Search

Inspection of 300 infants attending a primary health care (PHC) center at Hail region showed that 18.8% of children failed to develop BCG reations. This directed attention to inspect the process of vaccination at hospitals in which 80% of deliveries and BCG vaccination took place. Defects in the process of vaccination and cold chain system were noticed. Reorganization of the process of vaccination in addition to training the staff responsible for vaccination were done. A survey was followed to evaluate failure of BCG vaccination before and after the intervention. We checked 4145 infants two to twelve months of age, for any reaction at the site of BCG vaccination. After intervention vaccination failure dropped from 20.4% to 4.9% for infants vaccinated in hospitals (p = 0.00001), and from 7.9% to 3.2% for those vaccinated in health centers (p = 0.01). Moreover, before intervention success of BCG vaccination was significantly higher in PHC centers (92.1%) than in hospitals (79.6%). This difference became insignificant after intervention because success of BCG vaccination in hospitals has increased up to 95.1% compared to 96.8% in health centers. Inspection of all infants for BCG reaction is continued as a part of routine work at PHC centers, and re-vaccination of those who failed to develop reation to BCG is conducted without any reported complications.

Three freeze-dried BCG vaccines: Polish, Danish and Japan were compared. It was found, that they fullfill all WHO requirements for freeze-dried BCG vaccine. They were shown to have a high survival of bacilli upon freeze-drying, good viability, thermostability and allergizing properties in guinea pigs. Japan BCG vaccine had especially high viability and thermostability. Mentioned BCG vaccines were safe for guinea pigs even in dose of 5 mg BCG (100 human doses) administrated subcutaneously. It was shown, that Polish BCG vaccine, that is regarded as vaccine of middle strength does not differ essentialy from strong Danish vaccine in respect to viability, thermostability and allergizing properties in guinea pigs evaluated 6 weeks after vaccination.

Tuberculosis (TB) is a disease caused by a mycobacterium, whose incidence has increased in the past years. This increase is related to the adquired immunodeficiency syndrome (AIDS). Due to its high prevalence, Spain is considered a developing country. The tuberculous infection depends on the degree of functionality of the alveolar macrophages that stimulate the lymphocytes and isolate the bacillus. The infection by mycobacterias can be quantified by means of the cutaneous reaction against tuberculin and mantoux, allowing us to select the subjects that must receive prophylaxis. For its correct interpretation, it is currently recommended to avoid BCG vaccination of children, except in countries with high prevalence of TB.

Two surveys were carried out to audit the Avon Neonatal BCG Immunization Policy. The aim of the audit was to determine whether children with indications for neonatal BCG immunization had received the vaccine before attendance at routine six-week postnatal examination. In the first survey, 15 of 359 (4.2 per cent) infants were identified as eligible for BCG, of whom only two (13.3 per cent) had received it. These findings were discussed with the medical and nursing staff involved in the care of the infants in Avon, and action was taken to improve compliance with the policy. The survey was then repeated to complete the loop of the audit cycle and to observe whether the action taken had the desired effect. Forty of 644 (6.2 per cent) infants were identified as being eligible for BCG immunization in the repeat survey, of whom 32 (80 per cent) had received it. There was a statistically significant difference in results between the first and the second survey (p < 0.0001). It is concluded that completion of the audit cycle can markedly improve clinical practice.

The BCG vaccine has been used to prevent tuberculosis since 1921 and applied for immunostimulation in neoplasia since the 1960s. Both the preventive and immunostimulation effects have been evaluated and communicated with contradictory, positive and negative conclusions. For an objective evaluation and interpretation of the protective efficacy, effectiveness and efficiency of the BCG vaccination it must be considered that: (1) several BCG substrains have been developed in manufacturing laboratories that differ in the residual virulence which determines immunogenicity and reactogenicity; (2) various liquid and freeze-dried BCG vaccine production methods are used, resulting in different BCG viable units per dose; (3) quantitative bioassay methods are not yet being used for statistical quality control of the vaccine; (4) BCG products are applied in various demographical, epidemiological and socioeconomic conditions with different vaccination policies; (5) inadequate biostatistical models are often used to analyse efficacy, effectiveness and adverse reactions. The same conditions influence the precise evaluation of BCG immunostimulation in neoplasia. Recombinant DNA technology will modify production methods, and explain at the molecular level the mechanism of the protective effects BCG confers in tuberculosis and immunostimulation in neoplasia. High level laboratory techniques and biostatistical methods, based on probability logic and inductive inference, ensure appropriate experimental designs and the exact analysis of laboratory data and the results of vaccination policies. They will lead to the evaluation of the protective effect of BCG in order to reduce the BCG contradictions.

