COVID-19 reaches 147 areas worldwide; new cases in China declining

As of March 17, 147 countries, areas, or territories reported confirmed cases of COVID-19, according to catastrophe risk modelling firm AIR Worldwide. The country most affected by the outbreak has been China, which has reported 82,007 cases and 3,338 deaths; however, China has also reported that the number of new cases there has continued to decline due to early and aggressive containment measures.

Outside China, a total of 102,968 cases of COVID-19 have been reported, with 4,191 deaths. South Korea has reported 8,320 cases and 81 deaths; new cases there have also been reported to be declining. The largest outbreak is currently in Italy with 27,980 cases and 2,158 deaths, followed by Iran with 16,169 cases and 988 deaths, and Spain with 11,178 cases and 491 deaths. Case numbers are growing in the United States as testing is expanding, with 3,536 confirmed cases and 58 deaths from the disease.

“Based on the estimations and projections from the AIR Pandemic Model, we estimate that this may represent a moderately conservative projection of cases; the vast majority will be asymptomatic or have mild symptoms,” said Dr Narges Dorratoltaj, senior scientist at AIR Worldwide. “AIR projections also suggest that the number of mild to moderately symptomatic cases globally from March 18 to April 1 could range between 600,000 and 2,000,000, and the number of severe cases could range between 200,000 and 900,000, with deaths ranging from 10,000 to 30,500.”

AIR’s model-based estimates account for uncertainty and underreporting. Mild to moderate symptoms are the types of cases least likely to be captured in the official numbers, but even for severe cases and deaths, it is likely that there will be significant underreporting.

Dorratoltaj noted: “The difference between the low and high ends of the range is driven by a few factors. Uncertainty in the reported number of confirmed cases and the transmissibility of the virus play a significant role. Specifically, the lower end of the range represents a scenario where the true number of cases is relatively closer to what has been reported than estimated, and the possibility that containment measures (such as social distancing and quarantine) become more successful in reducing the transmission. If such containment measures—driven by international and/or local authorities—are successful, this could restrict the human-to-human transmission sufficiently to bring the eventual number of cases to or even below the low end of the modelled projected range of cases.”