Just two days ago, Bahrain reported their first imported case of COVID-19, in a Bahraini citizen returning from Iran. Yesterday morning, we learned via the Bahrain MOH: 9 More Imported COVID-19 Cases (ex Iran).
Over the past 24 hours, new cases have been detected, and about 2 hours ago the Bahraini MOH announced 3 more cases (apparently all linked to Iran), bringing their total to 26.It isn't just Bahrain. Over the past 48 hours Kuwait has announced roughly a dozen cases, also coming from Iran, and we've seen other cases detected in Canada, Lebanon, and Oman over the past 7 days.
Yesterday, MedRxiv published a non-peer-reviewed paper which attempted - based on the recent exportation of just 3 cases from Iran - to calculate the number of likely COVID-19 cases inside Iran.
This is a method we've seen used previously with MERS-CoV in Saudi Arabia (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016), and while it infers a lot from a small amount of data, it can be a valuable tool for roughly estimating likely cases.
Yesterday's study, based on just 3 exported cases, estimated there must have been 18,300 (95% confidence interval: 3770 to 53,470) already in Iran. While I'm not qualified to comment on the math, their methods, or their conclusions, it is worth noting that over the past 48 hours the number of exported cases from Iran has increased more than 12-fold.
Estimation of COVID-2019 burden and potential for international dissemination of infection from Iran
Ashleigh R. Tuite, Isaac Bogoch, Ryan Sherbo, Alexander Watts, David N. Fisman, Kamran Khan
We estimated that 18,300 (95% confidence interval: 3770 to 53,470) COVID-19 cases would have had to occur in Iran, assuming an outbreak duration of 1.5 months in the country, in order to observe these three internationally exported cases reported at the time of writing. Results were robust under varying assumptions about undiagnosed case numbers in Syria, Azerbaijan and Iraq.
Even if it were assumed that all cases were identified in all countries with certainty, the "best case" outbreak size was substantial (1820, 95% CI: 380-5320 cases), and far higher than reported case counts. Given the low volumes of air travel to countries with identified cases of COVID-19 with origin in Iran (such as Canada), it is likely that Iran is currently experiencing a COVID-19 epidemic of significant size for such exportations to be occurring.
This is concerning, both for public health in Iran itself, and because of the high likelihood for outward dissemination of the epidemic to neighbouring countries with lower capacity to respond to infectious diseases epidemics.
(Continue . . . )
As to how a major COVID-19 epidemic could have taken hold in Iran so quickly, there are reports - disputed by Iranian officials - that at least one Iranian airline continued to make regular flights to and from China over the past 3 weeks.
If the number of exported COVID-19 cases from Iran reported over the past couple of days is any indication, the Middle East may well become the next major hotspot for this undeclared pandemic.