24 June, 2024


“Covid Arm”

By Ranjula Ranasinghe

Ranjula Ranasinghe

My favourite uncle got his Covid vaccine, and he kept going on about his arm pain for over a month. Then my mum got her dose, and she also suffered for more than three weeks with pain, then my Aunt got her dose, and for her, there was no noticeable pain; instead, she just had a slight fever and a headache.

Why is this? Some people get unusual pains after being vaccinated, and some people don’t? Let’s chat about this, shall we?   

Pfizer BioNTech, Moderna and AstraZeneca COVID-19 mRNA vaccines cause common symptoms such as soreness and swelling.

The term “Covid Arm” is referred to the later reactions at the site of the injection following the soreness, such as itchinessrashesswellingwhen touched your skin feels relatively warmpain, spreading of the rash to your fingers/hands and rigid lump under your skin, where the jab took place.

These side effects are most common with the Moderna vaccine. Thankfully though, it seems that the Johnson and Johnson vaccine has no trace of these symptoms at all.

All this may sound very uncomfortable, but in reality, the “Covid Arm” isn’t even a bad thing; it’s actually a good thing. Your immune system is just doing its job like it’s supposed to (more on that later). Also, keep in mind that millions of people worldwide are being vaccinated, so even minor vaccine side effects would gain a lot of attention since a lot is at stake.

What is the reason for this?

To understand this, I will give you a very basic summary of how mRNA vaccines work since they are an unconventional, new type of technology used and, therefore, essential to understand.  

See, the COVID-19 virus works by infecting you with their nasty spikes. These spikes have the ability to attach themselves to specific cells in your body and then infect those cells. Yikes!

Therefore, with the mRNA vaccine, we are essentially training our immune system to recognise these spikes by having our own bodies produce them. So how did scientists make this possible?

They took the virus’s RNA (basically its blueprint) and then isolated the instruction in that RNA for producing spikes, and with this, they created mRNA, messenger RNA. So now, this unique form of RNA is able to now enter your cells and give those instructions to solely build the spikes of the coronavirus. How cool is that, huh?

So we are basically giving our cells a recipe to mass create these spike proteins.

While this process is taking place, now is when the immune systems kicks in and joins the action. Your immune cells all gather around at the site of the injection, and they start learning to recognise and fight off the protein spikes so that if you do get ill with the same virus/spike, your body will remember the earlier spike and know how to deal with it then and there.

And this identification process is what causes the pain and swelling of your arm; it’s the inflammation of the White Blood cells (the cells of your immune system) crowding up around your arm to investigate the foreign proteins. Inflammation is a fundamental reaction and is natural and harmless (It’s like a stranger knocking at your door, you and everyone in your family is curious to know who it is).

How much does a “jab” usually hurt?

Well, that depends on several factors such as: Where on the body you get jabbed, the composition of the vaccine, and how you feel about needles (you may have psychological effects towards it).

Intramuscular jabs are crucial. These are injections that are deep into the muscle and not just given under the skin. According to medical sciences, this is because each tissue has the capacity to absorb the injected fluid. Otherwise, if you inject the fluid into a fatty skin area, it is unable to go anywhere and will get trapped, leading to immense pain. So hopefully, everyone reading this got jabbed on either their left or right shoulder.

Not to mention, muscles are also full of blood vessels and are competent in cleaning out the fluid rapidly, hence causing less pain, swelling and itchiness. Plus, muscles also have a greater variety of immune cells, so intramuscular shots are definitely more effective!

So that is to do with the location of the jab, now moving onto the composition of the vaccine:

Obviously, there are a vast array of ingredients used in making the vaccine, but the one ingredient that stands out and is significant in contributing to the arm pain are “adjuvants”. 

Adjuvants are used in the Moderna, AstraZenecaPfizer BioNTech COVID-19 vaccines. They are substances added to vaccines to help and make it easier for our immune system to identify a foreign invader.

They are made of materials such as Aluminium or small parts of bacteria.

They aren’t harmful to us, but they do increase the rate and volume of inflammation since such substances aren’t normally found in our bodies, which means that more immune cells will be intrigued and attracted to the scene of the injection to find out what’s there and start processing the new information.

But in summary, even though these adjuvants increase your pain, they are still much needed; they help us have stronger and long-lasting protection against the virus. And that is what we want, so please don’t worry.

The Covid Arm doesn’t usually last very long, only around 3 to 5 days. The symptoms will then automatically wear off on their own. However, if you do experience excruciating pain and/or if it’s long-lasting, you shouldn’t hesitate to consult your doctor about it.

