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Comment by dongping | Hacker News Reader

I'm not qualified to assess the risk, but if the there's indeed ADE (antibody dependent enhancement),[1][2] people once infected with a milder strain may suffer from more severe symptom from the deadlier strains, thus killing more people in the end.

I'm wondering how we may rule out this worst case scenario.

[1] Is COVID-19 receiving ADE from other coronaviruses? https://www.sciencedirect.com/science/article/pii/S128645792...

[2] New blood tests for antibodies could show true scale of coronavirus pandemic https://www.sciencemag.org/news/2020/03/new-blood-tests-anti...

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ADE is more a problem for the vaccine approaches. It is one reason we may never have a vaccine for this disease.

Hard to rule out worst case scenarios, we just have to work with what we have and make hard choices.

>ADE is more a problem for the vaccine approaches. It is one reason we may never have a vaccine for this disease.

This is at least partly why there are no SARS/MERS vaccines. There's a paper I'll try to dig up where 4-8 (can't remember) modified vaccine candidates were tested in multiple animal species, and in each case except one, immunity was conferred but exposure to the virus lead to a dangerous autoimmune response which destroyed lung tissue.

That's not ADE as I understand it. ADE is where the virus gets grabbed more easily by cells thanks to the antibodies on it proving handles.

Well yes, because of ADE the normal antibodies released by the immune response immediately increase the replication rate so you have a far more severe reaction upon infection than you would otherwise.

That's why I'm waiting for confirmation of immunity. So far I've only seen increasing numbers of reports of reinfection but that may just be faulty testing.

My understanding is that we had SARS vaccine candidates ready for human testing, but funding died off once SARS disappeared.

Maybe in this context, making a "hard choice" is accepting that something like 0.3% of the world population dies? Historically we saw worse and recovered, while trying to engineer something with no guarantee it won't be massively worse, using an unprecedented and more or less unstoppable strategy, might not be the most prudent thing to do. Looks like a good movie plot though.

We don't have that option, unfortunately. In real life we're dealing with hospitals permanently jammed and new covid patients keep dying every 6 months, plus the huge economic costs from keeping hospitals _at_ capacity as opposed to 10x over capacity.

If the total cost is under $6 trillion, I think the Fed can swing it.

What about Dengue?

Dengue is a different virus. All viruses behave differently.

Wow. What an answer. All flaviviruses cause ADE. Only few attenuated vaccines worked as a strategy. And no they don't shed.

Article [1] is dated Feb 12, and contains the sentence:

"Instead, it [SARS-CoV-2] appears to be no more concerning than the influenza virus." The citation for this claim is an article in Canada's National Post.

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