CategoryGeneral Updates

Introducing Northern Mariana Islands to the U.S. COVID Coverage Map

Covid Act Now is adding the Commonwealth of the Northern Mariana Islands as the second United States territory on our COVID warning system. Check out our first U.S. territory launch of Puerto Rico.

The Commonwealth of the Northern Mariana Islands is a territory of the United States located in the Pacific Ocean. It has a population of about 51,433 (as estimated in the  2020 census data), with 90% of the population living on Saipan.

Our hope is that this coverage will give residents of the Northern Mariana Islands the power to make informed decisions on subjects from individual education to public policy, like stay-at-home and mask orders.

Covid Act Now is committed to providing individuals and policy-makers with accurate and useful information on COVID trends for all communities dealing with COVID, including U.S. territories. 

Our goal is to build a shared understanding of COVID and inform data-driven decision-making through clear, actionable, and real-time COVID risk data for every U.S resident.

This is what the Northern Mariana Islands’ COVID risk looks like today:

We continue to improve upon available data and accuracy to provide more information to the residents and visitors of the Northern Mariana Islands.

Covid Act Now is open-source, so everything can be freely shared, used, and built upon. Through our partnerships with Georgetown University Center for Global Health Science and Security, Stanford University Clinical Excellence Research Center, Grand Rounds, and more, we are always improving our data.

The following 5 Key Risk Factors are now available at Covid Act Now: Daily New Cases, Infection Rate, Test Positivity, ICU Headroom Used, and Tracers Hired.

To find the COVID data for the Northern Mariana Islands:

The Northern Mariana Islands are visible in the U.S. Coverage Map. You can also type “Northern Mariana Islands” into the search bar located above the map.

County-level data:

The Northern Mariana Islands are made up of four municipalities. We are actively working to improve upon our coverage of these municipalities to provide data that is as complete as possible.

For a description of assumptions and methodology, please see our references and assumptions document along with our data sources presentation.

To learn more about Covid Act Now, visit our about page. or for more information please reach out on our contact page or by email at info@covidactnow.org.

Types of COVID Tests

Getting tested for COVID can be confusing. 

Dr. Nirav Shah, senior scholar at Stanford University School of Medicine, describes the three different COVID tests available today: PCR, serology or antibody, and antigen tests.

At Covid Act Now, we hope that this post will give you a clear understanding of which COVID test to get, when to get tested, and how to evaluate the advantages, costs, and disadvantages of each.

PCR TESTS (Polymerase Chain Reaction)

The most widely used COVID test is called the PCR test. The PCR test is a nasal swab procedure that detects the viral genetic material of the virus. Lately, the delays to get the test results back for a PCR test can take up to a week, but these are the best tests available to detect if you have an active infection.

PCR tests are the most accurate COVID test for an active infection and cost over $100. There is generally a long wait for free testing with up to one-week turnaround times for results.

SEROLOGY TESTS

Serology tests, or, as they are more commonly known, “antibody tests,” test the blood and looks for antibodies, the proteins your body makes to fight the future infection. Antibodies are formed when you have an infection, whether or not you’ve had symptoms. 

It takes typically one to three weeks after infection for your body to make antibodies, and, as of today, we do not know how long the COVID antibodies can last in your body. 

Detection of COVID antibodies in the blood might indicate temporary immunization from the virus, but there is no definite proof so far. 

ANTIGEN TESTS

While the PCR and serology tests have pretty good test characteristics, such as sensitivity and specificity, the antigen tests are not as sensitive. This difference means that if an antibody test comes back negative, you may still have COVID. Antigen tests are generally used to confirm COVID positive diagnoses, but not to rule them out.

The antigen test is great to confirm COVID symptoms, as the PCR test results might take too long, and you might expose a lot of people during this turnaround time.

Antigen COVID tests give fast results (15 minutes), and do not have to be done in a lab or by highly trained personnel. They are inexpensive but can give false negatives, so antigen tests are best used to confirm symptoms.

Learn our 5 metrics: daily new cases, test positivity, infection rate, ICU headroom used, and contact tracing. For a description of assumptions and methodology, please see our references and assumptions document, along with our data sources presentation.

Check out our Youtube Channel for our educational videos.

To learn more about Covid Act Now, visit our about page. For more information please reach out on our contact page or by email at info@covidactnow.org.

Sign up to our alerts to stay up-to-date on the COVID risk level in your area.

Infection Rate: Explained

The Infection Rate, or “R(t),” is the number of people one infected person goes on to infect in a specific area, over a specific time. The areas we look at are county and state. The period of time we look at is while a person is contagious (able to spread COVID).

