How to Become an Infectious Disease Physician

Skills, Education, and Practice

Doctor consulting senior woman in hospital bed

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An infectious disease physician is a doctor of internal medicine who completes additional training to specialize in infectious disease prevention and treatment. Most of these doctors work in hospitals and clinics to help people who have contracted common infectious diseases.

What Are Infectious Diseases?

Infectious diseases are illnesses caused by bacteria, viruses, fungi, or parasites. You may be exposed to these organisms in the environment, such as in water, or they can be transmitted by another person or an animal. One of the most common examples of infectious diseases is influenza (flu). Infectious diseases include sexually transmitted diseases (STD) such as HIV/AIDS. When they are transmitted from animals to humans, they are called zoonotic diseases.

While some infectious diseases become an epidemic, spreading throughout a population, many happen at a fairly constant rate, known as being endemic. Areas of increasing concern are with hospital-acquired infections and organisms that are resistant to antibiotics.

Becoming an Infectious Disease Physician

In order to become an infectious disease physician, you must first complete the process of becoming an internal medicine physician, or internist.

That requires a college bachelor's degree, followed by four years of medical school. This education is very heavy in science, especially biology and chemistry. After that, you will have a 3-year residency in internal medicine before being qualified to be board-certified in internal medicine.

An internist may then complete an additional fellowship training program (two to three years in length) in infectious disease and become board-certified in infectious disease. 

Some infectious disease physicians may also choose to sub-specialize even further, focusing on one particular disease or type of infectious diseases, such as HIV/AIDS.


According to the Medscape’s Physician Compensation Report 2019, infectious disease physicians earn $239,000, on average.

What an Infectious Disease Physician Does

Most infectious disease physicians work for hospitals or medical centers. Many see patients in a clinic or outpatient setting, while some work in research centers. Infectious disease specialists help to identify and manage patients who have been infected. They also assist in the tracking and reporting of the spread of infectious diseases by maintaining close contact with public health professionals from the CDC and other public health organizations.

An infectious disease specialist will often have patients referred to her by other doctors if the patients have an infection that is hard to diagnose or difficult to treat.

They use tests such as laboratory cultures, antibiotic sensitivity profiles, antibody assays, and genetic analysis to help in identifying the cause of the illness and what medications and procedures will be needed to treat it.

The infectious disease physician may then follow a referred patient throughout their course of illness. Those who specialize in HIV/AIDS care will often be an integral part of their patients' healthcare team.

All infectious disease physicians understand epidemiology, and a part of the job is investigating where infections have come from and how they spread. They may perform this function at a medical center to help prevent hospital-acquired infections and spot the spread of disease in the community. Or, they may be employed by a public health organization or the CDC and have epidemiology as a more prominent focus of their practice.