Firstly, a lot of people appear to think that anyone who does not have SARS-CoV-2 antibodies has no immunity against the virus; this is false.
Anyone who has been exposed to other coronaviruses (some of which are deemed to be "common cold" viruses, though not all "common cold" viruses are coronaviruses; many are actually rhinoviruses ) will likely have at least some immunity; depending on the strength of the persons immune system, and the dose of infection and other factors, it is very possible that many people can fight off SARS-CoV-2 without experiencing severe symptoms, or any symptoms at all, without having to produce any antibodies.
Here are some interesting articles; firstly to understand a bit more about T-cells:
The article goes on to say:
While a lot of the facts remain unknown, it's increasingly obvious - and undeniable - that the unexposed population has at least some immunity to SARS-CoV-2 and therefore the claims that some people make, along the lines of "only 7% (or whatever) of the population are immune" is totally untrue; that said we do not know exactly what the actual percentages are, and based on the evidence available so far, it is extremely likely to vary by country/region and other population factors.
Here is a fascinating video; if anyone is particularly interested I'd recommend watching the full thing, but if you are short for time, just watch the first 10 mins or so, the bit around the 1 hour mark, and the summary at the end:
I really do recommend people watch this, or at least part of it!
For anyone unable to access the video, a brief summary is that evidence is emerging that strongly suggests there are many 'categories' of immunity, but the exact proportions who are immune is not yet fully known.
The disgraced Professor Ferguson's model - which was proven to be deeply flawed - assumed that no-one had any immunity; see numerous existing threads where this has cropped up (e.g. https://www.railforums.co.uk/threads/coronavirus-how-scared-should-we-be.204710/page-4#post-4595085 and https://www.railforums.co.uk/threads/should-our-lockdown-have-been-harsher-stricter.205224/page-2 among other threads). We can be confident this assumption was completely false, though we cannot be confident as to exactly how many people are already immune.
Edit: Now I've learnt a lot more about how the body's immune system works, I now have a much better idea of the answers to a question I asked back in April: https://www.railforums.co.uk/threads/am-i-lucky-with-viruses.203890/
Anyone who has been exposed to other coronaviruses (some of which are deemed to be "common cold" viruses, though not all "common cold" viruses are coronaviruses; many are actually rhinoviruses ) will likely have at least some immunity; depending on the strength of the persons immune system, and the dose of infection and other factors, it is very possible that many people can fight off SARS-CoV-2 without experiencing severe symptoms, or any symptoms at all, without having to produce any antibodies.
Here are some interesting articles; firstly to understand a bit more about T-cells:
Why Immunity to the Novel Coronavirus Is So Complicated
Some immune responses may be enough to make a person impervious to reinfection, but scientists don't yet know how the human body reacts to this new virus
www.smithsonianmag.com
The article also goes on to say:T cells—another subset of the adaptive response—are often left out of conversations about immunity.
“You can’t have a great antibody response without T cells,” says Akiko Iwasaki, a virologist and immunologist at Yale University. Among a slew of helpful functions, T cells help young B cells mature into antibody-making machines. “These things really go hand in hand.”
T cells are also formidable fighters in their own right. In a bid to stop the spread of a pathogen throughout the body, some T cells will trigger infected cells to self-destruct. Others linger after an illness has resolved, patrolling tissues so germs can’t reestablish a foothold. (One of the reasons that HIV is such a devastating diagnosis is that the virus destroys some of the body’s T cells.)
Studies of other coronaviruses, including the ones that cause SARS and MERS, show that T cells play integral roles in stamping out sickness...
And here is another article, which talks about how there appear to be different levels of immunity in different populations:...That doesn’t mean people are doomed to experience the same diseases over and over. “The word ‘immune’ makes it sound like the virus gets close to your body, hits a wall, and has to turn away and go find someone else,” says Allison Roder, a virologist at New York University. But even partial protection from the immune system will curtail the amount of pathogen in a person’s body, and, by extension, the likelihood of transmission..."
Are we underestimating how many people are resistant to Covid-19?
Scientists are racing to work out why some populations are more protected against Covid-19 than others
www.theguardian.com
One thing seems clear: there are many reasons why one population is more protected than another. Theoretical epidemiologist Sunetra Gupta of the University of Oxford thinks that a key one is immunity that was built up prior to this pandemic. “It’s been my hunch for a very long time that there is a lot of cross-protection from severe disease and death conferred by other circulating, related bugs,” she says. Though that cross-protection may not protect a person from infection in the first place, it could ensure they only experience relatively mild symptoms.'
The article goes on to say:
In a paper published in Cell on 14 May, researchers at the La Jolla Institute for Immunology in California reported that T cells in blood drawn from people between 2015 and 2018 recognised and reacted to fragments of the Sars-CoV-2 virus. “These people could not have possibly seen Sars-CoV-2,” says one of the paper’s senior authors, Alessandro Sette. “The most reasonable hypothesis is that this reactivity is really cross-reactivity with the cousins of Sars-CoV-2 – the common cold coronaviruses which circulate very broadly and generally give rather mild disease.”
The finding supported an earlier one from a group at the Charité hospital in Berlin, detecting T cell reactivity to proteins in the Sars-CoV-2 virus in 83% of Covid-19 patients but also in 34% of healthy volunteers who had tested negative for the virus itself....
While a lot of the facts remain unknown, it's increasingly obvious - and undeniable - that the unexposed population has at least some immunity to SARS-CoV-2 and therefore the claims that some people make, along the lines of "only 7% (or whatever) of the population are immune" is totally untrue; that said we do not know exactly what the actual percentages are, and based on the evidence available so far, it is extremely likely to vary by country/region and other population factors.
Here is a fascinating video; if anyone is particularly interested I'd recommend watching the full thing, but if you are short for time, just watch the first 10 mins or so, the bit around the 1 hour mark, and the summary at the end:
For anyone unable to access the video, a brief summary is that evidence is emerging that strongly suggests there are many 'categories' of immunity, but the exact proportions who are immune is not yet fully known.
The disgraced Professor Ferguson's model - which was proven to be deeply flawed - assumed that no-one had any immunity; see numerous existing threads where this has cropped up (e.g. https://www.railforums.co.uk/threads/coronavirus-how-scared-should-we-be.204710/page-4#post-4595085 and https://www.railforums.co.uk/threads/should-our-lockdown-have-been-harsher-stricter.205224/page-2 among other threads). We can be confident this assumption was completely false, though we cannot be confident as to exactly how many people are already immune.
Edit: Now I've learnt a lot more about how the body's immune system works, I now have a much better idea of the answers to a question I asked back in April: https://www.railforums.co.uk/threads/am-i-lucky-with-viruses.203890/
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