Background and objectives: The basic reproductive rate of and STD is an important parameter from which the success of intervention strategies can be predicted.
Goal of the study: To evaluate different methods to estimate the basic reproductive rate.
Results: Two different methods of estimating the basic reproductive rates of Neisseria gonorrhoeae and Chlamydia trachomatis yielded discrepant results. One of the methods, which is based on the assumption of the absence of acquired immunity, yielded unrealistically low estimates of the basic reproductive rates.
Conclusion: In conjunction with other epidemiologic evidence, we infer that some form of acquired immunity to these pathogens must exist and discuss its implication for control.