Non-specific effects of vaccines The idea of vaccines having non-specific effects was first proposed in 1991 from a study in Senegal, West Africa. It was discovered that children receiving high-titre measles vaccine (HT) at 6 months of age had higher mortality than children who received the standard titre measles vaccine (STD) at 9 months of age. The difference was found only for girls. A study from Haiti confirmed the effect. Since children vaccinated with HT had lower mortality than their equivalents who had not received any measles vaccine, the difference in mortality between recipients of HT vaccine and STD vaccine was explained by a non-specific beneficial effect of the STD measles vaccine rather than a harmful effect of the HT vaccine. The non-specific beneficial effect of STD measles vaccine on child mortality has been reconfirmed in many data-sets.