A vaccine isn’t coming
I don’t mean soon. I mean ever.
I keep reading about people who say that we just need to hold out until there is a vaccine. That it’s just a few months away, that a company in California invented a vaccine in 3 hours. None of that is going to work.
The way that cells normally fight a virus is to create unique ‘Y’ or ‘V’ shaped antibodies that stick to the surface of the virus and prevent it from attaching to a cell.
A virus without the antibodies will attach to the cell and push it’s genetic material inside. The cell is tricked into using that genetic material to make more viruses.
But inactivated viruses with antibodies attached to the surface can’t do that. They float around until they’re ‘eaten’ by a type of white blood cell called a macrophage.
And once you’ve had a virus, your body usually “remembers” which antibodies fight that virus.
So to make a vaccine, you’d usually either give the body a dose of the working antibodies, or you give it a weakened or killed version of the virus to ‘practice’ on so that it’s ready for the real thing.
And once you’ve survived a virus, (West Nile, Ebola, zika, etc.) you’re usually immune to that same virus for life.
There’s a virus called Dengue that’s transmitted by a mosquito bite. It’s really four viruses that are closely related.
The first time you’re infected, your body will fight it off, just like a normal virus. But after that, if you’re ever bitten by a mosquito with one of the other three types of Dengue, your immune system tries to respond with the same antibodies.
But those antibodies can’t totally cover the second virus up to inactivate it.
When the macrophage (white blood cell) tries to “eat” the virus, it gets infected and tricked into making more viruses.
This is called antibody-dependent enhancement, or ADE. There is currently no effective vaccine for Dengue virus because of it.
If you’re thinking “it infects white blood cells? Isn’t that what HIV does?” The answer is yes, and that’s a big part of why we can’t develop an HIV vaccine as well.
So why do we think this Coronavirus causes ADE?
For starters, it is closely related to two other Coronaviruses, SARS and MERS. Neither of those have vaccines, and both have been shown in laboratory animals to use ADE to infect white blood cells.
You don’t even need a second type of the virus. ADE is happening with the same virus that was cured the first time. You just need to get reinfected. And ADE makes the virus way worse the second time around.
The second reason is what we’ve seen from reports out of China.
People are getting reinfected, or maybe the virus is going dormant in their bodies and resurfacing.
It’s too early to know which, for sure, but the cases can be severe the second time around.
Also, the Chinese hospitals are using the serum (blood minus the cells) of people who’ve gotten the virus and recovered as medicine for infected people. This should be full of working antibodies that will help their bodies fight off the virus.
Sometimes the patient survives and sometimes they don’t. It should work every time, unless there’s antibody-dependent enhancement at work.
So no vaccine is coming. Once you’ve gotten this Coronavirus, it looks like you can get it again.
Unless we have a huge leap forward in medical science this year, any vaccine will be ineffective at best, and make you MORE susceptible to the virus at worst.
Links: Wikipedia page on antibody-dependent enhancement: en.m.wikipedia.org/wiki/Antibody-dependent_enhancement
I like the graphic from this article on ADE: www.the-scientist.com/infographics/antibody-dependent-enhanced-ade-immunity-39674/amp Red = first viral infection, and blue = second viral infection
Scholarly publication on SARS antibody-dependent enhancement in rhesus monkeys: www.ncbi.nlm.nih.gov/pmc/articles/PMC6178114/
One for MERS (abstract only): www.ncbi.nlm.nih.gov/m/pubmed/31826992/
And another of MERS antibody-dependent enhancement in rabbits: www.ncbi.nlm.nih.gov/pmc/articles/PMC5574614/ Of note in this one: “passive transfer of serum from previously infected rabbits to naïve rabbits was associated with enhanced inflammation upon infection.”
Dr. Peng, a 29 year old respirologist who died in Wuhan despite receiving serum therapy: k.sina.cn/article_5705191799_1540e517704000w223.html?from=science
Reinfection of Coronavirus in Japan: thehill.com/changing-america/well-being/prevention-cures/484942-japan-confirms-first-case-of-person-reinfected
Doctors warning about reinfection in China: www.nypost.com/2020/02/19/whistleblower-doctors-say-coronavirus-reinfection-even-deadlier/amp/
Bottom line: don’t get infected. If you do, you REALLY don’t want to get reinfected. This isn’t the flu.
Full disclosure: I work in an antiviral laboratory, and I have a lot more hope for remdesivir, Kaletra (lopinavir/ritonavir) and chloroquine.
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