If someone has a headache or feels a little out in the open after receiving a vaccine against COVID-19, it is common to hear them say something like “Oh, it means my immune system is working hard.” On the other hand, when people don’t notice any side effects, they sometimes worry that the shot isn’t doing its job or that their immune system isn’t reacting at all.
Is there a link between what can be noticed after a vaccine and what happens at the cellular level within the body? Robert Finberg is a physician specializing in infectious diseases and immunology in the University of Massachusetts School of Medicine. Explain how this perception does not match the reality of how vaccines work.
What does your body do when you get vaccinated?
Your immune system responds to the foreign molecules that make up any vaccine through two different systems.
The initial response is due to what is called innate immune response. This system activates as soon as your cells notice that you have been exposed to any foreign material, from a splinter to a virus. Your goal is to eliminate the invader. White blood cells called neutrophils and macrophages travel to the intruder and work to destroy him.
This first line of defense is relatively short, lasting hours or days.
The second line of defense takes days to weeks to get underway. This is the long run adaptive immune response. It is based on T and B cells of the immune system who learn to recognize certain invaders, such as a coronavirus protein. If the invader is found again, months or even years in the future, it is these immune cells that will recognize the old enemy and begin to generate antibodies that will overthrow him.
In the case of SARS-CoV-2 vaccines, it takes approximately two weeks to develop the adaptive response that provides lasting protection against the virus.
When you get the vaccine, which you will notice the first or two days is part of the innate immune response: the inflammatory reaction of your body, designed to quickly clean the foreign molecules that infringed the perimeter of your body.
It varies from person to person, but the degree of response to the initial response is not necessarily related to the long-term response. In the case of the two COVID-19 mRNA vaccines, more than 90% of people are immunized developed the protective adaptive immune response while less than 50% developed any side effects, and most were mild.
You may never know how well your body’s adaptive immune response is preparing.
The bottom line is that the proper functioning of the vaccine within the body cannot be measured based on what can be detected from the outside. Different people make stronger or weaker immune responses to a vaccine, but the side effects after the shot won’t tell you what salary you are. It is the second adaptive immune response that helps the body gain immunity from the vaccine, not the inflammatory response that triggers those first pains.
What are the side effects?
Side effects are normal responses to the injection of a foreign substance. They include things like fever, muscle aches, and discomfort at the injection site, and are mediated by the innate immune response.
Neutrophils or macrophages in the body notice vaccine molecules and produce cytokines, molecular signals that cause fever, chills, fatigue, and muscle pain. Doctors expect this cytokine reaction to occur every time a foreign substance is injected into the body.
In studies where neither recipients nor researchers knew which individuals received the mRNA vaccine or a placebo, approximately half of people aged 16 to 55 who received a vaccine against SARS-CoV-2 developed a headache after the second dose. This reaction may be related to the vaccine, but a quarter of people who received only one placebo also had a headache. Therefore, in the case of very common symptoms, it can be quite difficult to attribute them to the vaccine safely.
Researchers anticipate some reports of side effects. Adverse events, on the other hand, are things that doctors do not expect to happen as a result of the vaccine. They would include organ failure or severe damage to any part of the body.
The blood clots that triggered the US Johnson & Johnson vaccine distribution pause they are a very rare event, apparently occurring with a frequency of one in a million. It is still being investigated whether they are definitely caused by the vaccine, but if scientists conclude that yes, blood clots would be an extremely rare side effect.
Which component of the shot causes side effects?
The only “active ingredient” to Pfizer i Modern vaccines is the MRNA instructions indicating recipient cells to build a viral protein. But traits have other components that help mRNA travel inside the body.
To get the mRNA from the vaccine to the cells of the vaccinated person where he can do his job, he must evade the enzymes in the body that will naturally destroy him. The researchers protected the mRNA from the vaccine by wrapping it in a lipid bubble that helped it avoid destruction. Other ingredients in prey, such as polyethylene glycol, which is part of this lipid wrapper, can cause allergic responses.
If I feel sick after my shot, does this indicate strong immunity?
Scientists have not identified any relationship between the initial inflammatory reaction and the long-term response that leads to protection. There is no scientific evidence that someone with more obvious side effects from the vaccine is better protected from COVID-19. And there’s no reason why having an exaggerated innate response would improve your adaptive response.