Communicable & Infectious Disease


Preventing and controlling the spread of disease is at the heart of much public health work. From influenza and Lyme disease to malaria and Ebola, outbreaks of infectious diseases can have an extraordinary impact on human health [1]. Viral hepatitis, influenza, and tuberculosis (TB) remain among the leading causes of illness and death in the United States and account for substantial spending on the related consequences of infection [2]. DC Health relies on various partners, including healthcare facility staff, school nurses, and laboratory staff to provide us with information about diseases that can spread in the District or are of public health concern. We use this information to monitor the health of District residents, identify and investigate potential outbreaks, evaluate the effectiveness of public health interventions, and contribute to the national surveillance data collected by the Centers for Disease Control and Prevention (CDC).

The DC Healthy People 2020 goals related to Infectious Diseases include:

     1. Vaccine-preventable infections are rare and infectious diseases are properly contained.
     2. Food safety and hygiene are improved to reduce and limit the spread of
food-borne-related illnesses. 

Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; the diseases can be spread, directly or indirectly, from one person to another [3]. Some are spread through the air, by touch or through bodily fluids. Some diseases produce mild symptoms and others can be lethal. 

Zoonotic diseases (or zoonoses) are infections that can be spread between animals and people. This includes diseases carried by ticks and mosquitoes. They are caused by many different things, ranging from diseases caused by microscopic bacteria and viruses to large parasites such as worms and fleas. Some zoonotic diseases make both animals and people sick, while some do not make animals sick but can make people sick [4].

There are many ways to prevent the spread of disease. Vaccinations have helped eliminate or greatly reduced many disease threats. Proper hand washing, especially before and after handling food and using the toilet, can also help keep germs at bay. Other important ways to slow or stop disease transmission are by ensuring the food we eat and water we drink is safe, avoiding close contact with people who are sick, and practicing safe sex [1].

Coronavirus (COVID-19)

Coronavirus disease 2019 (COVID-19) is a respiratory illness that can spread from person to person. The virus that causes COVID-19 is a novel coronavirus that is thought to spread mainly between people who are in close contact with one another through respiratory droplets produced when an infected person coughs or sneezes. It also may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or their eyes [5]. 

How to Protect Yourself 

• Get Vaccinated

• Wash hands with soap and water for at least 20 seconds multiple times a day. An alcohol-based hand sanitizer can be used if soap and water are not available

• Avoid touching eyes, nose and mouth with unwashed hands

• Avoid close contact with people who are sick

• Stay home when feeling sick

• Cover your cough or sneeze with a tissue, then throw the tissue in the trash

• Clean and disinfect frequently touched objects and surfaces

Symptoms & Treatment

The symptoms that are currently being seen with COVID-19 are cough, fever, headache, new loss of taste or smell, repeated shaking with chills, sore throat, shortness of breath, and muscle pain. Stay home and self-quarantine until you are free of fever, signs of a fever, and any other symptoms for at least 24 hours and without the use of fever-reducing or other symptom-altering medications. Seek medical attention if you have reason to believe you have been exposed to coronavirus or influenza. Call your healthcare provider before visiting a healthcare facility. 

Vulnerable Communities

Based on currently available information and clinical expertise, older adults and people of any age who have serious underlying medical conditions might be at higher risk for severe illness from COVID-19 [6]. Based on what we know now, those at high-risk for severe illness from COVID-19 include:

• People aged 65 years and older

• People who live in a nursing home or long-term care facility

• People of all ages with underlying medical conditions including asthma, diabetes, chronic lung disease, liver disease, and heart conditions.

• People who are immunocompromised

• People experiencing homelessness

• Pregnant people

Recovery & Response

The District of Columbia is closely monitoring key public health signs to determine when and how to reopen the District in a way that is safe, measured, data-driven, and sustainable. The timing of when it is safe to relax certain social (physical) distancing policies will be determined in part by the following four criteria: 1) Level of Community Spread, 2) Health System Capacity, 3) Public Health System Capacity, and 4) Community Engagement. Each metric measures key factors related to the extent of COVID-19 transmission in our city and our collective capacity to contain the spread of the virus. Once we reach the thresholds for a sustained period of time, the District may move into new phases to gradually lift restrictions. 

