Naked Science Forum
Life Sciences => Physiology & Medicine => COVID-19 => Topic started by: nudephil on 22/04/2020 17:45:57
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We got this question from Adam:
Is there a potential risk that, for some individuals, a coronavirus vaccine might lead to a harmful immune response to subsequent COVID-19 infection?
Can anyone answer?
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I dont know but its a good question and intrigues me.
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It's impossible to know, because we don't know what would be in any vaccine.
However, if this hypothetical works the way most vaccines do, then it will contain molecules that are part of the virus- typically parts of the shell (but no DNA/ RNA, so it's not "infectious".
And whatever bit of the viral protein they use to trigger that response, it will be present in the real virus.
So, any effect that the vaccine might have could also happen as a result of the virus (which contains the same proteins etc.
In time it's likely that nearly everyone will be exposed to the virus.
So they will be exposed to whatever the vaccine's made of.
So, if there are any problems triggered by the vaccine, those same problems are likely to be triggered by the virus itself.
The obvious difference is that the virus kills quite a lot of people, and the vaccine won't. (Though there's the inevitable risk of an allergic reaction).
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We got this question from Adam:
Is there a potential risk that, for some individuals, a coronavirus vaccine might lead to a harmful immune response to subsequent COVID-19 infection?
Can anyone answer?
There is no evidence yet for this but experience with attempts to generate a vaccine to the original SARS virus suggests this is a real possibility. Although no vaccine was actually ever fully developed to SARS because of funding issues, various approaches were examined in mice. These approaches ranged from killed virus to recombinant subunits. All generated protective antibodies but they also resulted in allergic reactions in the lungs upon subsequent challenge with virus. The pulmonary damage was seen in all mice and was severe in some.
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We got this question from Adam:
Is there a potential risk that, for some individuals, a coronavirus vaccine might lead to a harmful immune response to subsequent COVID-19 infection?
Can anyone answer?
There is no evidence yet for this but experience with attempts to generate a vaccine to the original SARS virus suggests this is a real possibility. Although no vaccine was actually ever fully developed to SARS because of funding issues, various approaches were examined in mice. These approaches ranged from killed virus to recombinant subunits. All generated protective antibodies but they also resulted in allergic reactions in the lungs upon subsequent challenge with virus. The pulmonary damage was seen in all mice and was severe in some.
That's interesting.
Got any references?
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The ideal vaccine will generate a high level of antibodies which:
1. Bind to the virus coat
2. Deactivate the virus penetrating human cells
3. Attract the immune system
4. Destroy the virus
5. Ramp up production of immune cells which are looking for this virus
However, if the vaccine triggers a reaction to the wrong part of the virus coat, it can attract the immune system without deactivating the virus. This could result in the virus affecting the immune system.
- You may not detect this lack of virus deactivation if you just look for a good antibody response after vaccination.
It is also possible that after vaccination, exposure to the live virus triggers an overactive response to the virus; in this scenario, the immune system does more damage than the virus itself.
- That's why safety and effectiveness are both tested in a sequence of larger and larger trials, in "normal" vaccine development
- But the current situation is hardly "normal" - it is affecting "Western" countries, too!
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We recently published a piece on the coronavirus vaccine being developed by the University of Oxford team, based on a chimp adenovirus vector. This is regarded as a safer bet.
https://www.thenakedscientists.com/articles/science-features/covid-19-vaccines
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We recently published a piece on the coronavirus vaccine being developed by the University of Oxford team, based on a chimp adenovirus vector. This is regarded as a safer bet.
https://www.thenakedscientists.com/articles/science-features/covid-19-vaccines
How does the identification of the corona proetin spike and the over reaction of the immune system tally Chris ?