- Coronavirus vaccines are indeed very effective in preventing hospitalization and death, but not as much against getting infected.
- Neutralizing antibodies generated in response to vaccines kick in nearly instantly and are therefore most effective in preventing infection. However, with the coronavirus, they wane with time and are less effective against the new variants, including Omicron, BA.4, BA.5, BA.75, etc.
- B-Cells and T-Cells are also generated in response to vaccines. They take longer to act, usually sometime after an infection occurs. However, they remain very robust over time and as new variants emerge, thereby protecting against severe and prolonged infection.
- Overall, vaccines continue to meet the fundamental Operation Warp Speed objective of protection from hospitalization and death. This protection is very significant, but no vaccine is 100%.
I’m sure we’re all familiar with the ongoing debate on whether the coronavirus vaccine will protect us and whether or not it’s worth getting. Some highly credible sources within the medical community say it is still our best first-line defense whereas others say it’s useless. There is also a lot of publicity to the effect of how the new variants evade vaccines and prior infection. And worse, the debate has clearly taken on a life of its own and, as the “yeas” and “nays” often align with one’s political party. So, why is there such a huge disparity and who do we believe? What is the ground truth, and how do we get to it?
The short answer is it depends on one’s expectations of the vaccine. If you want a 100% safeguard against contracting the coronavirus, testing positive, and/or developing even the mildest of symptoms, unfortunately, you are likely in for a disappointment. However, if your primary expectation is to avoid a severe coronavirus infection requiring hospitalization or leading to death, then I’m sure you will be pleased to know that the current vaccines still protect well against hospitalization and death, even with the new variants. Note, there is still a risk of severe illness/death, especially for those with underlying conditions and those who are immunocompromised. However, the risk of this happening with most healthy people is much lower than it would be if that same person remains unvaccinated.
I’m sure, from this, we can easily understand why so many people get confused or led to the wrong conclusions. Hence, my intent is to help clear up some of the confusion and help the reader understand – at least from a 50,000-foot view, how the coronavirus vaccine works and how/why it offers the protection level that it does.
The truth is coronavirus vaccines have always offered only limited protection from getting infected and getting sick. This already marginal protection from getting infected/vaccinated has proven to wane quickly with time, and it seems to wane even more quickly with nearly each new major variant. Yet, by contrast, the protection vaccines provide against getting severely ill with COVID or dying of COVID is holding up quite well over time and with new variants. So why the disparity between protection from initial infection and protection from hospitalization and death?
This partial success can be easily explained via a basic understanding of how the vaccines and our immune systems work. In essence and as many of us are aware, vaccines simply “teach” our immune system to recognize a coronavirus infection and how to combat it. Our immune systems protect us from various infections/illness by having the 3 main components of our immune systems working together. Fundamentally, what nearly all – if not all – vaccines do is exercise each of those components as separate components and in unison in the same or similar ways that actual infections do.
Thus, I will start with an overview of our immune systems’ components and how they work. Then, I will talk about how the vaccines interact with our immune system and offer insight into connecting the dots and translating all of this into what we should and should not expect of vaccines.
The 3 Main Components of the Human Immune System and How They Work
We are born with a set of antibodies. They are always present at some level and are dispersed within our blood and tissues. They provide the first line of defense against an antigen/intruder. Because they are always present, their response is nearly instantaneous. It usually takes only minutes to just a few hours for our bodies to mount a substantial antibody response. Foreign substances that our antibodies directly attack are called antigens. They include the types of germs that are common in our environment. Since our antibodies are always present in our blood, they will immediately activate and pounce on a newly-introduced antigen, usually within minutes or hours.
An antibody response occurs via phagocytosis, which is a major mechanism used to remove disease-causing germs, called pathogens, and cell debris. The ingested material is then digested in the phagosome, which is a vesicle ) (AKA membrane) formed around a particle engulfed by a phagocyte via phagocytosis. A phagocyte is simply a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles. This is what makes antibodies so effective in preventing and fighting an infection.
Some antibodies are “general purpose” and will thus go after nearly any antigen that they encounter. Other antibodies specifically target a particular antigen type. The “specific” antibodies are actually formed by our B cells, in our B cells’ response to the pathogen. (See below for more information on B cells.) So, they are present only sometime after an initial infection or vaccine occurs.
Innate Versus Adaptive Immune Response
When the body is first invaded by a pathogen, two things happen: First, the non-specific antibodies that are always present in our blood and tissues will immediately engage and fight the pathogen. This is a key part of what is known as the innate immune response. We are born with such mechanisms. Second, the body’s immune system will mount what we call an adaptive immune response. This occurs simultaneously with the innate response, and it targets the specific pathogen that has invaded the body. Pathogens are live organisms that contain antigens in the form of proteins that are on the surface of a given germ cell. They include bacteria and viruses, including the coronavirus.
The adaptive response engages B cells and T cells (see below for descriptions of each) in addition to the antibodies already present in our blood. Our bodies recognize that a particular antigen should not be there, and it builds B cells and T cells that will remember how to fight a specific pathogen if it infects us again in the future. The B cells and T cells provide a very strong response that are often much stronger than the initial innate response; however, there is a downside. It can take up to several weeks after infection before they will fully recognize and fight a particular antigen. As they kick in, the greater number of cells of a given pathogen, the greater the B cell and T cell response. B cells also produce antibodies that are specific to a particular pathogen.
Hence, with an adaptive response, the antibodies provide an immediate response. That immediate response is a combination of the antibodies present as part of the innate response plus those produced by B cells, which are a result of a prior adaptive response. The T cells also fight the pathogen very aggressively; however, like the B cells, it usually takes a few days for them to mount a significant response.
