A notifiable disease is any disease that, when diagnosed, must be reported by healthcare providers or laboratories to public health authorities. These diseases earn their spot on the list because of their contagiousness, severity, or frequency. The reporting requirement exists so public health agencies can detect outbreaks early, track how diseases spread, and coordinate responses before a localized problem becomes a widespread one.
Why Certain Diseases Require Reporting
Not every illness triggers a mandatory report. The diseases that do share at least one of three characteristics: they spread easily between people, they cause serious harm, or they occur frequently enough to signal a public health trend. Measles, for example, checks all three boxes. A single case in a community can spark a rapid outbreak, so health departments need to know about it immediately. Tuberculosis, rabies, plague, and anthrax are on the list for similar reasons, though each carries different levels of urgency.
The list also includes sexually transmitted infections like chlamydia, gonorrhea, and syphilis, which may not make headlines but occur at high enough rates that tracking them helps public health agencies allocate testing resources and identify clusters. Foodborne illnesses like salmonellosis and campylobacteriosis are reportable because a spike in cases can point to a contaminated food source that needs to be pulled from shelves. COVID-19 was added in 2020 and remains a nationally notifiable condition.
What’s on the List
The CDC maintains a national list of notifiable conditions that spans dozens of diseases. Some of the most recognizable include:
- Vaccine-preventable diseases: measles, mumps, pertussis (whooping cough), chickenpox, diphtheria, rubella, tetanus
- Foodborne and waterborne illnesses: cholera, salmonellosis, shigellosis, giardiasis, cryptosporidiosis
- Sexually transmitted infections: chlamydia, gonorrhea, syphilis
- Vector-borne and zoonotic diseases: Lyme disease, malaria, Zika virus, rabies, plague
- Other serious conditions: tuberculosis, anthrax, botulism, hepatitis A
Each state can also add diseases to its own list based on local concerns, so the reporting requirements you encounter may vary depending on where you live. A disease that’s notifiable in one state isn’t necessarily notifiable in another, though the nationally notifiable conditions apply across all U.S. jurisdictions.
How Reporting Works
The reporting chain starts at the point of diagnosis. When a healthcare provider identifies a notifiable disease, or when a laboratory confirms a positive test result, that information gets sent to the local or state health department. This happens through a combination of methods: automated electronic systems that pull data directly from electronic health records, electronic laboratory reporting that transmits results from labs to health departments in real time, and in some cases, phone calls or paper forms.
State and local health departments then forward relevant data to the CDC’s National Notifiable Diseases Surveillance System (NNDSS), which aggregates case information from across the country. This national-level picture is what allows the CDC to spot trends that no single state could see on its own, like a foodborne outbreak linked to a product distributed in multiple regions.
Laboratories carry specific responsibilities beyond just sending results. In Georgia, for instance, state rules require clinical labs to retain reports of notifiable diseases for two years and to hold onto clinical samples containing a disease agent for at least one week. If the state health department requests additional materials for further testing, labs are required to provide them.
Privacy Protections During Reporting
Mandatory disease reporting might sound like it conflicts with medical privacy, but federal law specifically carves out an exception for it. Under HIPAA’s Privacy Rule, healthcare providers and laboratories are permitted to share protected health information with public health authorities without patient authorization when the purpose is preventing or controlling disease. This covers not just disease reporting but also vital events like births and deaths, public health investigations, and surveillance activities.
There are limits. Providers are generally required to share only the minimum amount of information needed to accomplish the public health purpose. They can rely on the public health authority’s own determination of what information is necessary when responding to a specific request.
What Happens After a Report Is Filed
The point of collecting all this data isn’t just recordkeeping. When a health department receives a report of a notifiable disease, it can trigger several practical responses depending on the disease and circumstances. For highly contagious infections like measles, the immediate priority is contact tracing: identifying everyone the infected person may have exposed and getting them tested, vaccinated, or monitored. For foodborne illnesses, investigators work backward to identify the contaminated source.
At a broader level, surveillance data shapes vaccination campaigns, funding decisions, and public health policy. A sustained rise in pertussis cases in a particular county, for example, might prompt targeted outreach about booster shots. Tracking gonorrhea cases nationally helps identify emerging patterns of antibiotic resistance. The data also helps researchers understand seasonal patterns, geographic hotspots, and long-term trends in disease burden.
International Reporting Requirements
Disease surveillance doesn’t stop at national borders. The International Health Regulations (IHR), a legally binding agreement covering 196 countries, require nations to notify the World Health Organization about public health events that could have international implications. This includes disease outbreaks but also extends to any health risk, regardless of its origin, that could spread across borders.
Each country designates a National IHR Focal Point responsible for communicating with the WHO. The IHR also require countries to maintain the capacity to detect, assess, and report acute public health risks. This framework is what enabled the global response to events like the Ebola outbreaks in West Africa and the early spread of COVID-19, though the speed and transparency of reporting has varied widely between countries in practice.