Epidemic trends, public health response and health system capacity: the Chilean experience in four months of the COVID-19 pandemic.

Objectives. To report the surveillance of COVID-19 pandemic in Chile and analyse the response to public health interventions implemented from 3 March to 30 June 2020 and to assess the risks of collapse of the health care system. Methods. We analysed the effective reproductive number, underreporting of cases, burden of critical beds, case fatality ratio and number of diagnostic RT-PCR for SARS-CoV-2. Results. After an accelerated onset, the COVID-19 pandemic seemed to be relatively controlled in Chile (late April 2020), with reproductive numbers close to 1.00. However, at this time, the load of infected patients was high, with an important number of underreported cases; the diagnostic effort was still limited and heterogeneous across regions. After 1 May up to 30 June a marked exponential increase in the number of cases was observed with a peak on June 14. In this last period the occupation of intensive care unit beds increased to saturation level (89% nationally; 95% in the Metropolitan Region). Conclusions. Our findings suggest that the implemented public health interventions have been initially effective in decreasing the spread of the pandemic. Premature decisions to relax these interventions may have resulted in a rebound in cases with a rapid saturation of the health care system.