Outcome of strict implementation of infection prevention control measures during an outbreak of Middle East respiratory syndrome.

BACKGROUND: The objective of this retrospective cohort study was to assess the impact of implementation of different levels of infection prevention and control (IPC) measures during an outbreak of Middle East respiratory syndrome (MERS) in a large tertiary hospital in Saudi Arabia. The setting was an emergency room (ER) in a large tertiary hospital and included primary and secondary MERS patients.

METHODS: Rapid response teams conducted repeated assessments of IPC and monitored implementation of corrective measures using a detailed structured checklist. We ascertained the epidemiologic link between patients and calculated the secondary attack rate per 10,000 patients visiting the ER (SAR/10,000) in 3 phases of the outbreak.

RESULTS: In phase I, 6 primary cases gave rise to 48 secondary cases over 4 generations, including a case that resulted in 9 cases in the first generation of secondary cases and 21 cases over a chain of 4 generations. During the second and third phases, the number of secondary cases sharply dropped to 18 cases and 1 case, respectively, from a comparable number of primary cases. The SAR/10,000 dropped from 75 (95% confidence interval [CI], 55-99) in phase I to 29 (95% CI, 17-46) and 3 (95% CI, 0-17) in phases II and III, respectively.

CONCLUSIONS: The study demonstrated salient evidence that proper institution of IPC measures during management of an outbreak of MERS could remarkably change the course of the outbreak.