The Available Evidence Does Not Support the Claim of Nitikin et al That 4CMenB Is a Cost-effective Way to Reduce Gonorrhea Incidence

In their mathematical modelling study, Nikitin et al., evaluated the cost-effectiveness of vaccinating men who have sex with men (MSM) with 4CMenB to protect against gonorrhoea [1].They concluded that "4CMenB vaccination of MSM gains QUALYs and is cost saving at any uptake level."I would suggest this conclusion is premature.The efficacy of the intervention is based on their assumption that one/two doses of 4CMenB will reduce the incidence of gonorrhoea by 26%/40%.These estimates are taken from a retrospective observational study [2].It is unclear why the authors chose to use these efficacy estimates rather than those from the only published randomized controlled trial (RCT) of this intervention?In the DOXYVAC RCT in MSM in France, the authors found that the receipt of two doses of 4CMenB was not protective against incident Neisseria gonorrhoeae infection (adjusted Hazard ratio 0.78, 95% CI 0.6-1.01)[3].Observational studies are susceptible to a number of biases which can be reduced or eliminated by studies using randomization [4].If we used the more reliable efficacy estimates from the DOXYVAC study, then we should conclude that the 4CMenB vaccine either has no effect or, at best, a very small impact on the acquisition of N. gonorrhoeae.The results of RCTs with novel vaccines specifically targeting N. gonorrhoeae (rather than N. meningitidis) are eagerly awaited