The manufacture of Therapeutic BCG can and should be a controlled process, to ensure adequate treatment doses are received by CIS patients. Standardization of production methods and CFU potency testing methods are essential to ensure continued successful treatment of CIS. Stability data can be used to validate assumptions about Therapeutic BCG potency used in clinical trials. Accelerated heat degradation studies of Therapeutic BCG should not be used for predictions of shelf life, but can be used for comparative purposes.

The protective and immunostimulating effect of the living attenuated BCG vaccine cannot be expressed by bacterial mass (mg/dose). Colony forming units (CFU 10(6)/ml) and 95% confidence limit estimates as precise in vitro potency tests are required for the exact evaluation of the immunogenicity and reactogenicity of the BCG vaccine. The laboratory technique and computerized statistical analysis presented here ensure the precision and validity of the BCG viability test, permit the standardized BCG CFU 10(6)/ml unbiased point and confidence interval estimation for preventive and immunomodulator administration of the BCG vaccines and the evaluation of the genetic transformation frequency in recombinant BCG experiments.

Specific active immunotherapy for melanoma has been administered to several thousand patients since 1972, using an irradiated whole-cell preparation. A humoral response to vaccination can be demonstrated in a large percentage of patients. This response increases while immunizations are continued and decreases after cessation of therapy. The vaccinations are well tolerated; however, the therapeutic impact of this whole-cell vaccine awaits a randomized trial for definitive evaluation.

Objective: To evaluate the need for the BCG revaccination programme of schoolchildren in Finland., Design: Investigating tuberculin sensitivity using the standard WHO Mantoux test and developing a model to estimate the risk of discontinuation, assuming that the annual incidence of tuberculosis within ten years after revaccination will remain at its present level; that the revaccination rate will be 2, 6 or 20%; and that the degree of protection will be 10, 20, 40 or 80%., Setting and Participants: Urban and rural schoolchildren--3,346 vaccinated with Copenhagen and 655 with Glaxo BCG vaccine at birth., Results of Data Analysis: The annual incidence of tuberculosis was 4.2 per 100,000 in the age-group 15-24 years. BCG revaccination was given formerly to 20% of the age cohort but nowadays only 6% or 2% meet the criteria after receiving either Copenhagen or Glaxo BCG at birth. After discontinuation the expected increase of tuberculosis in the age-group 15-24 years is predicted to fall within the limits of 0.1-24 cases per year. If 2% are left without revaccination the increase will be 0.1-2.4 cases., Conclusions: Due to the low annual incidence of tuberculosis in adolescents and to the small risk of increase the BCG revaccination programme has been discontinued from 1990 onwards.

BCG is the only vaccine for tuberculosis and leprosy known to be effective in at least some places. Unfortunately it tends to be less successful in just those areas of the developing world where a vaccine is most needed. Although molecular biology offers the prospect of alternatives, these still lie in the indefinite future, and the best use has to be made of BCG. A number of preparations are available from different manufacturers, and a vaccine should be selected with good evidence of efficacy, and a low incidence of complications. Selection of the optimal age for administering BCG should be based on factors pertaining in the area where it is to be used. The influence of contact with environmental mycobacteria, the age at which mycobacterial diseases occur, and the logistics of vaccine delivery must be taken into account. The addition of a suspension of killed Mycobacterium vaccae to BCG may increase its efficacy. Skin test data show that recognition of antigens common to all mycobacterial species and thought to be the first step in the protective immune response, is significantly enhanced by the additive. M. vaccae also contains a substance, or substances, "switching off" the tissue destructive aspect of the Koch phenomenon that is part of the immunopathology of tuberculosis. A suspension of killed M. vaccae alone can be used to enhance immune responses of persons unsuitable for BCG vaccination, such as those already tuberculin positive, and those with scars of earlier BCG vaccination.

