How Your Immune System Reacts to the Common Cold

When you catch a cold, your immune system jumps into action. Its first job is to fight the infection. The tell-tale symptoms of the common cold, like a cough and stuffy nose, are not from the virus itself. Those symptoms actually happen because of the things that are happening in your body as it responds to the virus.

As you start feeling better, your immune system is still working. Its next job is to get your body ready to fight off the virus in the future. This job is harder than the first because many different viruses can cause colds. Your body might learn to fight off one, but there are still others that could make you sick.

This article will teach you about what happens in your body when you catch a cold. You will learn about how your immune system fights off cold-causing viruses and how it tries to prevent you from getting sick again.

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What Happens In Your Body When You Catch a Cold

Viruses that cause the common cold attach themselves to the cells inside your nose in your nasal passages and sinuses. After they get inside, the cells start to make copies of themselves. This is called replication.

It takes about two days for the cells to trigger your immune system to start fighting. They do this by releasing chemical messengers called cytokines. Your body responds to the cytokines in a few ways.

First, your blood vessels will get bigger (dilate) to allow infection-fighting white blood cells to get to where the virus is. When the vessels swell, it can make your nose and airway feel stuffy or achy.

The white blood cells also release chemicals to help fight off the virus. The chemicals can cause these spaces to get inflamed. Fluid can also collect in them, giving you a runny nose and cough.

Cold viruses do not damage cells the way that influenza viruses do. The symptoms you feel when you have a cold happen because your body is fighting so hard, not because the virus is hurting your cells. When your immune system fights harder than it needs to, it's called overreaction.


When you are exposed to a cold virus, your immune system starts working to fight it. You feel the effects of all the hard work going on in your body as the symptoms of a cold, like a stuffy nose and sore throat.

Fighting Off Future Colds

While they're fighting, your white blood cells will get used to the virus making you sick. This is called sensitization. Then, your body will start making proteins that attach to proteins on the virus and tell your white blood cells to destroy it. These are called antibodies.

Once you get over a cold, some antibodies against the virus stay in your body. If you get exposed to that virus again, your body will remember and make more antibodies to fight it off. In some cases, that quick response means you won't get sick again. If you do get sick, your cold might not last as long or be as bad as it was the first time.

Your body's response sounds like a good plan, but it's not as simple as it sounds. There are more than 200 different viruses that cause colds. Throughout your life, you probably won't get the same one twice. That's why most people get about two to three colds each year.

Most colds are caused by rhinoviruses. This type of virus can also cause sinus infections and ear infections, and even trigger asthma attacks.

Other viruses that cause colds include:

  • Respiratory syncytial virus (RSV): This virus is very contagious, but most people who are generally healthy do not get very sick from RSV. However, babies, older adults, and any person with a weak immune system can get seriously sick if they catch RSV.
  • Parainfluenza viruses: Even though the name sounds like it, these viruses are not the same as the ones that cause the flu.
  • Adenovirus: Many colds are caused by this type of virus. However, one type, adenovirus 14, causes severe illness. People who catch it may have a cold that turns into pneumonia.
  • Coronaviruses: Most people have become familiar with this type of virus because one of them, SARS-CoV-2, causes COVID-19. Another respiratory illness, Middle East respiratory syndrome (MERS), is also caused by a coronavirus. There are many other coronaviruses that commonly cause mild colds. Most people will catch at least one coronavirus in their life.
  • Metapneumovirus: This type of virus causes infections in the upper and lower respiratory tract. The symptoms are usually mild. The virus is most active in the winter and early spring.


When you get a cold, your body makes antibodies against the virus that caused it. If you're exposed to the virus again, the antibodies remind your body how to fight it.

While it is helpful for your body to make antibodies, there are more than 200 different viruses that cause colds. Even if your body learns to defend itself against a few of them, there are still many more that can make you sick.

Will There Ever Be Vaccine for Colds?

Vaccines work by exposing your immune system to proteins on viruses and bacteria. That means your body will start making antibodies without you having to get sick.

The flu, COVID-19, and RSV vaccines only work on viruses. You might wonder why we don't have vaccines for colds if they are also caused by viruses. Remember: There are more than 200 viruses that cause colds. We would have to make vaccines for every single one.


Even though we have vaccines against some viruses, like the flu and COVID-19, it would be much harder to make vaccines against colds. There are hundreds of viruses that cause colds, and we couldn't make a vaccine for every single one.


The common cold is caused by one of more than 200 different viruses. When your body is exposed to a cold-causing virus, it jumps into action to fight off the infection.

Cold viruses don't damage cells as other viruses do. However, there are a lot of changes taking place in your body as your immune system fights the infection. When you get a runny nose or a cough from a cold, these symptoms are actually signs that your immune system is working.

Even after you start feeling better, your immune system is still working. Your body makes proteins called antibodies against the virus that made you sick. If you get exposed to the virus again, your body will remember how to fight it off.

That said, there are hundreds of viruses that cause colds. Even if your body has learned how to protect you from one, there are plenty more that can still make you sick.

A Word From Verywell

When you catch a cold, your body will jump into action to defend against the virus. Your immune system also works hard to prepare your body to fight off the virus in the future, should you run into it again.

That said, fighting an infection is a lot of work. Some people get colds more often than other people because their immune systems aren't as strong. For example, taking some medications or having certain health conditions can make your immune system weaker.

There are some things that you can do to help keep your immune system in fighting shape. For example, eating a nutritious diet, getting regular exercise, managing your stress levels, and getting enough sleep.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Warner SM, Wiehler S, Michi AN, Proud D. Rhinovirus replication and innate immunity in highly differentiated human airway epithelial cellsRespir Res. 2019;20(1):150. doi:10.1186/s12931-019-1120-0

  3. MedlinePlus. Immune response.

  4. Centers for Disease Control and Prevention. Common Cold.

  5. Centers for Disease Control and Prevention. Common Colds: Protect Yourself and Others.

By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.