This is a useful BCG systematic review concerning childhood protection against TB- worth reading in detail.

Longterm BCG protection into adulthood – vaccine efficacy (VE) 10-19 years post BCG was 58% (95% CI 27 to 76) p=0·002 and there was still a non-significant signal occurring in the 30-39 year group (VE 42%) in this large observational study from Norway.

BCG halves neonatal mortality – also read this important commentary from Dr Frank Shann in 2012. There are also heterologous protective effects of measles vaccination in infants.

A team is running a current RCT of neonatal BCG in Melbourne to examine immune correlates  and influence on infection and allergy. Existing evidence of BCG influence on childhood allergy was summarised here by Freyne and Curtis – conflicting relatively weak evidence; hence one of the rationales for the trial . Other related papers of interest include:

• Curtis, N et al. Comparable CD4 and CD8 T cell responses and cytokine release after at-birth and delayed BCG immunisation in infants born in Australia. Vaccine. 2016 Jul 29;34(35):4132-9.
• Curtis, N Et al.  BCG-associated heterologous immunity, a historical perspective: experimental models and immunological mechanisms. Trans R Soc Trop Med Hyg. 2015 Jan;109(1):46-51.