In plain English
Infectious disease is an internal medicine fellowship. Much of the work is consultative - advising on diagnosis and antimicrobial treatment for patients admitted under another service - alongside clinics for long-term infections and, at some centres, travel and transplant medicine.
Two institutional roles usually sit with this specialty: antimicrobial stewardship and infection prevention. That makes infectious disease physicians decision-makers on formulary, diagnostics and testing policy out of all proportion to their numbers.
It is one of the smallest adult medical sub-specialties, and it concentrates in hospitals and academic centres rather than in independent practice.
Training and credentials
An internal medicine residency, a fellowship in infectious disease of two years or more, then board certification.
Where they practise
Hospital consult services, academic medical centres, HIV and travel clinics, public health roles.
Infectious disease physicians on the public record
Counted from what providers file about themselves, with suppression applied before anything is counted, refreshed 2026-10-05. Names, specialties and practice locations are public; work email and phone are for signed-in customers.
| State | On record | With work email | With practice phone |
|---|---|---|---|
| California | 1,355 | 1,040 77% | 1,355 |
| New York | 1,116 | 914 82% | 1,116 |
| Florida | 1,114 | 694 62% | 1,114 |
| Texas | 930 | 643 69% | 930 |
| Pennsylvania | 662 | 522 79% | 662 |
| Illinois | 528 | 436 83% | 528 |
| Massachusetts | 505 | 451 89% | 505 |
| New Jersey | 502 | 349 70% | 502 |
Closely related, and where to find them.
Closely related
- Internal medicine physician Adult general medicine, and the classification most sub-specialties are filed beneath.
- Pulmonologist Lung medicine, usually combined with critical care - so usually a hospital specialty.
- Pathologist Diagnosis from tissue and from the laboratory - a small population with large budgets.
Find them
- Infectious disease physicians list counts by state, the fields a record carries, a sample record.
- Physicians physician data by specialty, state and employer.
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