Long Term Side Effects of mRNA Vaccines Unlikely, Conclusion

Conclusion: A Different Category of Possibility

Having gone through all ways that I could think of mRNA vaccines could possibly cause long-term complications without those complications arising fairly soon after administration, I could not find any.  I couldn't even think of a mechanism by which such a long-term complication could happen.

This is not the same thing as a proof that such a thing couldn't happen.  "I thought about it very hard and I couldn't think of a way it could happen" isn't a proof--maybe you just don't know enough to think about the right things!  No one could claim to know enough about the human body and the immune system to be able to understand absolutely everything any therapeutic could do.

But that's why the title of this series of posts was "Long Term Side Effects of mRNA Vaccines Unlikely": unlikely, not impossible.  "Unlikely" is the limit of what we can prove at this point.

What I think this series does prove is that the risk of such a long-term complication lies in the realm of the true "unknown unknowns".  Especially considering how such a long-term complication has never before come up from a new vaccine, it would be a risk from out of left field--something truly new and unforeseeable.  

I think this is an important result that should have consequences on our own decision making.  One way of dealing with risks is appropriate if there are known possibilities of something bad happening, but if all you have is doubts that you know enough about some thing--even after all the experts have done everything they can to understand every possible risk about it--then it is not appropriate to consider this thing a risk in the same way.  The risk exists in a different category of possibility.

What I mean here might become more clear when you compare the risk of the new vaccines against some other things.

Comparative risk

Compared to Covid-19

Compared to the risks associated with getting the new vaccines, Covid-19 has many risks of long-term consequences.  There are flat-out "knowns": permanent lung damage and heart tissue scarring are the two most likely long-term consequence that we know about, but there are a whole host of other things that are known to happen to sufferers of severe Covid as well.  Then there are "known unknowns", such as the possibility of heart tissue damage even from mild cases, and the potential for nerve tissue damage (given that we see Covid has neurological side effects which may or may not involve permanent damage to nerve tissue based on what we know so far).

Then there are the "unknown unknowns".  And here, Covid has all of the same potential to cause issues that the vaccine does.  For the vaccine, by far the most likely class of problems from which some unknown long-term complication could come is auto-immune issues.  But everything that I identified as a potential for causing problems from the vaccine, the virus also does.  

Suppose there were some antibody that the immune system generates in response to the spike protein from the vaccine that ultimately causes some sort of long-term problem.  Well, not only does an actual infection from the virus also produce that spike protein, it 

1. produces the whole virus as well (giving the immune systems more features to react to and hence more chances to produce some hypothetical dangerous antibody), 
2. it produces them throughout the body in many more types of tissue as it spreads around (thus multiplying the number of possible interactions between the foreign invader and different types of human cells and exponentially increasing the chance of a human cell getting targeted by the immune system), and 
3. it produces them for far longer than the few days that the vaccine exists in the human body.  This length of time in which the immune system is in a heightened "battle mode" thus also increases the chance which I mentioned for some over-zealous member of the immune system to trigger an immunity against the wrong thing.

Some people have been nonchalant about the risks of catching Covid-19, but very hesitant to take the vaccine.  This makes no sense whatsoever.  Not only does catching Covid-19 carry with it all of the same risk of the unknown that the vaccine does, it has whole classes of risk--of things both known and unknown--which the vaccine does not.  I can understand the desire to avoid both things, but to consider the virus a relatively safe known compared to the unknown risk of the vaccine is pure ignorance or irrationality.

Compared to other vaccines

Most of what I have talked about in these series of posts applies similarly to a lot of other vaccines.  But not all, and it would be worth discussing those ways in which mRNA vaccines are likely to be safer than the more traditional types of vaccines.  This would be a good topic for a dedicated post, in fact.

The only specific thing I'm going to mention here is how the most common type of traditional vaccine works, which is by taking the actual virus and neutralizing it in some way, then injecting the deactivated virus into the body, thus eliciting the immune response.  Whatever way the virus is neutralized, it involves serious damage to the viral particles--by necessity, because "neutralize" is another way of saying "destroy the basic functioning capacity of the virus".

What this means is that a traditional vaccine involves the injection of randomly damaged microscopic material into your body: at the cellular level, billions of individually mangled viruses, possibly with weird broken structures and possibly with randomly scrambled RNA from radiation.  Normally this turns out OK, but there have been instances in the past where the damage to the virus itself has been suspected of causing the antibodies generated in response to them to be defective, and even possibly dangerous (read up on a failed RSV vaccine from the '60s for this, though the "damaged virus" theory is currently out of favor).

It has to be admitted that mRNA vaccines have a much cleaner, more predictable path towards generating immunity, at least in theory.  It has always been the theory that mRNA vaccines will be inherently safer than older vaccines due to the very targeted and controlled antigen that they generate and the very precise way in which this antigen is produced.

Up until recently, this idea has been just theory, but I think it is worth understanding that mRNA vaccines have some key theoretical safety advantages to older forms.

Final Conclusion

No one can claim perfect knowledge of the future, but when it comes to the long-term safety of the new vaccines, it is at least a very safe bet that they will turn out to be completely fine.  I did not hesitate to get the vaccine myself, and neither should anyone else.