In 1956 a programme was initiated to vaccinate all children aged 12-14 years who were attending schools in Queensland, Australia. In view of the declining incidence of tuberculosis in Australia as a whole, there was a need to evaluate the effectiveness of the programme and its procedures. We therefore carried out a case-control study of Queensland's population, excluding certain known high-risk groups. Cases were Queensland residents with notified tuberculosis and of the appropriate age; two controls per case were chosen from the electoral roll. Information on vaccination status was obtained mainly from questionnaires and school records, where available. The results show that at best BCG vaccination had a modest protective effect, approximately 30% when the patients were diagnosed, which was on average 15 years after they had been vaccinated in the school programme. In the north the climate of Queensland is tropical, while in the more heavily populated south it is subtropical. A substantial proportion of the school records reported weak positive reactions to preliminary tuberculin testing, believed to be due largely to atypical mycobacteria. A similar phenomenon has been observed in other tropical regions, and may help to explain the apparent absence of a strongly protective effect for BCG vaccination.

The degree of thermal degradation of BCG vaccines prepared from various substrains, using a test evaluating number of viable particles of BCG was determined. Thermal degradation coefficient were established for particular vaccines in different temperatures and a prognosis time curve of 50% CFU titer loss was constructed. It was found, that polish vaccine does not differ essentially from danish and french vaccines in respect to thermostability. Japanese preparation showed higher stability in all temperatures tested as compared to above mentioned vaccines. It was shown that when based on presented figures, and using interpolation method, it is possible with a high degree of probability foresee a decrease of vaccine titer at optional temperature.

WHO oversees the quality control of BCG vaccine via a system that includes regular testing of products by in vitro methods and clinical trials. Three parent strains of BCG (Glaxo-1077, Tokyo-172, and Pasteur-1173P2) account for over 90% of the vaccines currently in use worldwide. Important characteristics of the vaccine preparations are summarized here, along with their physical-chemical properties. In instances where diagnostic criteria for tuberculosis are stringent, there is no evidence that when administered to newborns different preparations of BCG vaccine exhibit different efficacies; however, the incidence of BCG-associated adverse reactions does correlate with the type of preparation. Other factors, including dose, administration technique, and recipient characteristics are also important in determining vaccine-associated reactions.

Control methods for this type of vaccines include tests on identity, absence of contaminating microorganisms and safety which are required for any vaccine. In addition, for the control of vaccines for immunostimulation in cancer therapy some special methods for safety and potency testing are required. Some assays are proposed, such as stimulation of lymphocytes in vivo and in vitro, stimulation of macrophages (listeria clearance) in mice and the prophylactic and therapeutic tumor model in mice. Details of these tests are given in the companion papers II and III. The influence of the method of preparation of BCG vaccines on its mode of action in some of these models will be emphasized.

Four consecutively produced batches of Bacillus Calmette-Guérin (BCG) especially intended to be used for cancer immunotherapy were investigated for consistency of the vaccine. Each batch was investigated directly after production of the vaccine, so that the four batches were not tested simultaneously. The activity of the four batches was investigated in general safety assays, immunostimulation assays, and two different tumor models. General safety assays showed dose-dependent growth retardation and increased serum glutamic pyruvic transaminase activity in mice, and a long-lasting temperature rise in rabbits after IV administration of the BCG preparations. In a skin reactivity assay, reactions were found acceptable for all preparations when compared with a reference batch. The results of the immunostimulation and antitumor studies can be summarized as follows. All four batches induced a specific delayed-type hypersensitivity reaction to PPD, indicating the induction of cell-mediated immunity. A stimulating effect on lymphoreticular organs was concluded from increased spleen weight and enhanced cell proliferation in draining lymph nodes. Enhanced macrophage function (phagocytosis and killing of bacteria) was demonstrated by an increased resistance to Listeria monocytogenes. YAC lymphoma target cells were killed nonspecifically by BCG-activated peritoneal exudate cells (PEC), indicating the induction of natural killing activity by BCG. Intralesional injection of BCG induced tumor regression in the guinea pig line 10 hepatocellular carcinoma, followed by immunity to the line 10 tumor. In the murine 5D04 squamous cell carcinoma, BCG had no effect on the primary tumor. However, IV-injected BCG resulted in a decreased number of lung metastases. In general, the four consecutively produced batches showed similar safety and activity in the immunostimulation assays and antitumor activity. Since only minor differences between the batches were found, which can also be attributed to the variation in experimental conditions common to biological assays, it is concluded that the vaccine batches produced show an acceptable consistency.

