Can someone help me understand the difference between this and other vaccines? From what I know, the COVID-19 vaccine is only effective in reducing symptoms for those who get inoculated. Is it accurate to say this vaccine does not prevent infection or help develop an immunity? I just do not understand how vaccines work. Would love a (peer-reviewed) source or sources I could read to brush up.
This is not a political or bait post I really am looking for some signal in all the noise.
Vaccines never quite prevent infection. What they do is give the immune system a head start so they can overtake the infection early. Hopefully early enough to prevent symptoms, and ideally early enough to prevent transmission.
But just how early the immune system can win will depend on the strength on the immune reaction and the specifics of the virus. So for this specific one we don’t yet know whether it’s early enough to prevent subsequent transmission.
For example if transmission would require coughing and you never develop a cough, then there probably won’t be much transmission. But the potential for pre-symptomatic transmission suggests that it won’t be that simple, and while in theory this should reduce transmission it probably won’t eliminate it entirely.
As I recall from the news around the time the Pfizer vaccine was approved, the results from the people given the vaccine (vs. the placebo) was that it both reduced the rate of people who tested positive for the virus, AND reduced the severity of the symptoms to the point that the hospitalization rate was way down and the death rate was zero.
These are basically the same as the 'subunit' type of vaccine, with the difference being that your body produces the subunits directly through instructions in the mRNA that is in the vaccine. In this case the mRNA in the vaccine instructs your cells to create copies of the 'spike protein' portion of the SARS-CoV-2 virus that causes COVID-19. After being created by your own cells, these proteins enter the blood stream, trigger an immune response and ultimately immunity to viruses having that spike protein.
This is extremely targeted immunity vs. natural immunity generated by an infection, in which your body will create antibodies for all sorts of proteins in the virus. The broader resistance from natural immunity sounds good, and does have some benefit, but it also increases the risk of making your body react to its own tissues, creating an autoimmune condition. On the other hand, one potential downside of the mRNA vaccination is that if the virus mutates the spike protein sufficiently to resist the antibodies generated by the vaccine, you're back to square one.
> From what I know, the COVID-19 vaccine is only effective in reducing symptoms for those who get inoculated. Is it accurate to say this vaccine does not prevent infection or help develop an immunity?
As others have mentioned immunity does not mean 'zero infection', it simply means that your immune system is primed to stop the infection quickly by having antibodies for the spike protein.
There are a variety of COVID-19 vaccines either already approved or in the pipeline in various countries. Only some of them are mRNA vaccines, notably the one from Moderna. Others are based on older technology.
Cool, so the spike protein "factory" creates facsimiles of the actual SARS-CoV-2 spike protein, which then becomes a trigger to the immune system to create antibodies for that specific virus/spike protein combo.
The mRNA approach to vaccines seems to be a leaner, meaner, 2.0 version wherein instead of injecting a virus ut totum the vaccine-development-wizards have developed it to use just enough of the original virus code to trigger the immunological response, bolstering our defenses, and thereby increasing resistance to the thing "in the wild."
Would this apply to other coronaviruses, such as "common cold" type vaccinations? Were there specific discoveries in 2020 that will open the floodgates to better influenza protection? </rhetorical>
These types of responses are really helpful, and help me to get back into a rational framing of the subject - rather than fielding psychological noise from headlines and sub-informational news pieces.
It’s broader than that actually, this is a generalized protein factory.
This is how mRNA is created by the cells in your body to create the proteins needed to keep you alive (aka transcription): https://youtu.be/SMtWvDbfHLo
This is how mRNA is then used to create proteins, either from strands manufactured by your own cells, those coming from viruses that have infected your body, or from mRNA vaccines (aka translation): https://youtu.be/TfYf_rPWUdY
Not directly related, but here is an amazing video showing how HIV infection works, including parts you will now recognize from the above: https://vimeo.com/260291607
Well I guess that depends on what you mean by “true immunity”. If you mean not a single cellular infection, then that is ridiculous since true immunity doesn’t exists.
If instead you mean that you develop no symptoms, and cannot pass on the virus, then they indeed can and do (which is why r naught drops).
Now obviously if your “high viral load” is being literally bathed in viruses... then ok. But for many situations, typical viral load and even high viral load situations as seen in health care settings, many vaccines would qualify as giving large percentages of people “true immunity” in the sense of no symptoms and no viral shedding.
Another thing vaccines can do is prevent illnesses caused by toxins. In those cases antigens of toxic compounds generate antibodies to incapacitate a toxoids effect on the body, for example the tetanus and diphtheria vaccines or vaccines against rattlesnake venom.
