COVID-19 outbreak in Iran may be much larger than we think

Iran may have significantly more cases of Coronavirus Disease 2019 (COVID-19) than the 43 that were reported to the public. A brief report published in Annals of Internal Medicine suggests that Iran would need to have approximately 18,300 cases of COVID-19 to export just three cases to countries with low travel volume from the region.

Twenty-eight countries have confirmed cases of COVID-19 since the epidemic began in late 2019. Between February 19-23, 2020, Iran reported its first 43 cases with eight deaths and three cases originating from Iran were identified in other countries. According to experts, this is concerning because a large epidemic in Iran could further fuel global dissemination of COVID-19.

University of Toronto researchers used data from the International Air Transport Association (IATA) to quantify a more accurate COVID-19 outbreak size in Iran and anticipate where infections originating in the country may spread next. They assessed flights between Iran and other countries using direct and total traveler volumes and final destination cities of travelers originating in Iran last February. As of February 23, COVID-19 cases that originated in Iran had spread to Canada, Lebanon, and the United Arab Emirates. Given the low volume of air travel between Iran and these countries, the researchers estimated that 18,300 COVID-19 cases would have had to occur in Iran, assuming an outbreak duration of 1.5 months in the country.

The authors note that the lack of identified COVID-19 cases in countries with far closer travel ties to Iran, such as Iraq, Syria, and Azerbaijan, suggests that cases in these countries are being missed, rather than being truly absent. They warn that public health initiatives in this region are urgently needed.