The non-specific effects of vaccines

Systematic Review of the Non-Specific Effects of Bacillus Calmette-Guérin Vaccine on Child Mortality

“…5 million deaths of children under 5 years in 2015, a very impacting number for the families well being and for the nations. In studies in the United States and the United Kingdom in the years 1940 to 1950, Bacillus Calmette-Guérin (BCG) vaccine was associated with a 25% reduction in all-cause child mortality from diseases other than tuberculosis [3]. Subsequently, observational studies in countries with high infant mortality rates supported these findings [4].…”

Non-specific and sex-differential effects of routine vaccines: What evidence is needed to take these effects into consideration in low-income countries?

“…[18][19][20] The beneficial effect of MV has been particularly good for girls. 3,4,16,20 However, these results have not had any consequences for the immunization program in terms of assessing the optimal age of measles immunization, the number or doses or the impact of measles immunization on child survival. On the assumption that RCT will be more convincing, we tested the effect of providing MV at 4.5 months of age in addition to the usual MV at nine months of age in a large randomized trial.…”

“…There is no evidence base for DTP vaccination having a beneficial effect on child survival in low-income countries. 4 It might have been logical to assume that it would have a beneficial effect but no study demonstrated that DTP is associated with better survival before the introduction of DTP. 36 There is now a lot of evidence suggesting that DTP may have negative effects on child survival.…”

“…2 The NSE may well be more important for overall child survival than the lives saved by specific disease prevention. [2][3][4] The WHO's Global Advisory Committee on Vaccine Safety (GACVS) has recently stated that it will keep a watch on the non-specific effects (NSE) of vaccination. GACVS indicated that "conclusive evidence for or against non-specific effects of vaccines on mortality, including a potential deleterious effect of DTP vaccination on children's survival as has been reported in some studies, was unlikely to be obtained from observational studies."…”

Assessing vaccine effectiveness of publicly funded vaccination programs in Queensland

“…It is important to identify and understand both specific and non-specific effects of vaccination so that vaccination schedules can both maximise benefits and minimise potentially detrimental effects of vaccines (321). Among the evidence of non-specific effects are findings from low income settings, indicating the co-administration of MMR with DTPw may be associated with higher mortality than administration of DTPw prior to MMR (325), and that females may be more susceptible to non-specific vaccine effects than males (326,327). While most of the studies of non-specific effects of vaccination have come from low-income settings, there is also some evidence from high-income countries.…”