Efficacy of BCG Vaccination in Prevention of Cancer: An Update: Brief Communication 2

Abstract

From 1949 to 1951, a controlled trial of BCG vaccinations was conducted in Puerto Rico. The 191,827 children, 1-18 years of age, initially enrolled in the study were skin-tested with tuberculin to determine their eligibility for vaccination. A total of 82,269 children were classified as reactors and not vaccinated. Of the 109, 558 nonreactors, 31,586 refused vaccination, 50,634 were vaccinated with BCG, and 27,338 were left unvaccinated as controls. We ascertained the incidence of cancer over an average follow-up period of 23.3 years in the latter two groups using the Puerto Rico Central Cancer Registry. By the end of December 1973, a total of 77 cancers had been diagnosed among the controls and 150 among the vaccinees. The overall incidence of cancer among the two groups was similar. Although a number of differences existed between the vaccinee group and the controls in regard to the incidence of cancer at various "sites", none of these differences was statistically significant. However, when cases of lymphosarcoma and Hodgkin's disease were combined for analysis, a statistically significant excess of cases occurred among the vaccinees. We concluded that BCG vaccination had no protective effect on the subsequent development of cancer in this population. The slight excess of cases of lymphosarcoma and Hodgkin's disease among the vaccinees raised the possibility that BCG may have had an adverse effect.

Early vaccination protects against childhood leukemia: A systematic review and meta-analysis

“…The manual search of references also provided additional six reports. Among studies which were excluded from the manual search, there were two studies that did not provide a non-leukemic group 40 , 41 , two studies enrolled patients at more than 20 of age 42 , 43 , one study had overlapping participants 44 and one study was a conference paper 45 . Hence, the total number of articles for final analysis was 14.…”

Potential health effects from non‐specific stimulation of the immune function in early age: The example of BCG vaccination

“…These results were reproduced in a few countries (106). In two large clinical trials, BCG vaccination was associated with increased incidence of lymphosarcoma and Hodgkin’s disease (107), and with stomach, kidney, and lymphopoïetic cancers (lymphosarcoma, lymphoma, Hodgkin’s disease and leukaemia) (108). Several authors have underlined the fact that in studies suggesting a protective effect, the BCG vaccine was administered neonatally (107–110).…”

“…In two large clinical trials, BCG vaccination was associated with increased incidence of lymphosarcoma and Hodgkin’s disease (107), and with stomach, kidney, and lymphopoïetic cancers (lymphosarcoma, lymphoma, Hodgkin’s disease and leukaemia) (108). Several authors have underlined the fact that in studies suggesting a protective effect, the BCG vaccine was administered neonatally (107–110). More recently, results from a European multi‐centre population‐based case–control study suggested that BCG vaccination was associated with a decreased incidence of melanoma (111), and with better melanoma survival (112).…”

Association between Bacillus Calmette–Guérin vaccination and lymphoma: a population‐based birth cohort study

“…The majority of these studies did not find a significant association between BCG vaccination and the risk of lymphoma . Villumsen et al suggested that higher transmission rates of Mycobacterium tuberculosis in the general population may explain the lack of effect of BCG vaccination observed in older studies .…”

“…Epidemiologic studies of the relationship between BCG vaccination and lymphoma are rare and have led to conflicting results from protective to harmful , and null effects . Moreover, these studies suffer from serious methodological limitations such as the use of self‐report for determining BCG vaccination status.…”