In San Francisco — where more than 500 people have tested positive and eight have died from COVID-19 — public health officials have released little more than basic statistics on the spread of the coronavirus for months, despite calls for more information on how the pandemic is affecting local communities and hospitals.

As of Saturday afternoon, no information was prominently posted on the ages or genders of people who had died of the respiratory virus, or whether they had underlying medical conditions. If a cluster of cases had broken out in a neighborhoocod, or a hospital was seeing a surge in critically ill patients, it was impossible to know from looking at the city’s website.

San Francisco isn’t the only county in California that has tightly restricted certain information about coronavirus cases. Some local health departments have released few details as they weigh patient-privacy concerns with the need for transparency amid the pandemic. But researchers and politicians say these restrictions go too far, impeding the public’s ability to understand the scope of the unprecedented health crisis and adequately respond.

“It is a complete mess,” said Dr. John Ioannidis, a professor of medicine, epidemiology and population health at Stanford University, who has written about the danger of making decisions during the pandemic without more reliable information. “We are blind and scattered in our data right now. And we need to have eyes on the epidemic because if you don’t have eyes, you don’t know what to do next.”

As pressure has mounted, the California Department of Public Health and a number of counties began sharing more information with the public last week.

The state health department unveiled a website offering county-by-county statistics on how the coronavirus has begun to strain hospitals, including numbers of critically ill patients who have been admitted to intensive care units. Santa Clara, Sacramento, Contra Costa and Yolo counties, among others, also released new details in online dashboards.

On Friday, San Francisco Supervisor Aaron Peskin said county public health officials told him they would soon post more detailed information online. He has asked the health department to publish daily reports that would include information on hospital admissions, available hospital beds, tests performed by age group and test results.

The department did not immediately respond to questions from The Chronicle.

“The public has a right to know this information,” Peskin said. “This isn’t classified information, and it doesn’t violate patient confidentiality, so it seems to me that this is information that an open, democractic society shouldn’t be afraid of.”

In general, information that would personally identify a living or deceased patient can be barred from being released, according to medical privacy laws. But other information pertaining to testing turnarounds and results, demographics, geography or hospital capacity and caseloads is not legally restricted from being published, according to health experts.

Florida provides basic demographic information for every patient infected with the respiratory virus and displays data by ZIP code. New York City reports positive cases and deaths by borough and includes whether people who died had underlying medical conditions, in addition to information about their age and sex.

But in California, the approach has been more restrictive. Although the state has been a national leader in some respects during the pandemic — instituting the first state-level shelter-in-place policy — it has faced criticism by frontline medical professionals, epidemiologists and the public for refusing to release important information about coronavirus testing, cases and hospitalizations.

The state publishes a general breakdown of COVID-19 deaths by age and gender, but there is little consistency statewide in the release of coronavirus information. A Chronicle review of local health websites last week found that only about 15 counties provided easy-to-access details on COVID-19 cases at the city level, meaning it was impossible to determine beyond the county level where the virus had been detected in much of California.

Data on how many tests are outstanding, or have come back negative, is sparse. And very limited demographic details, if any, are reported on the people who are becoming seriously ill or dying, significantly diminishing the ability to understand how the virus is moving through communities and hospitals and who it’s impacting the most.

Tracking such information is difficult for stretched health agencies that are operating on budgets stripped down after the 2008 recession.

“We have a radically decentralized, underfunded public health infrastructure, and this is the consequence of that,” said Dr. Steven Goodman, a professor of epidemiology and population health at Stanford University.

The data released by the California Department of Public Health last week was the first step toward creating a central repository for COVID-19 cases. It provides the daily count of positive tests and deaths by county, as well as the number of people who have been hospitalized or placed in the intensive care unit by the virus.

Because testing remains inconsistent, hospitalizations are a reliable way to measure the severity of the virus’ impact on people and medical facilities, which gives the public a better understanding of where resources, such as staff and equipment, should be directed.