The level of antituberculous immunity seems to be related to the number of memory T cells induced. This may vary as a function of the multiplication and persistence of BCG in host tissues. The most important requirements for a BCG vaccine are, therefore, the immunogenicity of the strain, the high proportion of live to dead bacilli, and adequate dispersion and low levels of soluble antigens. The surface-grown Pasteur BCG vaccine contains a very high proportion of bacilli killed by ball-milling and freeze-drying. It also contains clumps and soluble antigens, all factors influencing cell-mediated immune processes and viability control. Therefore, several batches of vaccine were prepared on an industrial scale using one of the most immunogenic strains (French 1173 P2) and grown as dispersed bacilli by a modified cell type culture method. This method provided fully viable, well-dispersed vaccines which have a viability and heat stability superior to that of the classical surface-grown BCG. The immunogenicity was checked by multiplication and persistence in mouse organs and the skin reactivity and tuberculin hypersensitivity in guinea-pigs showed results comparable to those obtained with classical vaccine. Small-scale tests in children showed superior immunogenicity of the dispersed as opposed to the classical vaccine and there was no suppurative adenitis.

Batches of freeze-dried BCG vaccine were produced by using two different substrains--Moscow (SL 374a) and Paris (SL 1173 P2). The biological activity of the vaccines was studied by the following tests: In the laboratory--viability, heat stability, homogeneity, skin reactivity, allergenic potency and immunogenicity in guinea pigs. In the field--local lesions and postvaccination tuberculin sensitivity. All the batches were produced by using the same technique and production methods. The Paris substrain vaccines showed less viability, but higher heat stability and skin reactivity. It is to be noted that when the VKL medium was used (instead of Sauton) the Paris substrain vaccines showed much lower immunogenicity in guinea pigs and, at the same time, much higher skin reactivity. In the field studies the Moscow substrain vaccines showed higher local lesions and tuberculin sensitivity. In other experiments vaccines produced from the same substrain (Moscow) but in different production centers were compared. It was found that the vaccines differed (according to the production methods used) in terms of some laboratory tests (viability, heat stability, homogeneity) but these differences were not associated with significant differences when studied in the field.

The stability of the viability of the Hungarian BCG Reference Preparations (Vaccine Bch. Nos: 265, 456, 505) was tested according to the recommendation of the World Health Organization. The BCG viable units of the vaccines were estimated from the colony counts determined on solid medium. The control data of the BCG viable units expressing the stability in 10(6)/ml values were analysed up to 7 years in a three-step statistical model applying unbiased parameter estimates, valid hypothesis test and multiple comparison. The presented model verifying the stability of the reference preparations ensures the reliability of the assays to accept or reject the viability at controlling routine BCG vaccines in comparison with the reference preparations.

Some parameters affecting the standardization of a tuberculin preparation have been evaluated and it has been shown that: 1) The loss of tuberculoprotein on the surfaces of containers is in the order of 0.15 mug/cm2 and the 0.18 mug/cm-2 for glass and plastic surfaces respectively, and that this loss can be prevented by the addition of a nonionic anti-adsorption agent such as Tween 80. 2) For non-stabilized tuberculin PPD solutions the losses of PPD due to adsorption increased linearly with the Surface to Volume ration. 3) Exposure to light had a deleterious effect on tuberculin PPD decreasing its biological potency and altering its appearance. This effect increased with the dilution of the tuberculoprotein solution, and can be prevented by storing the tuberculin in amber containers. 4) The potency of tuberculoprotein was dependent on its molecular weight, and the % distribution of tuberculoprotein molecules of different molecular weight varied from batch to batch. This variation can be eliminated by preparing a large batch of tuberculin in a dried form sufficient to fill the demand for many years to come. 5) The route of injection and the species or strains of mycobacteria used for sensitization of guinea pigs affected the relative potency of a tuberculin preparation. 6) The size of a tuberculin skin reaction increased as the volume of tuberculin injected intracutaneously into sensitized guinea pigs was increased although the number of tuberculin units administered was the same. 7) The sizes of skin reactions to certain doses of tuberculin was affected by other doses of tuberculin being injected simultaneously at other sites. 8) Sex and age of guinea pigs affected the size of the tuberculin skin reaction. 9) The genetic make-up of the test animals affected the relative potency of a given tuberculin preparation. 10) Racial differences among various populations might account for different levels of tuberculin reactivity to a given tuberculin preparation. It is hoped that this work has made us aware of the many problems which can be encountered in standardizing tuberculin and it is also to be hoped that the solutions we have offered to some of these problems can be useful to those attempting to standardize allergens other than tuberculin.