These covid posts on hn are some of the most hostile threads I've seen on the internet. Between the intense emotions, conspiracy theories where people thinks they're constantly under attack, and various frustrations. Just don't take it personal. Or honestly dont bother with covid threads on this site. I'd treat them as read only and get your info elsewhere
Your body has two types of immune response, one called an innate immunity, which basically is programmed to attack certain types of pathogens at birth, and another an adaptive or acquired immunity. Vaccines target the adaptive immunity.
If we only had an innate immunity, viruses and other pathogens would learn to bypass it by hiding or disguising themselves in various ways. In order to counter this, our bodies constantly learn to recognize new pathogens. This is done by breaking down viruses into protein parts called antigens and creating antibodies that bind to those parts. Think of it like a lock and key.
Viruses typically have many proteins that can serve as these antigens on the surface of their cells. Many of these protein structures are actually used by the virus to bind to cells in our body and enter them.
Once antibodies to those antigens are being produced, they’re able to lock onto those surface structures and interfere with a viruses ability to function.
So a vaccine is simply a way to introduce those antigens and surface binding proteins in order to cause your body to generate an antibody immune response.
Another key component is that once your immune system creates antibodies, it “remembers” them through certain memory cells that are able to quickly produce the same antibody when needed at a later date.
Now all that sounds pretty simple, but the details get complicated, which is why vaccine effectiveness varies. Oftentimes certain types of viruses change their outer proteins so often, that a vaccine targeting one strain produces an immune memory that doesn’t work well with the next mutation.
Or other times the antibodies only bind to certain proteins that only partially interfere with virus infection. Or in some cases the way the vaccine is produced means that the antigens change subtly during the process making them less potent for good antibodies.
These new COVID vaccines are actually a method if introducing specific and accurate antigens to our immune system in a novel way. In this case it’s a bit of RNA that causes our cells to generate the antigen proteins themselves. It has the promise of being able to produce antigens of greater number and specificity than other methods. It’s basically using the same process as many viruses themselves (rna getting our cells to produce proteins) meaning our immune system is primed to take advantage and produce stronger immunity.
So the short answer is these vaccines are likely to produce strong and lasting immunity to the coronavirus they are targeting. What is unclear however is how fast this new strain of coronavirus will mutate into strains requiring more yearly shots to deal with changing antigen profiles (like the annual flu).
So the unknown is simply how this virus will evolve... if we’re lucky mutations that significantly change the surface antigens targeted by these vaccines will also mean the virus either becomes less contagious or less deadly.
If you’re truly interested I highly recommend this book on how the immune system works, full of excellent sources.
This I did not know - so basically there's a class of pathogens we have protections for at birth, and others we have to learn by exposure.
Antigens act as metadata of sorts from which our immune system can use to develop response mechanisms, do these antigens mean "permanent upgrade," in terms of our immune system recognizing it? (Yes, memory cells - cool!)
Just ordered a copy of the recommended book from my local library, thank you for the February reading list.
You got it! The memory cells seem to be able to last many decades through special cellular processes.
Hope you like the book. It’s a fascinating read. My favorite part is when he describes how the immune system is basically able to fuzz test for antibodies. It recombines and quickly mutates its own dna to generate way more antibody types than otherwise would be possible.
> From what I know, the COVID-19 vaccine is only effective in reducing symptoms for those who get inoculated. Is it accurate to say this vaccine does not prevent infection or help develop an immunity?
These statements are not accurate, but I think that there may be a misunderstanding with the discussion of whether the vaccine prevents symptomatic spreading.
First, to the second part of your statement, no vaccine really "prevents" infection. A vaccine primes the immune system to fight an infection, but the immune system typically only recognizes the attack once at least some cells have been infected and start producing more viruses.
However, being vaccinated typically means that your body will wipe out the virus before it has a chance to take hold and make you sick. But this doesn't mean it is just "reducing symptoms" the way, say, Sudafed reduces nasal congestion without attacking the cold -- being vaccinated really does mean that your body's defenses are armed to fight and destroy the virus the moment it invades. So it's completely wrong to say it simply "reduces symptoms."
What I think you're confusing this with is that scientists are saying that there is still a chance that you can become infected and become an asymptomatic spreader, even if you don't get sick.
The scientists aren't quite sure if this is the case or not, because it wasn't measured in the large vaccine trials. It's very likely that the vaccine at least reduces your ability to spread the virus, if not completely eliminates it, because that's the way most vaccines work. However, the reason the question is still unknown because certain respiratory diseases can still be spread after vaccination, because those viruses can sometimes replicate within the mucosal tissues in the nose, "hiding" from the body's main immune system.
As for the rest, I haven't really gotten a straight answer on the vaccine. Seems there are people who say it is the best thing since slice bread, and others who say it will be about as useful as the yearly flu vaccine. No one actually knows.
