caused a booster effect in children vaccinated with Bacillus Calmette-Guérin (BCG) at birth, we studied forty 6-year-olds by repeat tuberculin testing 2 weeks later on the contralateral forearm. All children were healthy and had no known exposure to tuberculosis. None of the children had a history of mycobacteriosis other than tuberculosis. The mean induration was 2.3 +/- 1.8 mm for the first tuberculin reaction and 7.6 +/- 3.3 mm for the second tuberculin reaction (P less than 0.005). Four children had positive reactions (greater than or equal to 10 mm) to the first purified protein derivative test; 18 children were positive upon retesting. Eleven of these latter children had increases of at least 6 mm from reactions less than 10 mm to greater than or equal to 10 mm. The size of the BCG scar was significantly correlated to the size of both the first and second purified protein derivative reactions (P less than 0.01), suggesting that the increased reactivity upon retesting was a consequence of sensitization induced by BCG vaccination 6 years earlier. All children remained healthy after this study was completed. Retesting of tuberculin reactivity within 2 weeks in BCG-vaccinated children with reactions less than 10 mm will produce reactions greater than 10 mm in some healthy children who may not require antituberculosis treatment.

Reaccion tuberculinica y cicatriz en lactantes vacunados com BCG liofilizado. / Tuberculin reaction and scar in infants vaccined with lyophilized BCG

Se realiza un trabajo de campo en 80 ninos de 4 meses, vacunados en el periodo de recien nacido, con vacuna BCG liofilizada, importada de Canada y sometida a control de calidad por el Instituto de Salud Publica de Chile. Las caracteristicas mas relevantes de esta vacuna consisten en cicatriz semejante a las utilizadas en Chile anteriormente; reaccion tuberculinica significativamente menor (media 5,5 mm DS 3,51 p < 0,01) que la obtenida en un estudio efectuado en 1976 en ninos de similares caracteristicas, vacunados con BCG liquido; falta de correlacion entre la reaccion tuberculinica y el tamano de la cicatriz BCG

Use of the bifurcated needle for BCG vaccination of newborns.

The bifurcated needle vaccination method used successfully against smallpox is a relatively simple technique that can be administered by personnel with only basic preparation and a minimum of training. This fact suggests that it could prove useful in campaigns of BCG vaccination against tuberculosis--especially for vaccination of newborns. With this end in mind, two studies were carried out in Santiago, Chile, to examine previously reported difficulties with the method and to assess its potential as an alternative to the best current method, that of intradermal inoculation. These studies indicated that previously reported variations in the results achieved by different vaccinators could be markedly reduced. However, they also found that the bifurcated needle method did not cause a sufficiently large dose of vaccine to enter the subject--even when fifteen needle strokes and a highly concentrated vaccine (160 mg per ml) were employed. It was thus concluded that although modification of the needle or other changes might ultimately yield satisfactory results, the bifurcated needle technique cannot yet be recommended for BCG vaccination of newborns.

Use of the bifurcated needle for BCG vaccination of newborns

The bifurcated needle vaccination method used successfully against smallpox is a relatively simple technique that can be administered by personnel with only basic preparation and a minimum of training. This fact suggests that it could prove useful in campaigns of BCG vaccination against tuberculosis--especially for vaccination of newborns. With this end in mind, two studies were carried out in Santiago, Chile, to examine previously reported difficulties with the method and to assess its potential as an alternative to the best current method, that of intradermal inoculation. These studies indicated that previously reported variations in the results achieved by different vaccinators could be markedly reduced. However, they also found that the bifurcated needle method did not cause a sufficiently large dose of vaccine to enter the subject--even when fifteen needle strokes and a highly concentrated vaccine (160 mg per ml) were employed. It was thus concluded that although modification of the needle or other changes might ultimately yield satisfactory results, the bifurcated needle technique cannot yet be recommended for BCG vaccination of newborns (Au)