Bacterial & Viral Infections: What's the Difference?

Updated July 2020

[This article was written with Dr. Mia Finkelston, Medical Director and family physician on Amwell]

You’re sick. You’re not entirely sure what it is, but you know you want it to go away. To get back to good health, it is essential to understand what caused the illness and the underlying infection. There are two major types of infections: bacterial and viral. But what is the difference and how are they treated? Let’s start with the easy part – bacterial infections are caused by bacteria and viral infections are caused by viruses.

Viruses and bacteria are tiny organisms, otherwise known as microorganisms. Both types of infections flourish in living things – like plants, animals, and people. If bacteria gets into your body, they divide and spread, causing an infection. Viruses behave very differently from bacteria – they latch onto your healthy cells and reprogram them to make more of the virus instead.

Dr. Mia Finkelston is a family physician with Amwell who emphasizes patient education during her virtual visits. With a concern for humans becoming antibiotic-resistant, she underscores the difference between the two types of infections, and when antibiotics are appropriate for treatment.

Perhaps the most important distinction is that antibiotic drugs usually kill bacteria, while viruses do not respond to them. Antibiotics are amazing drugs that can kill bacteria rather quickly. We don’t have that same option for many viruses, particularly for those that cause the common cold, upper respiratory infection or simple head congestion and cough, which I see every day online.

So, how does one become antibiotic-resistant and what does that mean for future treatment? Inappropriate use of antibiotics can create strains of bacterial disease that then become resistant to certain antibiotics. When antibiotics are used incorrectly, there is a risk of not having a way to treat illness in the future.

There are many conditions that are caused by bacteria or viruses. Conditions that can be treated online and that may be bacterial or viral include, but are not limited to:

• Pink eye
• Bronchitis
• Some ear infections (swimmers ear, etc.)
• Diarrhea

Each condition has a unique treatment plan based on type of infection. There are many bacterial conditions we treat online that can be treated with antibiotics (note: prescribing is at the doctor’s discretion and antibiotics are not always necessary for treatment). Understanding the difference between the two types of infections can help with diagnosis, treatment and prevention of antibiotic resistance. So, next time you’re sick, let the knowledgeable doctors at Amwell help you figure out whether it’s bacterial or viral and get a customized treatment plan, just for you.