Ever Wonder Why You Get The COVID Vaccine Shot In The Arm?

By Shantanu Sodhi +2 more

By now many of us have received at least the first dose of any of the approved COVID-19 vaccines. Everyone knows that the COVID-19 vaccines are administered to the upper arms. But have you ever wondered why?

Most vaccines such as those for Hepatitis B, DPT, HPV, are injected into the upper arms, except some like the Rotavirus vaccine or Oral Polio vaccine which is administered orally. But why the arm? Read on to find the answer.

How does the vaccine work?

Once the vaccine is administered into the upper arm muscle, it is taken to the nearest lymph nodes. There the vaccine comes in contact with the guardians of the body – the White Blood Cells which function to develop immunity against the vaccine. Your body starts producing antibodies and your immunity is now active and you have a defence mechanism against Coronavirus.

What is so special about the upper arm?

There is a muscle in your upper arm called the deltoid muscle. It is a triangular muscle extending from the shoulder to the upper arm and it helps you lift your arm. COVID-19 vaccines are administered right into the deltoid muscle through the intramuscular route. The deltoid muscles have excellent blood circulation. This leads to quick absorption of the components of the vaccine, maximization of the immune response and at the same time reduces the possibility of severe after-effects of the vaccine. 

On top of that, the deltoid muscle injection is easy and fast, which means many doses of the vaccines( to multiple people) can be administered in a short time. This factor is crucial when we are racing against the clock to get the entire population vaccinated by the year-end. 

You will also experience less pain at the vaccine administration site.  

If a person has lost both hands, where can he/she take the jab?

If it is not possible for a person to take the COVID vaccine in arms due to any reason like missing or amputated arms, he/she can be given the intramuscular shot of COVID vaccine in the thigh region which is also a suitable site for intramuscular injections.

Localized reaction

There is no escape from the side effects of COVID-19 vaccines but the side-effects indicate that the vaccine is working. Did you know that one of the most important reasons why COVID-19 vaccines are administered to the upper arm muscle is that the side effects don’t spill over to the nearby muscles and tissues? There will only be localized pain, irritation and inflammation.  

Since the deltoid upper arm muscle has a good blood supply, recovery is rapid.

How to deal with vaccination pain?

Do not rub the vaccine administration site. Once you come home, you can gently apply a cold compress to the area to dull the pain. Paracetamol can help alleviate pain and discomfort. It is normal for the pain to last at least a week and there may even be some bruising at the site. If pain intensifies suddenly or you notice any other unusual side-effect, contact your doctor.  


Vaccination is the only way we can develop herd immunity. COVID-19 vaccines are safe and please do not believe any of the rumours being circulated online. Book yourself and your loved ones a slot. At the same time, continue to maintain COVID safety protocol such as wearing masks and sanitising hands. It doesn’t take much to keep yourself safe.

Disclaimer: The information included at this site is for educational purposes only and is not intended to be a substitute for medical treatment by a healthcare professional. Because of unique individual needs, the reader should consult their physician to determine the appropriateness of the information for the reader’s situation.

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