Could exposure to the coronaviruses that cause the common cold help protect against COVID-19?

[DGRossetti]

www.timesofisrael.com/scientist-posits-wild-hypothesis-that-cross-immunity-could-slow-pandemic/

PARIS (AFP) — Could exposure to the coronaviruses that cause the common cold help protect against COVID-19? Is herd immunity closer than previously thought?

As nations lift lockdowns and experts worry about a potential second peak in cases, our ability to ward off infection is one of the hottest topics of scientific debate.

Ever since it became apparent that children were less vulnerable to COVID-19 early in the pandemic, scientists have speculated that the regular spread of benign viruses in places like schools could have bolstered their immune response to the latest coronavirus.

Now the idea of “cross immunity” among the broader population is gaining some ground.

In a recent post on Twitter, Francois Balloux of University College London noted an “intriguing” lack of an immediate resurgence in COVID-19 cases following the easing of lockdowns in several countries.

Among the possible explanations, he noted, were seasonality and enduring social distancing practices.

But he posited a “wilder” hypothesis as well — that a “proportion of the population might have pre-existing immunity to #SARSCoV2, potentially due to prior exposure to ‘common cold’ coronaviruses.”

Balloux said that might explain issues like cases where there is no transmission between spouses.

Earlier this month, an American study in the journal Cell suggested between 40 and 60 percent of the population could be immunized against COVID-19 without ever being exposed to it.

(contd)

that's weird, I don't reckon that the viruses are that closely related.

Getting exposed to ... chickenpox doesn't protect you from herpes simplex, I bet. Even though they are both herpes, as I understand it.

I get impression there are a lot of bad ideas floating around. That part I easily believe.

Just puttin' it out there ...

I’ve been thinking this for some time. It’s never shown signs of ripping through an entire population in any country, just a proportion of them before petering out, which is suggestive of some sort innate immunity for some. It would explain the difference in severity.

I had a stinking cold a couple of weeks prior to my suspected COVID. I've always wondered if it was another Coronavirus that gave me that cold and gave me some antibodies to help me fight COVID as my only symptoms were fever and loss of smell/taste, no cough or breathlessness

I've read this several times in various scientific periodicals, it's an idea that's seemingly gaining traction.

I posted this on another thread but I am no expert and this is no time to drop our guards just yet.

I think predictions based on models have assumed zero immunity and 100% of the population is vulnerable to this. That's now looking very wrong.

They have found that sars-cov-2 specific t cells are cross-reactive which are present in about 40-60% of the population due to previous common cold infections, probably inside the last couple of years. The documents are mostly studies which are a little complicated but there are some articles which spell it out in a way which is easier to understand. A specific as yet unknown common cold virus which is a coronavirus (there's only 4 of them that are endemic) provides this immune response and it's very widespread. They don't know which of the colds does it but I'm sure there are many people working on this in labs around the world right now.

Could one of the 4 existing HCoVs (common cold coronaviruses) function as an effective vaccine? My suspicion is that it could and this is what explains the very large number of very mild and asymptomatic cases. So effectively we are almost up to herd immunity with this cross-reactive response - obviously, too early to call celebration but enough anecdotal and scientific evidence appearing to give a good push in that direction. I suspect by the end of the month given all the apparent 'lockdown's over' behaviour already exhibiting then we will be able to call this much better.

www.cell.com/cell/pdf/S0092-8674(20)30610-3.pdf

Herd immunity though is not the same as what is alleged here by the Italian doctors. Herd immunity is when a sufficient number of individuals in the population (somewhere between 60% and 80%) have either been vaccinated or survived the disease and are carrying sufficient antibodies to combat any future infection.

What is being described here is the alleged weakening of the virus and its infectivity. If true, several issues arise. 1. This weakening can change as the virus mutates. 2. The form that is weakening in Italy is clearly not the one that is still killing people in the USA and elsewhere in large numbers. Given the lack of international travel, it is not possible for the weaker version to predominate. 3. Now that we have experienced what a virus that comes from animals can do to us, even if this virus dies out for whatever reason, we should be preparing now for the next one.

So viral weakening and effective herd immunity that would be a double good win.

Surprising theory (there was another theory much earlier that having had a related but different coronavirus could trigger an excessive immune response, so quite the opposite!), but if true, would be great news.
Time will tell.