In this module, we will discuss COVID-19 cases and Surveillance. We will analyze how different parts of the country are seeing different levels of COVID-19 activity and outline the goals for COVID-19 national surveillance. We will also discuss predictive mathematical models that are being produced to forecast the future of COVID-19 epidemics in the US and worldwide.

What is Public Health?
Public health is “the science and art of preventing disease, prolonging life, and promoting health through the organized efforts and informed choices of society, organizations, public and private communities, and individuals.” — CEA Winslow

What is Public Health?

What is Epidemiology?
Epidemiology is the “study of distribution and determinants of health-related states among specified populations and the application of that study to the control of health problems.” — A Dictionary of Epidemiology

What is Epidemiology?

What is Public Health Surveillance?

Public health surveillance is the ongoing, systematic collection, analysis, and interpretation of health-related data essential to planning, implementation, and evaluation of public health practice.

What is Public Health Surveillance?

COVID-19 Cases:

Different parts of the country are seeing different levels of COVID-19 activity. For most recent COVID-19 cases and deaths reported by U.S. states, the District of Columbia, New York City, and other U.S.-affiliated jurisdictions, please visit the Center for Disease Control and Prevention (CDC), Cases, Data, and Surveillance.

Also, please visit COVID-19 Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins.

For New Cases of COVID-19 In World Countries to see how countries around the world are working to “flatten the curve” of the coronavirus pandemic, please visit Johns Hopkins site.  When a country has fewer new COVID-19 cases emerging today than it did on a previous day, that’s a sign that the country is flattening the curve.

COVID-19 Surveillance:

For surveillance of COVID-19 and its cause, SARS-COV-2, CDC is using multiple surveillance systems run in collaboration with state, local and academic partners to monitor COVID-19 disease in the United States. COVID-19 surveillance draws from a combination of data sources from existing influenza and viral respiratory disease surveillance systems, syndromic surveillance systems, case reporting systems, commercial lab reporting, ongoing research platforms employed for the coronavirus response, and new systems designed to answer specific questions. These systems, taken together, create an ongoing picture of SARS-COV-2 spread and its effects in the United States and provide data used to inform the U.S. national public health response to COVID-19.

What are the goals for COVID-19 national surveillance?

  • To monitor the spread and intensity of COVID-19 disease in the United States.
  • To understand disease severity and the spectrum of illness.
  • To understand risk factors for severe disease and transmission.
  • To monitor for changes in the virus that causes COVID-19.
  • To estimate disease burden.
  • To produce data for forecasting COVID-19 spread and impact.
  • How is COVID-19 data used?

COVID-19 data can be used to help public health professionals and health care providers monitor the spread of COVID-19 in the United States and support better understanding of U.S. illness, disease severity, and social disruptions associated with COVID-19. This data helps inform the U.S. national public health response to COVID-19.

Surveillance reports created by CDC on COVID-19?

The CDC has modified existing surveillance systems, many used to track influenza and other respiratory viruses annually, to track COVID-19. Nationally, the percentage of laboratory specimens testing positive for SARS-CoV-2 continued to increase. The CDC posted the first of what will be a weekly surveillance report called, “COVIDView.” The report, updated each Friday, will summarize and interpret key indicators, including information related to COVID-19 outpatient visits, emergency department visits, hospitalizations and deaths, as well as laboratory data.

COVID-19 surveillance data is also used to produce publications. Many of these reports can be found online through the CDC’s Morbidity and Mortality Weekly Report (MMWR) . COVID-19 data are also used to inform guidance documents.

Predictive Modeling:
Numerous predictive mathematical models are being produced to forecast the future of coronavirus disease 2019 (COVID-19) epidemics in the US and worldwide. These predictions have far-reaching consequences regarding how quickly and how strongly governments move to curb an epidemic.
Forecasts based on the use of statistical or mathematical models (subsequently referred to as “models”) aim to predict changes in national and state level cumulative reported COVID-19 deaths for the next four weeks. Forecasting teams predict numbers of deaths using different types of data (e.g., COVID-19 data, demographic data, mobility data), methods, and estimates for the impacts of interventions (e.g. social distancing, use of face coverings).

According to Dr. James Simon at Cleveland Clinic, this is the first time coronavirus, COVID-19, has infected human populations so we don’t have prior COVID-19 infection pandemics to base any data on, any modeling. Everybody that’s putting out models are really doing their best with the methodology they think will work and what we can glean from other pandemics we’ve had in the past. The method that the Cleveland Clinic is using is a standard S-I-R model, which stands for susceptible, infected, recovery, and it’s a pretty classic model to predict how an infection will flow through a population. The reason it’s important to dampen the curve is because we want to try to get that peak number of infections down to the point where our healthcare system can handle those patients all at once.

If you get such a strong surge that we overflow our healthcare system and the healthcare system can’t take care of those patients, then we run into problems. That is what everyone is preparing for right now. We are trying to determine how high that peak is going to be and how many patients we’re going to see in the hospital, at any one time. So, all these social distancing measures that are going on right now are so important, not necessarily only because we can reduce the number of people that would become infected, but because the healthcare system can stay functioning and take care of patients, when they need to come in and we have the space and the facilities to take care of them.

This is kind of like the hurricane trackers that you see during hurricane season when a hurricane forms off the coast. It’s still far away from the mainland, you’ll have different models. Some will show the hurricane going to the Gulf, some will show tracking up the East Coast, but as time goes by and they gather more information, oftentimes, the models will come closer together and agree and that’s exactly what’s going on here. We’re still early on in a very unprecedented pandemic, so you may see different models that are predicting different, differently what’s going to happen but each of those models is taking the information that we learn day-by-day and incorporating that back into the model to improve its forecasting.

Predictive Models:

For more information, check:
Predictive Mathematical Models of the COVID-19 Pandemic. Underlying Principles and Value of Projections


• What is Public Health?
• What is Public Health?
• What is Epidemiology?
• Public Health Surveillance: Brief Overview
• Predictive Models:

Check the following resources:
• CDC,
• Coronavirus Disease 2019 in Children — United States, February 12–April 2, 2020.
• Predictive Mathematical Models of the COVID-19 Pandemic. Underlying Principles and Value of Projections
• Are We Ready for a Public Health Emergency Like the Coronavirus?
• How the Coronavirus Epidemic Has Affected Our Schools
• How Officers Can Minimize Exposure to COVID-19 Coronavirus

Check the following Videos:
• COVID-19 Animation: What Happens If You Get Coronavirus?
• 3D Animation: SARS-CoV2 Virus Transmission Leading to COVID-19
• What Coronavirus Symptoms Look Like, Day By Day
• Symptoms of Coronavirus
• 10 Things You Can Do to Manage COVID-19 At Home
• How to protect yourself against COVID-19
• Good Hand Washing is the Best Way to Stay Healthy
• Busting common VOVID-19 Myths: