Belarus has done literally nothing to respond to the coronavirus.  according to the Ferguson model they should have had 70,000 deaths by now. they've had 160.

https://www.usnews.com/news/world/articles/2020-05-09/belarus-holds-victory-day-parade-disregarding-coronavirus

CDC estimates mortality rate is . 4% close to some flus

 the statement that the research study did find a best case of the 15 million dead is correct. 

https://anu.prezly.com/coronavirus-is-highly-uncertain-and-the-costs-could-be-high?utm_source=email&utm_medium=campaign&utm_id=campaign_Ejmb_lbzJ.contact_RBhn_lDAN&asset_type=attachment&asset_id=171409#attachment-171409ttachment-171409v

Scroll to the bottom for link to the PDF of the research study.

 however the claim in the title " coronavirus will kill 15 million people” is far too strongly worded to be provable.  no pandemic has killed that many people in a century,  so the Bayesian prior is pretty low.  so far about 3300 people have died worldwide.

 some estimates of the actual fatality rate are much lower than those used here. South Korea,  which seems to have the best statistics,  is claiming about . 6%. cases in China have drastically slowed their growth already.  their   quarantine methods were far more effective than many experts had predicted,  showing both hope going forward and that experts aren't to be trusted. 

 the virus may mutate to be worse,  but on the other hand it may mutate to be better. doesn't do the virus any good to kill the host.

 the people dying seem mostly to be old and infirm.  the study doesn't consider that the unfortunate death of these people isn't necessarily bad for the economy in purely numerical terms.  the economy roared back from the Spanish flu and launched the roaring 20s.

 I think we need a diagram with a more supportable,  but still interesting hypothesis. 

New modeling from The Australian National University (ANU) looks at seven scenarios of how the current outbreak may impact the world's wealth, ranging from low-severity to high-severity.

In the low-severity model - or best-case scenario - ANU researchers estimate a global GDP loss of $2.4 trillion, with an estimated death toll of 15 million.

This virus was unknown before 2019, with no current known treatment or vaccine.  Results fighting it have varied wildly by country, from China's purported ~5% death rate to Italy's ~17% rate.  Infection rates seem to vary.  Full quarantine (China) contained it fairly well, while limited "lockdown" (Italy) did not. 

Origin has been assumed to be China, but the numbers just don't add up right for that.  Recent reports of severe pneumonia with flu-like symptoms near Turin, Italy in October thru December bear further investigation. 

WHO and CDC have said it spreads by aerosolization only, yet it survives and can be picked up for over 2 days on stainless steel. 

Tracking real origin may help in understanding how it spreads.  This may help to develop treatments, preventive measures, or vaccines.

If it didnt have a high rate of risk and danger, then it would have been treated just like a flu virus.

As has been seen that most of the cases are asymptomatic and the virus spreads through air, it is extremely difficult to control it. This difficulty is also compounded by the fact that the virus can lie dormant for many days or even weeks before deciding to activate itself in a person. So by the time a person shows symptoms he would have already passed it on to several people.  This particular strain of virus has been around for quite some time and does not seem to die or get eradicated: SARS, MERS, Swine Flu and now COVID. 

https://timesofindia.indiatimes.com/city/hyderabad/doctors-in-telangana-baffled-as-villagers-with-no-contacts-or-travel-test-positive/articleshow/75262536.cms

If nations are late in responding like Italy, Spain or blatantly ignore like the US, then fatality will be high. But if nations enforce strict lockdown, implement social distancing norms, and aggressive testing policies like South Korea, Japan, then fatality will be minimal. In fact, COVID-19 is known to be highly contagious but with a low mortality rate of 2-3% with the majority of infected individuals being asymptomatic.