Guidelines from the Centers for Disease Control and Prevention state that those who come in close contact with someone with the coronavirus for more than 15 minutes could spread the virus regardless of whether either party wears a mask.

“Wondering what @cdcgov really thinks about masks? Their guidance on quarantining after exposure to someone with #covid explicitly states whether the infected OR exposed person wore masks doesn’t matter,” former New York Times reporter Alex Berenson tweeted Sunday.

“My mask protects no one. So does yours. Thanks for clearing that up, CDC!” he added, accompanied by screenshots of the CDC’s guidelines.

The CDC states on its Public Health Guidance for Community-Related Exposure page that those who come in close contact with people showing COVID-19 symptoms or someone who has tested positive for the virus can spread the infection whether or not they are wearing masks.

CDC states that “data to inform the definition of close contact are limited.” Factors “to consider” when defining close contact are duration of exposure, proximity to an infected person, and whether or not that person is presenting symptoms. Data for what a prolonged exposure is are iffy; however, longer than 15 minutes can be considered an operational definition, according to the CDC.

“This is irrespective of whether the person with COVID-19 or the contact was wearing a mask or whether the contact was wearing respiratory personal protective equipment (PPE),” the CDC states.

The guidance goes on to say masks “may” help people who are infected with the coronavirus from spreading it, but adds that “there is less information” if masks protect a person coming into contact with someone with the virus.

“While research indicates masks may help those who are infected from spreading the infection, there is less information regarding whether masks offer any protection for a contact exposed to a symptomatic or asymptomatic patient,” the guideline states. “Therefore, the determination of close contact should be made irrespective of whether the person with COVID-19 or the contact was wearing a mask.”

The CDC also notes that the public has not been trained on how to use PPE properly, and so it is not certain if such equipment protects them from exposure.

“Because the general public has not received training on proper selection and use of respiratory PPE, it cannot be certain whether respiratory PPE worn during contact with an individual with COVID-19 infection protected them from exposure. Therefore, as a conservative approach, the determination of close contact should generally be made irrespective of whether the contact was wearing respiratory PPE, which is recommended for health care personnel and other trained users, or a mask recommended for the general public,” the guideline states.

Wearing face masks to stop the spread of the coronavirus has sparked debates across the country this summer. The CDC and leading U.S. doctors, such as Dr. Anthony Fauci, have advocated for the use of masks, saying they are crucial in defeating the virus.

The CDC released a meta-analysis in May 2020 of 14 controlled, extended trials studying the effects of mask usage. The study found no reduction in the rate of laboratory-confirmed cases of influenza, a similar respiratory illness.

In July, Dr. Robert Redfield, director for the CDC, said, “If we could get everyone to wear a mask right now, I think in four, six, eight weeks we could bring this epidemic under control.”

“There should be universal wearing of masks,” Fauci said earlier this month. “There should be the extent possible social distancing, avoiding crowds. Outdoors [is] always better than indoors, and [you should] be in a situation where you continually have the capability of washing your hands and cleaning up with sanitizers.”

Leading Swedish epidemiologist Dr. Anders Tegnell, however, dismissed the idea that masks alone will “solve” the pandemic, citing “astonishingly weak” scientific evidence.

“The findings that have been produced through [the use of] face masks are astonishingly weak,” he told the German outlet Bild this month.

“I’m surprised that we don’t have more or better studies showing what effect masks actually have. Countries such as Spain and Belgium have made their populations wear masks, but their infection numbers have still risen. The belief that masks can solve our problem is, in any case, very dangerous,” he said.