“In an effort to be transparent, we are continually assessing what information can and should be made public,” a California Public Health Department representative said in a statement, noting that the state might provide more demographic and geographic information on cases in the future.

Even these efforts, however, fall short of what some health experts said would be a thorough report on the evolving spread of COVID-19, the disease caused by the coronavirus. Specific geographic data could become important as the outbreak eventually begins to wind down, so people can avoid “hot spots” as they move about.

The state’s new county-level data on hospitalizations also doesn’t show daily admissions over time, which are crucial to understand the progression of the virus and how well the shelter-in-place policies are working, Goodman said.

“We shouldn’t have to wait for the governor to make announcements about trends,” he said. “Researchers and public health officials should be able to look at the curve for the past week or past month and see those trends for deaths or hospitalizations.”

Along with the state, several counties have also increased how much they tell the public about COVID-19. Over the past few weeks, Sacramento, Contra Costa and Orange counties joined others that post city-by-city data.

Yolo County began publishing city-level information Wednesday, after initially choosing not to disclose it. Local health officials waited until they had enough confirmed cases spread out across the region to protect people’s privacy, said spokeswoman Jenny Tan.

“We wanted to protect not only their identity but also their emotional and mental state,” Tan said. “It’s a big thing to say I’m a confirmed case of COVID-19 in such a small community.”

Santa Clara County unveiled a comprehensive data portal last week that shows not just case and hospitalization tallies, but also how many ICU beds and ventilators are available and the status of tests. The county plans to update the site daily to show how prepared the health care system is for a potential surge in COVID-19 cases.

Reports at the city level, however, are not available, making it impossible to know how cases are spread across dozens of communities stretching from Palo Alto to Gilroy.

Health officials throughout the Bay Area have said that posting city-level information could increase discrimination and ostracize communities. Some epidemiologists also believe the data could mislead people and create a false sense of security because it may actually show where people have access to tests, not where they’re getting sick.

In Los Angeles, the neighborhoods with some of the highest rates of confirmed COVID-19 cases are wealthy enclaves like the Hollywood Hills and Bel-Air where people are more likely to be able to get commercial tests, according to an analysis by Crosstown at the University of Southern California.

“The truth is, so few people are being tested, that if I told you there’s one case in your city, there could be 100 cases in your city,” said Dr. Bela Matyas, Solano County’s public health officer. “If I told you there’s zero, there could still be 100 cases and we would never know.”

Santa Clara County Supervisor Dave Cortese has asked local health officials to provide information on confirmed cases in each census tract — a level of detail that some fear could press up against a patient’s privacy.

Cortese said the information would be particularly useful to people who continue to work in the community. One homeless person has died of COVID-19 in Santa Clara County, for example, and knowing where he or she lived would help outreach workers stay safe, he said.

“People could do a better job of protecting themselves and protecting others if they knew just basic information about where the hot spots are,” he said. “If some corner in Milpitas had an infection cluster, wouldn’t it behoove all of us to let people know to social distance from that area?”

Solano County’s online coronavirus statistics dashboard includes hospitalization and age data. The county does not post city-level data, but plans to if the number of cases reaches a certain threshold.

Matyas, the county public health officer, said the information may help alleviate anxiety among the public, but the data they’re collecting are “scattered everywhere,” making it difficult or impossible to paint a comprehensive picture.

“I don’t fault anyone for wanting more information, this is really scary, and knowledge can help diminish that fear,” Matyas said. “We’re not averse to providing information as transparently as possible, we’re just (always) having to weigh the risks and benefits of doing it.”

San Francisco Chronicle staff writer Trisha Thadani contributed this report.

Joaquin Palomino and Cynthia Dizikes are San Francisco Chronicle staff writers. Email: jpalomino@sfchronicle.com, cdizikes@sfchronicle.com Twitter: @JoaquinPaolomino, @cdizikes