The Time to End Los Angeles’ General Mask Mandates is Now

February 11, 2022

Los Angeles County reinstated indoor mask mandates on July 17, 2021. It required adults and all children 2 years of age or greater to mask when indoors. LA County Public Health justified the reinstatement of the mask mandate on the grounds that a significant fraction of Los Angeles county population was still susceptible to COVID (about 65% of the population 5 years or older had received at least one dose of the vaccine), COVID cases were rising, and that mask mandates were an effective intervention for increasing community masking and reducing COVID-19 infections.

The figure below shows the cumulative number of confirmed COVID-19 cases in Los Angeles County before and after the reinstatement of the mask mandate. It is clear from these data that infections continued to increase despite the imposition of the mask mandate suggesting limited or no efficacy of the mask mandate.

Those data from Los Angeles County are also consistent with the scientific literature that finds limited or no efficacy of interventions designed to decrease COVID-19 through increased community masking. To date, there have been two randomized-controlled experiments, the gold standard in scientific research, in evaluating the effectiveness of interventions for promoting community mask wearing on COVID-19 infections.

The first study, conducted in Denmark randomized participants into two groups, mask group and control group. Participants in the mask group were instructed to wear a mask when outside the home and received fifty 3-layered surgical masks. About half of the participants reported wearing masks as recommended. Participants in the control group received no intervention. The primary end point was new SARS-CoV-2 infections both diagnosed and undiagnosed, in the post intervention period. The study found that the rate of infections was 3 in 1000 lower in the mask group than control group, however this difference was not statistically significant. In other words, the researchers could not tell whether the difference was due to chance or due to mask wearing. Interestingly, when the researchers only analyzed data for the people in the mask group who reported wearing masks, the difference in the rates of infection narrowed to being 1 in 1,000 lower in the mask group.

Another study, conducted in Bangladesh, randomized villages into two groups. A mask group where participants were encouraged to wear masks and provided free masks and a control group that received no intervention. This study showed that those in the mask group were much more likely to wear a mask. The study measured symptomatic COVID-19 infections but could not tell whether the infections occurred before or after the study team implemented the mask intervention. It showed that the risk of symptomatic COVID-19 infection was 7 in 10,000 lower in the mask group (about 10% reduction relative to control group) and this difference was statistically significant. That is, the lower risk of infection in the mask group was likely due to the intervention and not due to chance. However, the study found no statistically significant protective effect for those below 50 years of age and found no statistically significant protective effect of cloth masks.

There have also been several randomized-controlled trials conducted prior to the pandemic comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illnesses in healthcare workers (2 trials) and in the general community (7 trials). A recent review of those studies noted: “There is low certainty evidence from nine trials (3507 participants) that wearing a mask may make little or no difference to the outcome of influenza‐like illness compared to not wearing a mask (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.82 to 1.18). There is moderate certainty evidence that wearing a mask probably makes little or no difference to the outcome of laboratory‐confirmed influenza compared to not wearing a mask (RR 0.91, 95% CI 0.66 to 1.26; 6 trials; 3005 participants).”

Therefore, both the scientific literature and data from Los Angeles County suggest limited or no efficacy of mask mandates in reducing COVID-19 infections.

Furthermore, the mask mandate has potential harms. Daily use of disposable surgical masks by millions of Los Angeles residents has an adverse environmental impact resulting in substantial marine litter and tons of excess waste in landfills. Secondly, masks are costly, disproportionately affecting those of lower socioeconomic status. Finally, mask mandates affect quality of life as they impinge on autonomy and mask wearing is fundamentally changing the way we work, educate our children, and interact with others.

Early in the pandemic, when there were no treatments or vaccines available, community masking was supported based on the precautionary principle. The idea was that even though we didn’t have evidence that masks work in reducing COVID-19 infections, policymakers should still encourage people to wear masks on the ground that we have little to lose and potentially something to gain from mask wearing. However, this approach cannot be justified today as we not only have evidence on the limited effectiveness of masks but also have vaccines and treatments to protect the population from death or hospitalization from COVID-19.

Fortunately, since the introduction and widespread availability of vaccines, 98.6% of Angelenos at greatest risk of severe disease, hospitalization, and death — those age 65 years and older — have received at least one dose of the COVID-19 vaccine. Estimates from seroprevalence studies conducted by NIH and CDC suggest that about 95% of southern California residents have antibodies against the spike protein (the protein the virus uses to infect cells) of coronavirus due to prior infection or vaccination. Evidence also suggests that these antibodies do not wane overtime. Having COVID-19 antibodies significantly reduces risk of infection, with rates of hospitalization similar to or lower than seasonal flu.

Additionally, 2022 has brought the availability of new antiviral therapies, both antibodies for infusion and oral antiviral pills. Those treatments reduce the risk of hospitalization between 70–90% and are increasingly available. Given the context of widespread immunity and treatment, it is not only time to change our pandemic strategy but to accelerate the lifting of mandates that have little benefit but do have documented harm.

Given the lack of proven benefit to community-wide mask mandates on reducing the population-level spread of infection, the new community context of high levels of protective immunity against severe disease, hospitalization and death, we call on the Los County Department of Public Health to immediately rescind current indoor mask mandates and allow for individual choice.

Mask mandates for children are the most egregious. COVID-19 is less of a threat to children than accidents or the common flu. The survival rate among American children with confirmed cases is approximately 99.99%; remarkably, recent studies find an even higher survival rate. The WHO does not recommend masking in those under age 6years of age due to the absence of proven benefit and the potential harms associated with social neurocognitive development. Most European countries do not require mask use for children 12 years of age or less and the European CDC does not recommend such requirements. A recent online petition signed by over 1,000 medical and public health professionals also calls for elimination of mandated mask use in children.

There are situations where use of a high-grade medical mask is likely beneficial — among healthcare workers taking care of infected individuals, among those recently recovering from infection, among those unvaccinated visiting a highly vulnerable individual or groups of individuals, but in general, routine mask use should be abandoned.

Angelenos have bravely complied with various restrictions for nearly 2 years, some commonsensical and others with no rationale. The time to end the indoor mask mandate is now.

Jeffrey D. Klausner, MD, MPH
Clinical Professor of Medicine, Population and Public Health Sciences
Keck School of Medicine of the University of Southern California
Former CDC Medical Officer and San Francisco Deputy Health Officer

Neeraj Sood, PhD
Professor of Public Policy, Sol Price School of Public Policy
Senior Fellow and Director of COVID Initiative,
Schaeffer Center for Health Policy and Economics
University of Southern California

James E. Enstrom, PhD
Professor of Epidemiology, Retired
University of California, Los Angeles

Noah Kojima, MD
Senior Resident, Internal Medicine, David Geffen School of Medicine
University of California, Los Angeles

Catherine A. Sarkisian MD, MSHS
Professor, David Geffen School of Medicine at UCLA

Professor James E. Moore, II
Viterbi School of Engineering and Price School of Public Policy
University of Southern California

Gabe Vorobiof, MD FACC FASE
Associate Professor of Medicine and Cardiology
David Geffen School of Medicine at UCLA

Professor Avanidhar Subrahmanyam, PhD
The Anderson School
University of California, Los Angeles

Carole H Browner, Ph.D., M.P.H.
Professor, David Geffen School of Medicine
University of California, Los Angeles



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Jeffrey Klausner

Professor of Medicine, Population and Public Health Sciences, USC Keck School of Medicine; Former CDC Medical Officer