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Testing Hub

Testing

Overview

The COVID-19 pandemic has caused unprecedented public health and economic crises. In the coming weeks and months, viral tests for the presence of COVID-19 infection as well as serological tests for antibodies and potential immunity will be critical to measure the spread of the disease. Governments, businesses, and families will rely on data from these tests as they make decisions around the path forward. However, local testing data are not currently publicly available, and a comprehensive set of these data—paired with expert analysis and guidance—does not exist in one place. This initiative seeks to fill that gap.

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Testing Tracker

Testing tracker

See changes in new cases and testing capacity in all 50 states

Understanding COVID-19 outbreaks across U.S. states and regions based on three important metrics.

Testing tracker

New tests per 1,000 people

A state-by-state comparison.

Testing tracker

Have new tests declined from previous week?

A state-level look at weekly changes in testing rates.

Testing tracker

Percent of new tests that are positive

See which states meet or exceed test positivity rates recommended by the World Health Organization.

Testing Insights

Johns Hopkins experts are working to fill the void of publicly accessible COVID-19 testing data. This initiative reflects an interdisciplinary collaboration between several groups at Johns Hopkins University: The Bloomberg School of Public Health, Applied Physics Laboratory, Center for Health Security, Center for Systems Science and Engineering (CSSE) in the Whiting School of Engineering, and the Centers for Civic Impact, with generous support from Bloomberg Philanthropies and the Stavros Niarchos Foundation.

Testing insights

Which U.S. states meet WHO-recommended testing positivity levels?

The World Health Organization recommends that states strive for 3-12% test positivity, as an indicator that states are conducting enough tests. Which states are testing enough to meet this goal?

Testing insights

International comparison of positivity rates and tests per capita

Testing insights

Cases, Deaths, and Testing in All 50 States

Testing insights

Daily State-by-State Testing Trends

Johns Hopkins center for Health Security

Johns Hopkins Experts

Tracking serology-based tests for COVID-19

The Johns Hopkins Center for Health Security is tracking the development and availability of serology tests. Serology tests are blood-based, and can be used to determine whether individuals have been exposed to a particular pathogen by looking at antibodies, or proteins produced by the body in response to an infection. Serology tests can be helpful in determining whether someone was infected with the SARS-CoV-2 virus, which causes COVID-19, regardless of whether they ever developed symptoms of the disease. Serology tests can better quantify the number of cases of COVID-19 in the population, including those that may be asymptomatic or have recovered.

Questions about Testing

Who started the Testing Insights Initiative and why?How is COVID-19 diagnosed?What are limitations to COVID-19 diagnostic tests?Who should be tested for COVID-19?
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Latest News & Resources

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news | August 4, 2020

Business Insider: US coronavirus testing is going in the wrong direction. Declines could partially explain why cases seem to be dropping.

Testing per capita has declined steadily in at least six states over the last two weeks. Meanwhile, test positivity rates have risen in 32 states during the same time frame, according to data from Johns Hopkins University.

news | July 22, 2020

Vox: What scientists are learning about how long COVID-19 immunity lasts

experts | July 21, 2020

MSNBC: Public health experts discuss need for increases in testing, reductions in delayed results

Dr. Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security, on how testing delays are hindering efforts to control the outbreak.

experts | July 8, 2020

PBS Newshour: Why is the U.S. struggling to test everyone who needs it?

William Brangham talks to Dr. Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Center for Health Security, on how virus testing in the United States has consistently missed the mark.

news | June 24, 2020

'Grave concerns': COVID-19's surge in Sunbelt states shows the virus, not testing, to blame

experts | June 22, 2020

Washington Post: No, more testing doesn’t explain the rise of COVID-19 cases in the U.S.

Jennifer B. Nuzzo, epidemiologist with the Johns Hopkins Bloomberg School of Public Health’s Center for Health Security, on increased COVID-19 testing and positivity rates in some states.

experts | June 18, 2020

New Report: Developing a National Strategy for SARS-CoV-2 Serosurveys in the United States

The Center for Health Security at the Bloomberg School of Public Health has released a new report that provides recommendations for the U.S. government and states for performing serosurveys (antibody studies) for SARS-CoV-2 infections with the goal of deriving value from them in a national action plan.

experts | June 13, 2020

The US government needs to validate antibody tests

Dr. Gigi Gronvall and Dr. Rachel West, both of the Johns Hopkins Bloomberg School of Public Health, on why serology tests must be as dependable as possible for use in public health decision making.

experts | June 12, 2020

Testing Trends Tool

Track and compare changes in new cases and testing capacity in all 50 states through charts and maps.

news | June 2, 2020

Protesting in a pandemic: COVID-19 testing sites shut down amid national unrest

experts | May 29, 2020

Bloomberg: Antibody Tests Don’t Tell If Protected From Reinfection

Johns Hopkins Bloomberg School of Public Health Professor Andrew Pekosz discusses antibody testing, and wearing masks as part of one step of protection against COVID-19.

experts | May 28, 2020

CDC undercuts utility of antibody tests as key COVID-19 tool

Dr. Amesh Adalja, senior scholar at the Johns Hopkins University Center for Health Security, discusses new guidance from the CDC that COVID-19 antibody tests are not a reliable source of information about a person's past or future relationship to the coronavirus.