Apple is cracking down on apps related to the COVID-19 coronavirus outbreak that aren't from recognized institutions like governments or hospitals, iPhone developers told CNBC.

Four independent developers told CNBC that Apple rejected their apps, which would allow people to see stats about which countries have confirmed cases of the COVID-19 coronavirus. Some of these apps used public data from reliable sources like the World Health Organization (WHO) to create dashboards or live maps. Some developers asked not to be named to avoid further complications with Apple's review process.

One developer said an Apple employee explained over the phone that anything related to the coronavirus must be released by an official health organization or government. Another developer got a written response that "apps with information about current medical information need to be submitted by a recognized institution," according to a screenshot seen by CNBC.

Apple has been specifically evaluating coronavirus apps to prevent the spread of misinformation. It looks at both where the health data comes from and whether the developers represent organizations that users can trust to publish accurate data, like governments or health-focused organizations, according to a person familiar with the matter.

The restriction appears to be working, as search results show few apps about the outbreak and no obvious spam. But it could also reduce the availability of software that would enable iPhone users to track the outbreak, and raise fairness questions about who is allowed to develop apps for iPhones.

The move comes as big tech companies have grappled with the effects of misinformation related to the coronavirus outbreak on their platforms. Last month, Amazon warned sellers that it would take down listings for products that claim to kill coronavirus. Facebook CEO Mark Zuckerberg wrote on Tuesday that he's "focused on making sure everyone can access credible and accurate information" about the outbreak and is removing content with conspiracy theories. Google presents information from the World Health Organization at the top of Google searches about the coronavirus in a special module and has banned ads for anti-coronavirus products.

"Right now the technology industry is working very hard to ensure the platforms are not being used to provide people with false or, even worse, dangerous information about the coronavirus," said Morgan Reed, president of the App Association, an industry group that represents app developers. "We are seeing significant pressure inside and outside to halt applications and advertisements before they harm citizens."

A search for "coronavirus" on the App Store on Wednesday in the United States revealed mostly benign results.

The top result was a Portuguese-language app about the outbreak published by the Brazilian government. Below that was an unrelated wallpaper app, a game that looks similar to top-grossing epidemic game Plague Inc, the Canadian Broadcasting Corporation's app, the Epoch Times, and an app with COVID-19 information published by Unbound, a developer of medical apps.

The top result for "COVID 19" is a "virus tracker" from a developer called Healthlynked with WHO figures and maps charting where confirmed cases have been. It's currently No. 2. for medical apps on Apple's app store in the United States. Below that is the Unbound app and several Chinese-language apps.