In protection tests on white mice vaccinated with BCG vaccine and challenged with a pathogenic strain of Mycobacterium bovis, the survival times are considerably altered by several variables. In the strains of mice used mainly in this study (NMRI and Albany), the median survival time of a group was roughly doubled in the sensitive range of the test system either by a twofold increase in the immunization period, a threefold decrease in the challenge dose or a 100-fold or less increase in the vaccine dose. The shape of the survival curve of an animal group depends on the median survival time achieved. The Gaussian distributions (sum curves) of the logarithms of the individual survival times are near linearity and parallelity in groups of animals which either survive for short or very long periods. In an intermediate range, however, the survival curves show a flatter and sometimes S-shaped course. This intermediate range of survival corresponds to the time at which the lung findings shift from acute to chronic. The occurrence of acute or chronic findings depends on the individual survival time after challenge. The autopsies show that both findings are equally frequent approximately equal to 35 days after challenge. Individual survival times should be evaluated by non-parametric methods due to their non-normal (bimodal) distribution. Evaluation of the gross lung findings supports these results but is, however, less efficient. The discriminating power of the test system can be altered by changes in any of the variables and is best when animal groups attaining less than 20 days median survival time are compared with groups attaining greater than 30 days. A twofold increase in the median survival time generally provides evidence of significance that may already be obtained 30 days after challenge. With a vaccination-challenge interval of 21 days or more, a 50 microliter vaccine dose generally induces a significant increase in the survival times of the vaccinated animals versus non-vaccinated controls. With increasing immunization periods (vaccination-challenge interval), however, a difference in the efficacy of several vaccines or vaccine doses will be evened out.

We treated 40 patients with superficial bladder cancer via intravesical bacillus Calmette-Guerin for 1) prophylaxis against tumor recurrence, 2) residual carcinoma or 3) flat carcinoma in situ. A single course of intravesical bacillus Calmette-Guerin therapy was successful in 6 of 11 patients (55 per cent) treated for residual carcinoma and 6 of 12 (50 per cent) treated for carcinoma in situ. Of 17 patients receiving a single course of bacillus Calmette-Guerin for prophylaxis 11 remained free of tumor during short-term followup. A second course of therapy was administered to failures in each treatment category, which resulted in favorable responses in 5 of 6 patients treated for prophylaxis, 2 of 5 treated for residual tumor and 3 of 6 treated for carcinoma in situ. Over-all complete responses were achieved in 16 of 17 patients (94 per cent) treated for prophylaxis, 8 of 11 (73 per cent) for residual carcinoma and 8 of 12 (66 per cent) for carcinoma in situ, with a mean followup from the final treatment of 9.3, 12.3 and 7.9 months, respectively. Favorable results occurred more frequently among patients who exhibited a granulomatous inflammatory response in the bladder and delayed hypersensitivity skin test response to purified protein derivative. Marked variability in viability of bacillus Calmette-Guerin organisms was observed among different lots of bacillus Calmette-Guerin, and a direct relationship was observed between bacillus Calmette-Guerin vaccine viability and therapeutic efficacy. Most patients who failed initial therapy with a low viability lot of bacillus Calmette-Guerin responded favorably to re-treatment with a higher viability lot. The results suggest that the level of viability of each lot of bacillus Calmette-Guerin vaccine should be verified before clinical use.

Potency differences between bovine purified protein derivative tuberculin preparations produced in two different centres and also between preparations produced within these centres, were detected in tuberculous cattle and correlated with potency differences in guinea-pigs. Although assays in groups of guinea-pigs sensitized with either killed Mycobacterium bovis or live BCG identified the weak batches and listed the tuberculins in the same order of potency as the cattle assays, there were nevertheless significant differences between potency estimates according to the mode of sensitization and the preparations compared. The implications for the standardization of tuberculin preparation in general are discussed.