It will take all of us to work together to help slow the spread of COVID-19. The District created an online hub to identify food resources, health guidance, resources for businesses and individuals, operating status of DC Government, and more.


As of Saturday, May 1, 2021 the District transitioned to the use of 11 high-capacity, walk-up, no appointment needed vaccination sites. Walk-up sites are for first doses. When you receive your first dose, you will still make an appointment to get your second dose. The walk-up sites operate in addition to the pharmacies, clinics, and health care providers that are also administering the vaccines citywide. For District residents who can't leave home, please call 1-855-363-0333 and the District will send someone directly to you. 


Given the global nature of disease transmission and the District’s location in a thriving metropolitan area with extensive commuting norms and tourism, the threat for catastrophic infectious disease epidemics remains high. DC Health relies on various partners, including healthcare facility staff, school nurses, and laboratory staff to report information about diseases that can spread in the community or are of public health concern.

DC Health uses this information to monitor the health of District residents, identify and investigate potential outbreaks, evaluate the effectiveness of public health interventions, and contribute to the national surveillance data collected by the Centers for Disease Control and Prevention (CDC). 

For example, flu surveillance activities are conducted over 33 weeks from Fall to Spring, following the CDC guidelines. With a record high flu season in 2017-2018, the peaks in the several years before and season after have been more modest. DC Health also monitors emerging infectious disease situations closely and ensures the DC healthcare community has the most updated guidance by providing information via Health Notices and sharing how providers can reach the DC Health epidemiology team if there is a concern. 


Immunization has played a vital role in increasing life expectancy in the 20th century, largely due to improving child survival through reduction in infectious disease mortality and disability. Vaccines are among the most cost-effective clinical preventive services and childhood immunization programs provide a very high return on investment. For example, for each birth cohort vaccinated with the routine immunization schedule, society [2]:

• Saves 33,000 lives.

• Prevents 14 million cases of disease.

• Reduces direct health care costs by $9.9 billion.

• Saves $33.4 billion in indirect costs.

Current vaccination efforts in the U.S. targets 17 vaccine preventable diseases across the lifespan. Even with such advances in vaccines, the effectiveness depends on vaccinating a large majority of the population being protected (herd immunity). Without widespread immunization, the entire community is at risk for outbreaks that have not been seen in generations. People in the United States continue to get diseases that are vaccine preventable. Infectious diseases that are not yet eradicated remain a major cause of illness, disability, and death. The minor risks of vaccines are dwarfed by the substantial effects of infections such as measles, which cause death or permanent disability in up to 10% of those who contract it [2].

Vaccination rates in school children in the District have been declining over time, down to 79.1% in 2017. Campaigns like “No Shots No School” and updates in local legislation have attempted to halt this decline in coverage rates. Similarly, while higher than the national rate of 70%, 74% of toddlers (19-35 months old) in the District have received all the recommended vaccinations, falling short of herd immunity levels. For further information on flu and HPV vaccines in the District, there's additional data on the Safety Behaviors page to explore.

For a snapshot on compliance rates for schools within the District related to Measles, Mumps and Rubella vaccinations, see the following dashboard:


1. American Public Health Association. Communicable Disease. 2019.

2. Healthy People 2020. Immunization and Infectious Diseases. 2019

3. World Health Organization. Infectious Diseases. 2018

4. DC Department of Health. Zoonotic Diseases.

5. CDC. What You Need to Know About COVID-19. 2020

6. CDC. Coronavirus Disease 2019 People Who Are At High Risk. 2020.

Additional Data Resources

• DC Influenza Surveillance and Reporting-MMWR Weekly

• Coronavirus Outbreak Surveillance Data

Photo Credits:

"Study Participant Receives NIAID/GSK Candidate Ebola Vaccine," NIH-NIAID, CC BY-NC 2.0

Courtesy of The Yards Park DC