Question to the Department of Health and Social Care:
To ask the Secretary of State for Health and Social Care, what the current reproduction number or R-rate is of (a) chlamydia, (b) gonorrhoea and (c) syphilis.
The current reproduction number or ‘R’ of chlamydia, gonorrhoea and syphilis is not known, as R number estimates for sexually transmitted infections (STIs) require behavioural information which cannot be easily measured.
The calculation of R for a typical STI differs from many other infections, in that it does not depend only on the population density of susceptible people, but rather the transmission probability per sexual partner and the number of sexual partners during a period of time, as well as the time spent in the infectious state. The value of R differs between different sexual networks and groups at higher risk of STIs as well as over time and cannot be generalised to the overall population.