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Mercy professor and epidemiologist Rossi A. Hassad, Ph.D., MPH, has published a series of articles on the effectiveness of wearing masks to prevent the spread of the coronavirus. Appearing in MedPage Today, the three articles address the conflicting messages about COVID-19 that have caused much confusion.

“My goal was to unmask the mask-wearing controversy,” he said.

Initially, the severe shortage of surgical masks gave rise to advice that discouraged the public from wearing masks for personal protection. Two major public health authorities, the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), expressed concern that the shortage would leave essential workers and medical personnel unprotected.

Though the problem was soon rectified, confusion about mask-wearing persisted. Shortly after Hassad’s , titled “Could Wearing a Face Mask Be a COVID-19 Game Changer?” appeared in late March, both authorities reversed their position and encouraged all citizens to wear masks when in close contact with others.

Further confusion arose over whether a mask or face covering protects the wearer. Hassad published a  in May, in which he disputed the prevailing belief, “I wear a mask to protect you, and you wear a mask to protect me.” He noted that, at minimum, “wearing a mask can reduce the viral load that can enter the respiratory system when exposed to an infected person.” He refuted the thinking that masks “could protect medical personnel but not the general public.”

Finally, in his , published in August, Hassad challenged the stance by some in the scientific community that evidence to support the effectiveness of mask-wearing should come exclusively from randomized controlled trials (RCT), which is lacking. While he acknowledged that the RCT is the “gold standard” of medical research, he noted that this is neither necessary nor appropriate. He pointed out that, in this context, other types of scientific evidence are not only available but also more relevant. According to Hassad, “from such evidence we now know that wearing a mask, social distancing, and hand hygiene, together, are effective in protecting against COVID-19.”

His advice now? “COVID-19 has challenged conventional medical and public health knowledge,” he said. “In the classroom, and as a professor of research, I emphasize the need for critical thinking, good logic, and common sense, while recognizing that there is a range of scientific evidence, and not just from randomized controlled trials. We must not let perfection be the enemy of the good.”