In the picture to the right, R(t) is 3.

If the R(t) is 3, one person will most likely infect three other people, and those three people will each go on to infect three more people and so forth.

R(t) is one of the most important metrics Covid Act Now tracks because it tells us how fast COVID is spreading. R(t), in combination with daily new cases, tells us about how many people are spreading COVID and at what rate. R(t) also indicates risks associated with ICU headroom used.

Here is a video that helps explain infection rate:

R(t) can change based on factors like community behavior (whether there are large gatherings) and their intervention practices (whether people wear masks and maintain social distancing.) 

How Does Covid Act Now rate R(t)?

We use 0.9 as the cutoff for a green score because, at 0.9, the number of infected people significantly declines. This is because each infected person is spreading COVID to less than one other person. 

When looking at R(t), it is important to note both value and direction. In the graph above, on March 31, the R(t) value was critical, but decreasing. On June 7, the R(t) value was high and increasing.

**The dotted line on the right represents values that have yet to be finalized.

There are significant delays between when people change their behavior and when that behavior change is reflected in R(t). When people are infected, it takes time to develop symptoms, get tested, and receive results. Because of these delays, interventions like social distancing or mask orders will take at least a few days, if not weeks, to show a decrease in R(t).

Similarly, by the time you see cases rise in your county or state, COVID has likely been spreading for days or weeks. The lower test positivity is, the more accurate R(t) measurements are because the state or county is missing fewer positive cases.

Where does our data come from for this metric?

To calculate R(t), we use new positive cases and COVID death data from The New York Times.

Infection rate is just one of several important metrics to determine how well your state or county is doing in the fight against COVID. Learn more about daily new cases, test positivity, ICU headroom used, and contact tracing. For a description of assumptions and methodology, please see our references and assumptions document, along with our data sources presentation.

Check out our Youtube Channel for our educational videos.

To learn more about Covid Act Now, visit our about page. For more information please reach out on our contact page or by email at info@covidactnow.org.

Sign up to our alerts to stay up-to-date on the COVID risk level in your area.

Daily New Cases: Explained

Daily new cases, also known as incidence in epidemiology, is the number of new COVID cases per day per unit of population. We use a more clear term, “daily new cases” that doesn’t require expert knowledge and calculate it per 100,000 people in states and counties.

Daily new cases answers the question: “How many new infections are in my area each day?” Because we can’t test our entire population, we don’t know how many total cases are in a given population. Measuring daily new cases gives us a way to gauge new COVID cases without having to test an entire population.

In the example to the right, the number of daily new cases is 3. On day one, there is a single case, but each day there are 3 new cases x per 100k people.

You can see that daily new cases, or incidence, is not a measure of the total number of cases.

While the infection rate shows how many people one person will infect while contagious, daily new cases tells us how many newly infected people are spreading at that rate. The two metrics go hand-in-hand. 

Here’s a video that helps explain daily new cases:

How does Covid Act Now rate Daily New Cases?

Covid Act Now takes an average of new COVID cases over the past seven days and divide that by 100,000. This way, we can see how many new cases there are per 100,000 people in a county or state. 

Our risk levels are based on the percent of a population that will be infected if the rate continues for one year. If critical (red) rates continue, more than 50% of a population will be infected. If high (orange) rates continue, between 10-50% of the population will be infected. If medium (yellow) rates continue, 1-10% of the population will be infected. If low (green) rates continue, less than 1% of the population will be infected. 

Let’s look at daily new cases in Nevada on July 12, below. There were 24.2 daily new cases (per 100,000) and the infection rate was 1.13.  The population of Nevada is 3.08 million, so 27.3 people per 100,000 is 841 people.

Where does our data come from for this metric?

To calculate daily new cases, we use new positive cases from The New York Times.

Daily New Cases is just one of several important metrics to determine how well your state or county is doing in the fight against COVID. Learn more about test positivity, infection rate, ICU headroom used, and contact tracing. For a description of assumptions and methodology, please see our references and assumptions document, along with our data sources presentation.

Check out our Youtube Channel for our educational videos.

To learn more about Covid Act Now, visit our about page. For more information please reach out on our contact page or by email at info@covidactnow.org.

Sign up to our alerts to stay up-to-date on the COVID risk level in your area.

Our Newest Metric: Contact Tracing

Today, Covid Act Now is excited to announce a fourth metric added to our COVID warning system: contact tracing. We will layout how we calculate whether states have sufficient contact tracing capacity, and why we think it is an important metric to assess reopening.

