Is a Virus a Living Thing? The Life Cycle of a Virus

It only takes a quick glance down the grocery store cleaning aisle to find shelf after shelf of sprays, wipes, and soaps that promise to kill household germs. Yet, none stop to ask the question: are viruses even alive in the first place?

Viruses are microscopic bits of genetic information (DNA or RNA) surrounded by a protective coating called a capsid. They can infect humans and other living things, multiplying quickly once they find a host. But they can’t really do anything on their own. Viruses toe the line between chemistry and biology, and scientists still can’t agree on whether they can be called living creatures. 

Here, we’ll dig into whether viruses are alive, what the virus life cycle looks like, and how you can protect yourself from infection.

Are viruses alive?

There’s no simple answer to the question of whether viruses are alive or not. Scientists use a few basic criteria to decide if something is living or nonliving, but viruses don’t fit neatly into either category. It’s a big ask to describe exactly what makes something alive, but most definitions agree that living things:

When a virus infects a host cell, it can replicate, use energy, and adapt to its environment. But it can’t do any of that on its own. Many viruses even have trouble surviving outside of a host cell. While this kind of “borrowed life” doesn’t check off all the boxes of being a living creature, it’s still close enough to inspire an ongoing debate about the true nature of viruses. 

Fortunately, deciding whether viruses are alive isn’t nearly as important for public health as understanding how they work.

How Viruses Work: The Life Cycle of a Virus

Since viruses can’t do anything without help, their life cycle doesn’t start until they begin invading a host cell. This six-step journey follows a virus as it takes over a cell and uses its machinery to create more viral particles. 

1. Attachment

Attachment is the first contact between a virus and a host cell. In this step, proteins on the virus’s outer shell act as keys, fitting into specific receptors on the cell’s surface. This binds the virus to the host cell and “unlocks” the cell so the virus can enter.

2. Entry

Once the virus is bound to the host cell, it starts to make its way inside. Most viruses enter cells through a process called endocytosis, which is when the cell membrane (outer layer) wraps around the virus and brings it into the cell. 

3. Uncoating

Inside the cell, all or part of the virus’s outer shell is removed, freeing the genetic material inside.

4. Replication

Now that the virus’s DNA or RNA is free, it can use the host cell’s machinery to create copies of its genetic information and proteins—everything it needs to make new viruses.

5. Assembly and maturation

Then, the virus’s genetic material is packaged together and surrounded by a new protein shell, creating a complete infectious virus particle called a virion. 

6. Release

Lastly, the new viral particles are released into the body, where they can bond to new host cells and start their life cycle anew. 

How does your body fight viruses?

Once a virus enters the body—typically through the mouth or nose—it starts hijacking cells and using them to multiply as quickly as possible. Cells infected by a virus may be changed, damaged, or killed, which can cause some symptoms of a viral infection. Other symptoms may be unintended side effects of the immune system’s efforts to fight off the infection.

When a virus enters your body, it triggers an immune reaction. Your white blood cells are always on the hunt for foreign invaders (called antigens) that don’t belong in your body. When they detect a virus, they respond immediately. White blood cells, antibodies, and other parts of your immune system work together to attack and destroy the threat. This attack may also involve:

• Raised body temperature or fever (heat can inactivate many viruses);
• Release of a chemical called interferon that blocks viruses from reproducing;
• Inflammation and redness caused by increased blood flow as your body sends immune cells to fight the infection.

If your body recognizes the virus from a vaccine or previous infection, certain white blood cells (called lymphocytes) join in the attack, helping your body destroy the virus as quickly as possible. Depending on how fast your immune system fights off the virus, you may notice mild symptoms or no symptoms at all. 

Most of the time, your immune system is your body’s only line of defense to keep a virus from spreading. Antibiotics can’t kill viruses or help with symptoms of a viral infection. Antiviral medications may help, but they’re only available for a handful of specific viruses. So, treatment usually means doing what you can to manage your symptoms while you wait for your immune system to take care of the infection.

Tips for Stopping a Virus in Its Tracks

So, if viruses are only kind of alive, can they really be killed? Absolutely. (Technically, this is called “inactivating” the virus.) Your immune system is in charge of killing off any viruses that enter your body, but there’s plenty you can do to help keep yourself from getting sick in the first place. 

Vaccination—Vaccines help teach your immune system to recognize and fight a specific virus, such as the flu or COVID-19. Your healthcare provider can help you stay up-to-date on recommended vaccines.

Handwashing—Washing your hands with soap and water can help kill virus particles by breaking them apart. Then, the soap traps dirt, viruses, and bacteria and lifts them off your skin so they’re washed down the drain when you rinse your hands. Hand sanitizer is a good backup when you’re not near a sink, but it’s not as effective as soap and water.

Disinfecting—Disinfectants can help kill viruses living on surfaces, such as doorknobs, counters, light switches, and faucets. Look for cleaners that contain bleach, hydrogen peroxide, or isopropyl alcohol, all of which contain chemicals that can inactivate virus particles. Use cleaners according to the manufacturer’s instructions, and never mix different cleaners.

And in the spirit of avoiding viral infections, you can also take these steps to help lower your exposure to airborne viruses.

Wearing a mask—Masking up may help reduce your risk of catching a virus, especially when:

• You’re traveling or visiting crowded indoor spaces;
• You’re likely to be around someone who’s sick;
• There’s a flu or other viral outbreak in your area.

Ventilation—Improving ventilation by opening doors or windows, turning on fans, or running your HVAC system can help increase airflow and keep virus particles from building up in your home.

Air purification—Air purifiers can continuously filter and clean viruses and other pollutants from the air in your home. Molekule air purifiers, like the Molekule Air Pro, use Photo Electrochemical Oxidation (PECO) technology to not only catch, but destroy airborne viruses, helping to reduce your exposure to viruses, bacteria and more.

Living or not, viruses have all the equipment they need to hijack healthy cells and use them to multiply and spread. While your immune system is trained to fight off infection, the best time to stop the virus life cycle is before it even starts. You can help prevent the spread by washing your hands, disinfecting high-touch surfaces, and taking advantage of tools like the Molekule Air Pro to help protect yourself from exposure.