Are there any Solutions? Yes, but unfortunately, these solutions may only reduce the pain and not remove it completely.

* Cold compressions – this is known as cryotherapy. The vessels that supply blood to these muscles constricts/narrows as a response to cold temperatures. (This reaction is called vasoconstriction, it decreases the blood flow to the muscles, which helps to reduce the thermal energy lost from the warm blood). Meaning that there would be less inflammation/swelling in that particular area, as again, there is less blood rush into that particular area. 

This will obviously reduce the pain, but it also slows down the immune cells duty, since more blood to an area would result in more inflammation and pain to that area since the immune cells are really getting to work with their new information (the spikes). But by using cold compressions, we are just hindering/delaying the process for our immune cells. This isn’t too bad, but it is up to you if you want to use cold compressions. 

* Topical anti-inflammatories – The word “Topical”, means pertaining to a particular surface area, for example, applying the substance to a certain area of the skin, and it is only meant to work on that specific area of the skin, in this case, your shoulder. These substances are present as gels, sprays, foams and creams. They contain compounds that reduce inflammation, such as ibuprofendiclofenacfelbinacketoprofen, or piroxicam

* Oral Antihistamines – For example, Diphenhydramine can be used to help with the itchiness symptom of the Covid Arm and other allergies as well. It is used by injections into a vein/muscle, can be used by mouth, or applied on to the skin.

* Plenty of rest – Try your best to preserve your energy during this period; your immune system needs it more!

*Ranjula Ranasinghe – St. Anselm’s College, Wirral






https://www.popsci.com/why-does-my-arm-hurt-day-after-i-get-my-flu-shot/#page-2 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1118997/












https://academic.oup.com/jpids/article/4/4/396/2580461 https://www.cdc.gov/vaccinesafety/concerns/adjuvants.html

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Latest comments

  • 3

    Yes the ‘covid arm’ is very common and i know people who took the jab and experienced it.
    But many have also become permanently paralysed or died from taking the jab.
    Interesting how you conveniently failed to mention the latter 2.

  • 11

    A very useful write-up that has all the hallmarks of compassion and patient well-being. These are essential criteria for medical staff. Unfortunately, many highly sought-after private practitioners do not allocate enough time for care and merely go through the motions of diagnosis and prescription. If you are either a medical student or already in practice, I am confident you will do well. Best wishes..!

  • 3

    Thanks Rannual for the write-up on the Covid vaccines.

    I was wondering about mRNA. As our DNA is not involved in sending us messages to fight this virus, we are not evolving as humans to fight these viruses. We will have to perpetually use mRNA to fight disease. The traditional vaccines on the other hand, use actual bits of virus, and our whole DNA is gradually programmed to fight viruses. Probably after 500 years, the flu virus will have no effect on us. I believe that Astrazeneca and Johnson and Johnson vaccines are more of the traditional vaccines, though J&J causes blood-clots. Not sure how the Sinopharm vaccine works.

    Tylenol/Panadol don’t interfere with the essential inflammatory response, and will help with the pain.

    • 1

      Sorry, I mean, Ranjula. My phone changed the name.

    • 0

      The great mrs dum dud struck again , The only advantage of the Mrna vaccines is that they are produced without an actual virus(so synthetically ) and therefore they can be easily mass produced(in theory). the Sputnik and the AZ use a different virus that carries Covid19 DNA while the Sinopharm Sinovac use dead coronaviruses.

      They are essentially doing the same thing. Getting the body disease-fighting mechanisms to identify the threat .

      The efficacy numbers in my opinion are garbage as the virus is mutating differently is different areas in the world and unless they are compared against the same variant to variant group., the numbers are just a pissing contest between different companies.

      • 0

        “They are essentially doing the same thing”– but not exactly the same thing.
        There is debate that is still going on about what the difference means in terms of short and long term effects, especially about the mRNA vaccine.
        We cannot be flippantly dismissive.

  • 3

    The young author has quite the knack for peeking interest and breaking it down for layman’s comprehension!

    To reduce pain and discomfort where you got the shot, the U.S. CDC also recommends that you “Use or exercise your arm”. I found frequent simple stretching to be very effective.

    As part of the inflammatory process at the site of injection, in addition to the migration of white blood cells out of the micro blood vessels into the affected area, there’s also leakage of fluids due to increased permeability of the micro vessel walls in the area, and hence the swelling.

    Muscle movement essentially assists in draining off fluids from the area of swelling into the lymphatics. Simple and frequent stretching of the injected arm will do.

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