Why Does Contact Tracing Matter?

When people contract the virus, they do not show symptoms right away. Even as states begin to reopen, people will need to quarantine themselves if they have been silently exposed to someone with COVID.

How will they know? That’s where contact tracing comes in.

Because of this problem, it is critical that enough tracing capacity exists to rapidly trace the contacts of individuals who test positive for COVID. Those contacts can be tested, quarantined (if necessary), and asked about whom else they have come into contact with. Because exposed individuals begin infecting others, it is critical that this process be completed in less than 48 hours. If this routine of testing and tracing is done quickly and completely, it can contain COVID, as we have seen in South Korea and Taiwan, and without the need for costly lockdowns.

The White House Coronavirus Task Force’s Guidelines say that contact tracing is a “core responsibility” of states in order to be prepared to reopen. As of May 21, 27 states (CA, CT, DE, FL, HA, IL, IN, KS, KY, ME, MD, MI, MO, MT, NE, NV, NM, NY, NC, ND, OH, PA, RI, SD, WA, WV, and WI) call for contact tracing in their reopening plans. The American Enterprise Institute’s roadmap to reopening says states must massively scale up contact tracing and isolation/quarantine of traced contacts.

How Should We Measure Contact Tracing?

So how do we calculate contact tracing capacity? Experts recommend tracing contacts of someone who tests positive for COVID within 24 hours, to contain the potential of transmission. Based on conversations with practitioners and public health experts, our metric assumes that tracing all contacts for each new positive COVID case requires an average of five full-time contact tracers. 

Therefore, our contact tracing metric measures the percentage of new cases for which all contacts can be traced within 48 hours relative to available contact tracing staff in the state (assuming 1:5 new-positive-COVID-case:contact-tracing-staff ratio).

We use green if greater than 90% of the contacts can be traced within 48 hours, yellow if between 20% and 90% of the contacts can be traced within 48 hours, orange if between 7% and 20% of the contacts can be traced within 48 hours, and red if fewer than 7% of the contacts can be traced within 48 hours.

Here is an example from Wyoming:

As of June 13, Wyoming has an average of 12 new cases per day. If Wyoming needs 5 contact tracers per case, that would be 60 contact tracers necessary to trace all cases in 48 hours. Since Wyoming has 50 contact tracers, that is enough to trace 82% of cases.

What Should The Goals Be?

How did we choose our targets? Research estimates that the infection rate can be driven below 1.0 if 70-90% of cases are identified and 70-90% of those contacts are traced and isolated within 48 hours or less. Therefore, we chose 90% as the cut-off between green and yellow.

The boundaries between yellow, orange, and red are trickier. When less than 90% of positive cases have their contacts traced within 48 hours, contact tracing will likely be insufficient to contain COVID. We use 90% as the boundary between green and yellow. In the absence of expert consensus, we have set inclusive lower thresholds for yellow and orange. We peg the cut-off between yellow and orange at 20% — the number required for there to be one contact tracer per active case per 48 hours — and the cut-off between orange and red at 7%. Every state currently coded red is either currently experiencing a new outbreak or effectively has no tracing capacity.

A state can become green either by increasing the number of contact tracers, or by decreasing the number of new daily COVID infections. We hope that this new metric will help states factor contact tracing capacity into their reopening decisions.

Check out our Youtube Channel for our educational videos.

To learn more about Covid Act Now, visit our about page. For more information please reach out on our contact page or by email at info@covidactnow.org.

Exporting Covid Act Now Data to a Spreadsheet

If you’re more familiar with editing or manipulating a spreadsheet than you are with code, we have good news! You can now export the data from Covid Act Now‘s model to your favorite spreadsheet, such as Google Sheets or Microsoft Excel.

The Covid Act Now API, which we launched yesterday, exports in CSV (comma separated value) format. This format can be easily imported into a spreadsheet.

We offer forward projections on the effects of COVID-19 for 50 U.S. States and more than 2,000 U.S. Counties. The projections are available by intervention type. (For more on “inference projections,” see this blog post.)

No Action TakenSocial DistancingShelter-in-Place“Inference Projections”U.S. StatesDownloadDownloadDownloadDownloadU.S. CountiesDownloadDownloadDownloadDownload

To import into Microsoft Excel, first open Excel and select the File Menu. Then, choose Open (File => Open). Navigate and select the CSV you just downloaded.

To import into Google Sheets, first create a new blank Google Sheet. Then choose File => Open. Choose Upload and drag-and-drop the CSV file you just downloaded.

