If someone gets a headache or feels a little under the weather after receiving a COVID-19 vaccine, it’s common to hear something like “Oh, that just means my immune system is working really hard.” On the other hand, if people do not notice any side effects, they are sometimes worried that the shot is not doing its job, or that their immune system is not responding at all.
Is there a connection between what you may notice after a vaccine and what happens at the cellular level in your body? Here’s what you need to know.
What does your body do when you get a vaccine?
Your immune system responds to the foreign molecules that make up any vaccine via two different systems.
The initial response is due to the innate immune response. This system is activated as soon as you see cells that you have been exposed to foreign material, from a splinter to a virus. Its purpose is to eliminate the intruder. White blood cells called neutrophils and macrophages move to the invader and work to destroy it.
This first line of defense is relatively short and lasts hours or days.
The second line of defense takes days to weeks to get going. This is the long-lasting adaptive immune response. It depends on the immune system’s T and B cells that learn to recognize specific invaders, such as a protein from the coronavirus. If the invader encounters again, months or even years in the future, it is immune cells that will recognize the old enemy and generate the antibodies that will take it down.
In the case of the SARS-CoV-2 vaccines, it takes about two weeks to develop the adaptive response that provides long-term protection against the virus.
When you get the vaccine, what you notice in the first day or two is part of the innate immune response: your body’s inflammatory response, which aims to quickly clear up the foreign molecules that cross your body’s perimeter.
It varies from person to person, but how dramatic the initial reaction is is not necessarily related to the long-term reaction. In the case of the two mRNA COVID-19 vaccines, more than 90% of the people vaccinated developed the protective adaptive immune response, while less than 50% had side effects, and most were mild.
You may never know how strongly your body’s adaptable immune response fits.
What are possible side effects?
Side effects are normal reactions to the injection of a foreign substance. It contains things like fever, muscle aches and discomfort at the injection site, and is mediated by the innate immune response.
Neutrophils or macrophages in your body notice the vaccine molecules and produce cytokines – molecular signals that cause fever, chills, fatigue and muscle aches. Doctors expect this cytokine reaction to occur when a foreign substance is injected into the body.
In studies where recipients or researchers did not know which individuals were receiving the mRNA vaccine or a placebo, approximately half of the people aged 16 to 55 who received a SARS-CoV-2 vaccine developed headaches after the second dose. This reaction may be related to the vaccine – but a quarter of people who only received a placebo also had a headache. In the case of very common symptoms, it can therefore be difficult to assign it to the vaccine with any certainty.
Researchers expect some reports of side effects. Adverse events, on the other hand, are things that doctors do not expect because of the vaccine. This would include organ failure or severe damage to any body part.
The blood clots that caused the U.S. to interrupt the distribution of the Johnson & Johnson vaccine are a very rare occurrence, apparently occurring at a one-to-one-million frequency. Whether it is definitely caused by the vaccine is still being investigated – but if scientists conclude, blood clots are an extremely rare side effect.
Which component in the survey causes side effects?
The only ‘active ingredient’ in the Pfizer and Moderna vaccines is the mRNA instructions that tell the recipient’s cells to build a viral protein. But the shots contain other components that help move the mRNA inside your body.
To get the vaccine’s mRNA into the vaccinated person’s cells where it can do its job, it must escape enzymes in the body that will naturally destroy it. Researchers protected the mRNA in the vaccine by wrapping it in a bubble of lipids that help prevent destruction. Other ingredients in the shots – such as polyethylene glycol, which are part of this lipid shell – can cause allergic reactions.
If I feel sick after my lap, does that indicate strong immunity?
Scientists have not identified any link between the initial inflammatory response and the long-term response leading to protection. There is no scientific evidence that anyone with the clearer side effects of the vaccine is better protected against COVID-19. And there is no reason why an exaggerated innate reaction will make your adaptive reaction better.
Both of the authorized mRNA vaccines provide protective immunity to more than 90% of the recipients, but less than 50% reported any response to the vaccine and far fewer had severe reactions.
Ultimately, you cannot determine how well the vaccine works inside your body, based on what you can detect from the outside. Different people do get stronger or weaker immune responses to a vaccine, but side effects that occur after the survey will not tell you what you are. This is the second, adaptable immune response that helps your body gain vaccine immunity, not the inflammatory response that those early pains cause.
This article was published from The Conversation under a Creative Commons license. Read the original article.