The Unmasking of Masks or the Data behind the Mask and Covid-19 Prevention.

Part 1 – Preventing Infection in the Mask Wearer

It may not surprise you to learn that the idea of using masks to prevent the spread of respiratory viruses isn’t new. N95 and Surgical Masks have been tested to reduce respiratory virus infections in healthcare workers (HCWs) and, to a lesser extent, in community settings.

Let’s go to the Data –

Within the healthcare setting, the evidence is still not great. The Annals of Internal Medicine are publishing monthly updates on the use of masks to prevent Covid-19. The Annals noted that “Surgical masks probably do not reduce the risk for clinical respiratory illness (16, 21, 23), influenza-like illness (14, 15, 17–25), laboratory-confirmed viral illness (16, 17, 22, 23), and laboratory-confirmed influenza infection (14, 15, 19–21, 24, 25) compared with no mask use.”1

SARS in 2003 was caused by SARS-CoV-1, a virus similar to SARS-CoV-2, the cause of Covid-19. Even in this 2003 outbreak, “The evidence is very uncertain about the effectiveness of surgical mask use on the risk for SARS-CoV-1 infection (41, 42, 44, 47, 48, 52).”1

In the community setting, a few randomized control trials have studied the efficacy of surgical masks in reducing secondary influenza cases compared with no intervention or hand-hygiene. Typically, in these studies, after a member of a household was diagnosed with influenza, each household was randomized to into 1 of 3 groups, no intervention, hand-hygiene alone and hand-hygiene plus surgical masks. The use of surgical masks did not reduce the number of secondary influenza cases.

“Eight trials (6510 participants), including the trial described above, evaluated use of surgical masks within households with an influenza or influenza-like illness index case (child or adult) (24, 28–30, 37, 41, 48, 49). Compared with no masks, surgical masks were not associated with decreased risk for clinical respiratory illness, influenza-like illness, or laboratory-confirmed viral illness in household contacts when masks were worn by household contacts (30, 37, 48), index cases (24, 41), or both (28, 29, 49). However, some estimates were imprecise, mask-wearing adherence was limited (Supplement Table 9), and some crossover occurred. Two trials found no differences between surgical masks plus handwashing versus handwashing alone in risk for infections in household contacts of index cases (30, 48). 2

Two trials (2475 participants) of students living in university residence halls without specific contacts with cases also found no significant differences between a surgical mask versus no mask and risk for influenza-like illness (19, 20). Two trials (7851 participants) found that surgical masks, compared with no masks, were not associated with decreased risk for infections in Hajj pilgrims with or without an infected index case within the same tent (21, 23).” 2

“As noted, the evidence on mask use and risk for SARS-CoV-2 infection is very sparse.”2

A recent, retrospective study looked at households in which one or more members became infected with SARS-CoV-2. The results are strange. This study was not randomized.3 The authors reported that if people were already wearing masks when their family/friend became ill from Covid-19, masks protected people. However, if household members only started wearing masks AFTER their family/friend became symptomatic with Covid-19, the masks conferred no protection. Basically, this means some crazy folks were wearing masks at home before anyone in their family was sick. Well, these people are going to interact very differently with their family members than those who wait for a family to become ill before donning a mask. These data, actually, suggest masks do not protect, but that weird, intra-household isolation does.

If people are crazy enough to wear masks at home when no one is sick, then they are also going to do other crazy things, keeping them separated from their family members. The fact that masks did not protect household members if only put on after one family member got ill shows that masks have very little impact on blocking SARS-CoV-2 transmission. People are very contagious early in illness. So, why, if masks work, didn’t they help household members who donned them after the family member began feeling ill?

Listen, I don’t care if anyone wants to wear a mask even while swimming. I do care that we have become of society of Stasi-like mask police. Many stranges feel compelled to tell others to put a mask on or how to wear a mask. Maybe it’s a form of bizarre empowerment or of misplaced aggression. Whatever it is, it has to stop. If you are worried about contracting Covid-19, stay home, don’t tell others what to do. When a person rudely and ignorantly extolls to strangers on the importance of wearing, she/he isn’t helping anyone; she/he is only revealing their ignorance and willingness to show it.

I also do care that Americans are doing things because they were told to and that we are doing things without acknowledging the quality of data. Ironically and hypocritically, many of the people espousing the use of surgical masks have been very critical of the data on the efficacy of HCQ. They complain that the positive HCQ treatment data are from observational trials, yet, they don’t acknowledge that the data on the efficacy of masks in preventing Covid-19 are nearly non-existent and of much lower quality than the HCQ treatment data. It’s time we talked about data impartially, rationally and fairly, you know, like we are supposed to.

SMS

1. Qaseem A, Etxeandia-Ikobaltzeta I, Yost J, et al. Use of N95, Surgical, and Cloth Masks to Prevent COVID-19 in Health Care and Community Settings: Living Practice Points From the American College of Physicians (Version 1) [published online ahead of print, 2020 Jun 18]. Ann Intern Med. 2020;M20-3234. doi:10.7326/M20-3234

2. Chou R, Dana T, Jungbauer R, Weeks C, McDonagh MS. Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings: A Living Rapid Review [published online ahead of print, 2020 Jun 24]. Ann Intern Med. 2020;M20-3213. doi:10.7326/M20-3213

3. Chou R, Dana T, Jungbauer R, Weeks C, McDonagh MS. Update Alert: Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings. Ann Intern Med. 2020;173(5):W86. doi:10.7326/L20-0948