The New York Times has found that official tallies in the United States and in more than a dozen other countries have undercounted deaths during the coronavirus outbreak because of limited testing availability.

The New York Times is engaged in a comprehensive effort to track information on every coronavirus case in the United States, collecting information from federal, state and local officials around the clock. The numbers in this article are being updated several times a day based on the latest information our journalists are gathering from around the country. The Times has made that data public in hopes of helping researchers and policymakers as they seek to slow the pandemic and prevent future ones.

The places hit hardest

The coronavirus has moved across the country in distinct phases, devastating one region, then another.

The Northeast experienced the worst this spring, as temporary morgues were deployed in New York City. Over the summer, cases spiked across the Sun Belt, prompting many states to tighten restrictions just weeks after reopening. By early fall, the virus was filling rural hospitals in the Midwest and West as it devastated communities that had for months avoided the pandemic’s worst. And as 2021 began, the virus was simply everywhere.

Because outbreaks in group settings where large numbers of people are in close quarters have been a major driver of the pandemic, The Times has paid special attention to cases in nursing homes, food processing plants, correctional facilities and colleges.

Outbreaks among homeless Americans have not been as widespread as some feared.

Information on these cases comes directly from official releases by governments, companies and institutions. The tables below show cases that have been identified since the beginning of the pandemic, and with the exception of the table for colleges and universities, only show groups of cases where 50 or more are related to a specific site.

Cases at colleges and universities

Some universities have decided to hold most or all classes online, but many others have reopened their campuses, often with extensive procedures and rules governing behavior and testing. In August and September, as the fall term began, college towns saw some of the highest per capita case growth in the country. And by November, as cases surged across the country, tens of thousands more cases emerged at universities.

More than 6,600 cases have emerged in college athletic departments.

More than 397,000 cases among students and employees at more than 1,800 institutions have been reported over the course of the pandemic, according to a Times database. At least 90 deaths have been reported, many of them in the spring, and most of them among employees, not students.

See the complete list and details about Covid-19 cases at colleges and universities »

Cases in jails and prisons

In American jails and prisons, more than 510,000 people have been infected and at least 2,200 inmates and correctional officers have died. During interviews with dozens of inmates across the country, many said they were frightened and frustrated by what prison officials have acknowledged has been an uneven response to the virus.

After more than 2,200 prisoners tested positive, a judge told San Quentin to reduce its population.

Sandy Dowell, 51, an inmate at Swannanoa Correctional Center for Women, a prison in North Carolina, said she feared for her life if the virus spreads inside the facility. She has lung disease, asthma and high blood pressure, and said she believed prisons were disregarding the lives of inmates in their handling of Covid-19. “A life is a life, isn’t it?” she said. “I mean, isn’t everyone’s life worth something?”

In early December, Ms. Dowell tested positive for the coronavirus.

Cases at nursing homes and long-term care facilities

Coronavirus cases have been reported in more than 30,000 nursing homes and other long-term care facilities, according to data collected by The New York Times from states, counties, the federal government and facilities themselves. More than 1.1 million residents and employees of those homes have been infected, and more than 141,000 have died. That means that around 35 percent of deaths from the virus in the United States have been tied to nursing homes and other long-term care facilities.

Read more about the isolation, depression and atrophy facing many nursing home residents as lockdowns persist.

“This disease creates the potential for a perfect storm in a long-term care facility — large groups of vulnerable people living together and a highly transmissible virus that may not cause symptoms in those who care for them,” said Dr. Daniel Rusyniak, the chief medical officer for Indiana’s state social services agency.

The counts in this table of coronavirus cases at individual nursing homes were last updated as recently as Jan. 12, 2021. Since then, we have continued to update state-level totals for cases and deaths in long-term care facilities.

Cases at food production facilities

Early in the pandemic, cases emerged by the hundreds in food processing facilities. The outbreaks disrupted the country’s meat supply and led some of the hardest-hit plants to temporarily close.

In July, the Centers for Disease Control and Prevention reported more than 16,000 infections and 86 deaths tied to meat and poultry processing. But those numbers are almost certainly an undercount. Only 28 states provided data to the C.D.C., and many states and food processing companies have refused to provide case totals. Other large outbreaks have emerged on farms, in fruit or vegetable processing facilities and at plants where pet food is made.

Other significant clusters

The coronavirus has followed Americans wherever they gathered, spreading early this year, on cruise ships and at business conferences. As the country has reopened, new clusters have emerged at churches, restaurants and workplaces. Read more here about some of the country’s less-noticed coronavirus clusters. Because many states do not provide information about where the virus spread, no listing of clusters and local outbreaks will be complete.

About the data