Now, let’s talk about next two major components of our immune response to the coronavirus: B cells and T cells.
B cells, AKA “memory” cells, are a type of white blood cell, or lymphocyte that is activated when it encounters an antigen in the blood. It then, in turn, formulates specific antibodies that will attack that particular antigen. Hence, B cells are the “recipe book” that remembers the specific antigen and respective antibody of the pathogen that was in the person’s blood as a result of a previous infection or vaccination. After the infection, a low level of B cells will remain in the blood for a long time. As soon as they encounter that same antigen again, they will go right to work producing the specific antibody that will attack that particular antigen. Because it already knows the “recipe” of the antibody, it usually takes much less time for the B cells to produce the needed antibodies after the vaccine or initial infection. End result: an arsenal of pathogen-specific antibodies that supplement the non-specific antibodies that are always present. However, these supplemental/specific (unlike the non-specific/innate) antibodies tend to wane with time.
T cells are lymphocytes that come in two forms. 1) “helper” cells aid other immune cells by releasing cytokines. Cytokines control and regulate the body’s inflammatory response. 2) “killer” cells, which directly attack and kill cells that are infected with a particular pathogen or cancer cell. Combined, both types of T cells pose an extremely strong immune response. However, like B cells, they take time to materialize after an infection.
Combined Response of These 3 Components
As you can tell from the above, these 3 components (antibodies, B cells, and T cells) all work together to fight off a given infection. The antibodies (both specific and non-specific) provide the immediate response, and the B cells and T cells provide a much stronger response, but it takes time for them to mount up that response, especially upon first-time exposure. Also, the “specific” antibodies tend to wane with time.
When a virus like the coronavirus infects us, it starts to quickly reproduce and spread while, simultaneously, our immune system is ramping up its B cells and T cells to fight it off. This creates a “race” condition between the virus and these two components of our immune systems.
If there are already enough antibodies present in the blood and tissues upon initial infection, they will annihilate – or at least neutralize – the virus/bacteria before it has a chance to replicate enough to produce symptoms. This is what prevents us from getting sick at all – the best-case scenario.
However, in reality, such is often not the case. The initial antibody response might slow down the spread of the pathogen but not be intense enough to stop it. This leads to a race-to-the-finish-line situation between the pathogen spreading and the B cells and T cells mounting their response. The further along the spread before these special lymphocytes kick in along with more antigen-specific antibodies produced by the B cells, the more severe the disease is likely to be.
How Vaccines Help
Vaccines are instrumental in fighting pathogens, including the coronavirus, in that they tilt the race condition in favor of our immune systems. They do this by introducing small amounts of either an attenuated (live but unable to reproduce) version of the pathogen, the dead pathogen (with antigens intact) or parts of the pathogen (again, with antigens intact). Because the pathogen cannot spread, the aforementioned race condition doesn’t exist. Thus, it doesn’t matter how long it takes for the B cells and T cells to “teach” our immune systems how to mount a full-up immune response. In the case of the coronavirus and several other vaccines, it takes about 2 weeks or longer to mount a full response, and that’s OK.
However, once a full-up response occurs the first time, a certain number of antibodies, B cells, and T cells specific to this pathogen remain in our blood. The B cells already know the “recipe” of the antibodies and other responses needed to fight the pathogen. Thus, the timeline for the B cells and T cells to mount their full response a second time is much shorter. This helps a lot, in that it will all but guarantee that the immune system will win the race to avoid severe illness (assuming one has a healthy immune system), should our bodies actually become infected with the same pathogen.
Why Are Vaccines Against Some Diseases Are More Effective Than Vaccines Against Other Diseases?
The reason is twofold:
- With some diseases, the antibody count in our blood remains high for longer periods (specific antibodies only). This is due to how our bodies react to the pathogen, regardless of whether it’s introduced via vaccine or actual infection. This provides a more intense first-line immune response that is often enough to annihilate the disease – or at least impede it – before it can spread, thereby preventing any symptomatic infection.
- Some diseases spread more rapidly than others. For the slower spreading ones, the B cells and T cells have more time to mount an adequate response to annihilate the disease before it causes symptoms.
How Does This Relate to The Coronavirus Vaccines?
Unfortunately, the coronavirus, itself, presents the worst of both worlds. Our body’s coronavirus-specific antibody count drops off fairly sharply after infection or vaccine, and the virus multiplies/spreads extremely rapidly. Thus, especially with the newer variants, the coronavirus often wins the race to symptomatic infection despite the vaccine’s best effort to preclude this.
However, thanks to the B cells being pre-programmed by the vaccine, the B cells and T cells still engage soon enough (in most cases) to prevent the coronavirus from spreading so much/so fast that it causes severe illness that requires hospitalization. To me, this alone is a huge upside and is compelling reason enough for us to get the vaccine.
Coronavirus vaccines often don’t prevent us from getting sick with the coronavirus. However, such illness is usually milder than it would be without vaccination and is much less likely to progress to the point that one must be hospitalized or worse.
This is really the primary objective of the vaccines and is why we can deem the coronavirus vaccine program, as developed under Operation Warp Speed, a success despite the fact that vaccines often don’t prevent illness altogether.
Upon approximately 2 weeks after receiving a coronavirus vaccine, we should not expect much protection from the common cold/flu like symptoms of the coronavirus. However, we should know that we have significantly greater protection against severe infections that might otherwise land us in the hospital or worse. This is not enough protection for us to completely let our guard down, but enough to breathe a sigh of relief and resume our normal life activities.
For additional information, please check out the “Understanding The Coronavirus Vaccine” page on my website.