The data is updated at least every three days, and we include a “last updated” field in the download so you can ensure your data is fresh.

If you are in the government using our data to plan your response to COVID, you can reach out to us at gov@covidactnow.org. Or if you’d like to provide general feedback, thoughts, or questions, you can email us at info@covidactnow.org.

Announcing the CovidActNow.org API

Covid Act Now (CAN) is a non-profit organization of technologists, epidemiologists, and medical professionals working to model how COVID-19 will spread in each U.S. state and county. 

We published the first version of our model on March 20. Since then, 10+ million Americans have viewed the model and we’ve engaged with dozens of government officials, including the U.S. Military and White House, to assist with response planning.

Today, we are launching an API to make our data programmatically available to everyone.

Our API exposes:

Reported Data: State and county level data for confirmed cases, deaths, and hospital bed capacity. The data is collected from a number of sources, including The New York Times, and is updated daily.Forward Projections: State and county level projections for hospitalizations and deaths based on several possible interventions. This data is generated from our model.

By launching a public API, we are making the data that powers CovidActNow.org available to anyone, free of charge, under the Creative Commons 4.0 license. The data is updated daily around midnight U.S. Pacific Time, and is available in both JSON and CSV format.

You can view the documentation on GitHub.

By making this data available, we are hoping it will be a helpful input into COVID efforts such as response planning, reopening initiatives, data visualization, and the creation of new tools.

Background

Since Covid Act Now launched on March 20, our team has spent significant time refining our model. It is originally based on a traditional SEIR model by Dr. Alison Hill at Harvard, and now Dr. Rebecca Katz and her team at the Georgetown Center for Global Health Science and Security audits our work. In the past few weeks we’ve made several improvements, including adding hospitalization and severity rates, data sources, and inference projections.

Going forward, our organization will be focusing on providing data to leaders to inform their decisions around reopening safely. 

Our work is being done in the open, and you can find our model open-sourced on GitHub.

Using the API

To get data from our API, you’ll need to construct a URL with the state or county, the intervention type, and append .json or .csv. For example:

+ [ STATE CODE (CA, PA, NV) ] + [ .INTERVENTION_OPTION ] + [ .timeseries.json ]

JSON objects can be easily manipulated with code, while CSV (comma separated values) can be easily imported into Google Sheets or Excel.

The intervention choices are:

API ParameterIntervention TypeR AssumptionsNO_INTERVENTIONNone3.7WEAK_INTERVENTIONSocial Distancing1.7STRONG_INTERVENTIONShelter in Place1.1 for 4 weeks, 1.0 for 4 weeks, 0.8 for 4 weeks.OBSERVED_INTERVENTION–A dynamic forecast based on the observed data in a given U.S. state

Two notes on interventions:

OBERSERVED_INTERVENTION infers an R(t) value from recent cases, hospitalizations, and deaths in each state.To see more details on each intervention and sources for our R assumptions, please see our model references and assumptions.

For example, this link returns an aggregated list of how COVID will spread in every U.S. State based on observed data, in CSV format:

And this is Dakota County, Minnesota’s data for how COVID would spread if it reopened everything tomorrow, in JSON format. (Note that we’re constructing the URL with the FIPS code for the county.)

Open this link in your browser now to see the data:

Hopefully these examples give you a taste of how to use the API. For all the details, see the documentation on GitHub.

In the future, we intend to make more data available, including:

Additional file formats like shapefiles for GIS systems.Integrations with data visualization products, like Tableau.

Please Play Around!

In order to accelerate decision making, safely re-open the country, and, ultimately, save lives, a massive, unprecedented collaboration across government, business, and the general public is needed. 

We hope this data plays a small part in that collaboration, and we’re excited to see how it is used, visualized, integrated, and transformed to make a difference.

To learn more about Covid Act Now, visit our about page. For more information please reach out on our contact page or by email at info@covidactnow.org.

Happy coding!

Thanks to Addy Osmani, Chad Arimura, Ilya Voldarsky, Josh Dzielak, Max Lynch, Paul Irish, and Steve Wilmott for reading drafts of this post and giving feedback on the API.

Embeddable Data from Covid Act Now

We know that the data and modeling we’re doing will have the greatest impact and save the most lives if it is discoverable and actionable by the widest possible audience. Starting today, we are making our data embeddable by other publishers.

Read on to see what it looks like live.

Why We MUST Act Now

Dr. Nirav R. Shah of Stanford Medical School and covidactnow.org describes the "point of no return" and why we must act now — all from the comfort of his home as he #stayshome.

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