In Hungary the control of immunobiological preparations has been regulated by legal orders since 1938. In the meantime the pertinent rules have been modifed several times, to keep them abreast with current development. The authority of state control has been vested into the Vaccine Control Department of the National Institute of Public Health (OKI), which in this capacity has maintained an intensive collaboration with the producer of immunobiological preparations, the HUMAN Institute of Serobacteriological Production and Research (HUMAN). As a result, several important vaccine preparations (pox, DPT, DT, tetanus, typhoid and BCG vaccines) employed in compulsory immunization programmes have been improved considerably in respect of safety and efficiency, on the basis of laboratory tests, controlled field trials and epidemiological observations, described in detail in this review.

An in vitro test for measuring the reaction of the draining lymph node after BCG vaccination and an in vitro test based on the stimulation of lymphocytes by concanavalin A were used to demonstrate immunostimulating properties of different BCG vaccines. A marked difference was seen between vaccines grown as a surface pellicle and ground in a ball mill, and those which were prepared from dispersed homogeneous cultures. In both systems the ball mill preparations were the less active.

Connaught freeze-dried BCG vaccine is distributed in amber vials sealed with grey butyl rubber stoppers. This report gives data showing the stability of BCG vaccine in this presentation at 4 degrees C and 37 degrees C, for 1, 10, 20 and 50 dose vials. The results demonstrate that BCG vaccine prepared in vials is a stable product and could be useful in mass-immunization campaigns.

In previously published studies, a number of BCG strains used in several production laboratories were compared in animal models. Liquid vaccines from the different strains were prepared in one laboratory with a uniform technique, the aim being to obtain uniform in vitro properties. In the studies reported here, such vaccines were compared by means of vaccinating children in India and Denmark and then measuring their post-vaccination skin lesions and tuberculin sensitivity. One strain induced delayed hypersensitivity strikingly weaker than that induced by any of the others, although the vaccine was in no way inferior in terms of exhaustive in vitro tests. Differences among the other strains were slight, although sometimes statistically significant. The implications of such differences are discussed.

Although the field trials carried out by the Medical Research Council of Great Britain demonstrated that BCG vaccination can confer a substantial degree of immunity against tuberculous infection, it does not follow that BCG substrains other than the one used for those trials will produce equally favourable results. In fact, there is increasing evidence that different BCG strains may differ widely in their protective potency. The experiments described here further confirm these differences. They also show how the determination of the minimum dose of a BCG vaccine capable of delaying the development of tuberculous infection in mice and in guinea-pigs can yield reproducible data that may help to characterize individual BCG strains.The main purpose of these experiments was to determine the protective potency of Connaught freeze-dried BCG vaccine, lot 140, and to compare it with that of three other BCG vaccines. Marked differences were found with respect to the minimum protective dose for mice or guinea-pigs and the degree of immunity and tuberculin allergy produced in guinea-pigs as shown by the dose-response relationships recorded over a wide dosage range. The results suggest that the Connaught vaccine equals or surpasses the other vaccines in effectiveness.Such tests require a reference BCG vaccine of high protective potency for both animals and man.

Changes in the Danish BCG strain under certain regimens of subculture have been shown in preceding studies to be associated with selection of a minority population. Three Czechoslovakian BCG strains, all originally derived from the Danish strain but thereafter and in distinction from it maintained on potato media, have now been investigated. Changes in the immunizing potency of two of these strains have been attributed by other workers to employment of the richer potato media in place of Sauton medium as used for maintenance of the parent Danish strain. However, results from the present study suggest rather that selection of a pre-existing minority genotype or of a new mutant occurred. This proposal is supported by the finding that the third strain has maintained characteristics similar to those of the Danish parent despite many previous transfers on potato media.Another BCG strain investigated was the Japanese which, like the three Czechoslovakian strains, had been previously maintained on potato media. This strain has been shown in the present study to resemble the Danish strain in supporting a minority population yielding non-spreading colonies. Czechoslovakian vaccine prepared with seed culture supplied from Tokyo has retained characteristics similar to those of the Japanese parent. Although a majority population yielding spreading colonies appears so far to have been retained in both centres, it is considered that selection of the minority could still occur in the course of routine transfer.