Tyranny of numbers

Update on Iran’s Covid-19 epidemic

Posted in COVID-19 by Djavad on May 17, 2020

In a recent webinar at Harvard’s Middle East Initiative and a virtual conversation with Princeton’s Iran Center (here) I discussed the extent of the Covid-19 epidemic in Iran, and each time noted that, given the country’s high level of economic distress and the government’s tight budget, stay-at-home rules may not last very long.  This has come to pass now. A few weeks ago the government relaxed the social distancing guidelines and, after a month of decline in the daily numbers of cases and deaths, both rates seem to be heading back up.

In this post, I bring up to date the graphs included in the above links and in my last post here.  I change the comparator country from Spain to Turkey because Turkey offers a more relevant comparison for Iran. It has roughly the same population and age structure, a similar Human Development Index, and is in the same income category as Iran – the upper-middle-income group according to the World Bank.  Turkey’s epidemic, which started two weeks after Iran’s, was more severe in terms of cases but less so in terms of fatalities.

The notable change in Iran’s situation from my previous post is the reversal of the decline in the numbers of cases, up by about 80 percent from two weeks ago.  The number of deaths follows the rise in the daily new cases, but the data on its possible reversal is less clear.

I also add a graph for the number of new tests, a factor that influences the speed of the spread of the infection following the resumption of work and travel.  In the absence of a vaccine, the only way to bring the reproduction rate of the virus to below one and keep the epidemic under control is to test a significant proportion of the population every few weeks (see Paul Romer’s fascinating posts on this subject here).  The significant shortfall in Iran’s testing compared to Turkey (0.2 per 1000 vs 0.5, or about 16000 vs 40000 per day) is probably due to the limits that sanctions have placed on Iran’s ability to purchase test kits.


Iran’s case is evidence for what happens when a country relaxes its stay-at-home rules, and adopts the Swedish model.  Sweden has avoided the type of lockdown we have seen in the rest of Europe at considerable cost to public health.  The data for Sweden shown below indicate much higher rates of infection and mortality than Iran (the higher variability in the rates is probably a reporting issue).  Importantly, Sweden does twice as much testing as Iran, which may help it keep its rates from increasing over time (Sweden does not report daily tests, only the cumulative total).  Moving closer to the Swedish model with inadequate testing may mean higher rates of infection and deaths in the coming weeks in Iran.



2 Responses

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  1. Karim (@Vakil_e_Roaya) said, on May 18, 2020 at 5:18 am

    Great article! Need to make changes to the legends of some of your graphs. For example, all your y-axis legends say the same thing, “Total tests per million” when you compare Iran and Sweden, two need to change.

    • Djavad said, on May 18, 2020 at 9:56 am

      Thank you for pointing out the mislabeling of the graphs for Sweden. Corrected.

      From: Tyranny of numbers
      Reply-To: “comment+2i1eh_sdrxw9cwjm6og4y7fnzo@comment.wordpress.com”
      Date: Monday, May 18, 2020 at 5:19 AM
      To: Djavad Salehi-Isfahani
      Subject: [Tyranny of numbers] Comment: “Update on Iran’s Covid-19 epidemic”

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