This is the second study to attempt replication of Banas et al (2023) on inoculation messages. The original experiment demonstrated that inoculation messages could foster resistance to anti-vaccine conspiracy theories without significantly affecting motivational threat. However, using the same materials, Bessarabova and Banas (2024), we counted as the first replication, reported significant effects on both variables. To re-investigate the effect of these inoculation scripts, we conducted a conceptual replication experiment in the UK. In our replication, we measured and controlled conspiracy mentality as the potential variable that may influence MMR vaccine conspiracy beliefs. Our analyses showed significant effect of inoculation treatments in reducing the levels of MMR vaccine conspiracy attitudes without stimulating motivational threat. Yet, they did not generate significant effects on other conspiracy beliefs. Conspiracy mentality, included as covariates, also showed significant results in predicting MMR vaccine conspiracy attitudes and other content-specific conspiracy beliefs.