@AnalyticalEngine - I'm not holding out too much hope on vaccines because of SARS and MERS, but there are phase 3 clinical trials happening right now on a number of antivirals and antibody treatments. Initial data on remdesivir should be coming out in April
so fingers crossed there.
My biggest fear is around the potential for ADE in a second wave of infection, but that's entirely speculative and not grounded in evidence. Apparently the in-vitro studies I referenced in earlier posts showing SARS ADE are pretty controversial in immunology Twitter-verse.
Back-of-the-envelope-ing IFR numbers
I think the WHO is right that the "iceburg" of underreported cases in China data is shallower than we'd like to believe (link
The numbers for Diamond Princess right now on this tracker
are 696 cases, 6 dead, 242 recovered, and 34 active critical. They tested all passengers on ship, and I haven't heard of any released passengers falling ill unexpectedly, so I am going to assume CFR ~= IFR.
Assuming no active cases die you have 6/696 = 0.9% IFR.
But obviously age distribution of patients is skewed, with median passenger age in the 60-69 bucket.
Assuming CFR for 60-69 bucket is around 3x total, we're looking at an age-corrected 0.3% cIFR as our floor.
More likely, some of the still-active severe cases will also die. If we assume long-lived cases to be neither more nor less likely to tend toward death and just compare deaths to recovered ratio we have 6/(242+6) = 2.4% IFR and 0.8% cIFR as a reasonable estimate if advanced medical care is available.
This is around where South Korean numbers are right now with nCFR = 0.7% for early stage deaths. Note that they've tested around 178k for 6.8k known cases, so I'm inclined to believe the "iceburg" is not that deep, no more than 2x to represent those who are asymptomatic and have PCR test failures.
If we assume in locales with overloaded hospital systems that all historically critical cases will end in premature death, our ceiling cIFR becomes a whopping 5.4%. This mirrors critical case rate from China's CDC
tl;dr: As someone with no knowledge, training, or experience in epidemiology, I'm estimating IFR for covid-19 will fluctuate between 0.5% (best case, intensive care for all those who need it) and 5% (no medical care available, hospitals swamped). This includes underreported asymptomatic cases and assumes age distribution of the infected roughly imitates China's in early months of the outbreak.
Looks like some more legit Diamond Princess statistical analyses
are still in flight.
Why don't people care?
Some friends: Ugh, this is so overblown, you're way more likely to die of the flu. People are just worried about this because it comes from China and they're racist.
Me: Hey, you visit a lot of people's houses for your work. You may want to consider wearing a mask so you become less of a vector for this spreading.
Husband: I work for the government. If I need to do something, I'm sure they'd tell me.
Me: You are going to be on a plane with your seventy year old mother to visit your centenarian grandmother. Maybe drop them off a couple masks?
Husband: No, thanks.
Me: Have you gotten your flu shot this year?
Mother (sixty-year-old): I don't get vaccines. I'm healthy.
Me: Okay, but this coronavirus thing is going around and it'd be good if you were protected against other respiratory diseases like flu or bacterial pneumonia in case you needed to be hospitalized. Don't want a secondary infection.
Mother: I mean, I probably won't get the vaccine. Sorry. Also, can I borrow some money from you? I'm thinking now is a good time for me to start a business in order to save for my retirement.
Panic is bad, but willful complacency which contributes to emergency/panic state feels worse? I don't know, I feel like a Cassandra.