Twitter's coronavirus rules face new test: Elon Musk

(CNN) Just days after Twitter announced new rules to crack down on tweets spreading misinformation about coronavirus, the company faced a test from a high-profile source: Elon Musk.

On Thursday, Musk, the CEO of Tesla (TSLA) and SpaceX, tweeted the false claim that children are "essentially immune" to the virus. Twitter did nothing.

A Twitter spokesperson told CNN Business on Friday that it reviewed Musk's tweet and determined it did not break its rules. Yet, when Twitter unveiled its new rules on Monday, it specifically referenced misinformation about children and the coronavirus as an example of content that would need to be removed.

As an example of a tweet that would violate its rules, Twitter had provided the following example: "COVID-19 does not infect children because we haven't seen any cases of children being sick."

Musk's assertion on Twitter was contradicted at a White House podium on Friday by global health expert Dr. Deborah Birx, the White House coronavirus task force response coordinator.

"To the moms and dads out there that have children with immunodeficiencies or other medical conditions, we don't know the level of risk," Birx said. "There just is not enough numbers at this time to tell them if they are at additional risk or not in the same way that adults are."

Birx, who was speaking generally and not responding to Musk's tweet, added: "No one is immune. We know it is highly contagious for everyone."

According to a study published online in the medical journal Pediatrics on Monday, children in China infected with novel coronavirus showed less severe symptoms than adults, though infants and toddlers were vulnerable to moderate and severe infection.

The study examined 731 confirmed and 1,412 suspected cases of COVID-19 in children. Out of the combined 2,143 cases, one child, a 14-year-old boy, died and nearly 6% of cases were severe, compared with 18.5% of adults experiencing severe symptoms.

Young children, particularly infants, were vulnerable to COVID-19 infection, the authors of the study said. Nearly 11% of cases were severe and critical for infants less than 1 year old.

Musk previously downplayed concerns about the coronavirus outbreak and kept Tesla's California factory open despite a shelter-in-place order.