A cumulative 511,000 lives could be lost from COVID-19 in the United States by the end of February 2021, a new prediction study reveals.
However, if universal mask wearing is adopted — defined as 95% of Americans complying with the protective measure — along with social distancing mandates as warranted, nearly 130,000 of those lives could be saved.
And if even 85% of Americans comply, an additional 95,800 lives would be spared before March of next year, researchers at the University of Washington Institute for Health Metrics and Evaluation (IHME) report.
The study was published online October 23 in Nature Medicine.
“The study is sound and makes the case for mandatory mask policies,” said Arthur L. Caplan, PhD, a professor of bioethics at NYU Langone Health in New York City, who frequently provides commentary for Medscape.
Without mandatory mask requirements, he added, “we will see a pandemic slaughter and an overwhelmed healthcare system and workforce.”
The IHME team evaluated COVID-19 data for cases and related deaths between February 1 and September 21. Based on this data, they predicted the likely future of SARS-CoV-2 infections on a state level from September 22, 2020, to February 2021.
An Optimistic Projection
Lead author Robert C. Reiner Jr and colleagues looked at five scenarios. For example, they calculated likely deaths associated with COVID-19 if adoption of mask and social distancing recommendations were nearly universal. They note that Singapore achieved a 95% compliance rate with masks and used this as their “best-case scenario” model.
An estimated 129,574 (range, 85,284–170,867) additional lives could be saved if 95% of Americans wore masks in public, their research reveals. This optimistic scenario includes a “plausible reference” in which any US state reaching 8 COVID-19 deaths per 1 million residents would enact 6 weeks of social distancing mandates (SDMs).
Achieving this level of mask compliance in the United States “could be sufficient to ameliorate the worst effects of epidemic resurgences in many states,” the researchers note.
In contrast, the proportion of Americans wearing masks in public as of September 22 was 49%, according to IHME data.
Universal Mask Use Unlikely
“I’m not a modeling expert, but it is an interesting, and as far as I can judge, well-conducted study which looks, state by state, at what might happen in various scenarios around masking policies going forward — and in particular the effect that mandated masking might have,” Trish Greenhalgh, MD, told Medscape Medical News.
“However, the scenario is a thought experiment. Near-universal mask use is not going to happen in the USA, nor indeed in any individual state, right now, given how emotive the issue has become,” added Greenhalgh, professor in the Nuffield Department of Primary Care Health Sciences at Oxford University, UK. She was not affiliated with the study.
“Hence, whilst I am broadly supportive of the science,” she said, “I’m not confident that this paper will be able to change policy.”
Other “What If?” Scenarios
The authors also predicted the mortality implications associated with lower adherence to masks, the presence or absence of SDMs, and what could happen if mandates continue to ease at their current rate.
For example, they considered a scenario with less-than-universal mask use in public, 85%, along with SDMs being reinstated based on the mortality rate threshold. In this instance, they found an additional 95,814 (range, 60,731–133,077) lives could be spared by February 28.
Another calculation looked at outcomes if 95% of Americans wore masks going forward without states instituting SDMs at any point. In this case, the researchers predict that 490,437 Americans would die from COVID-19 by February 2021.
A fourth analysis revealed what would happen without greater mask use if the mortality threshold triggered 6 weeks of SDMs as warranted. Under this ‘plausible reference’ calculation, a total 511,373 Americans would die from COVID-19 by the end of February.
A fifth scenario predicted potential mortality if states continue easing SDMs at the current pace. “This is an alternative scenario to the more probable situation where states are expected to respond to an impending health crisis by reinstating some SDMs,” the authors note. The predicted number of American deaths appears more dire in this calculation. The investigators predict cumulative total deaths could reach 1,053,206 (range, 759,693–1,452,397) by the end of February 2021.
The death toll would likely vary among states in this scenario. California, Florida, and Pennsylvania would like account for approximately one third of all deaths.
All the modeling scenarios considered other factors including pneumonia seasonality, mobility, testing rates, and mask use per capita.
“I have seen the IHME study and I agree with the broad conclusions,” Richard Stutt, PhD, of the Epidemiology and Modelling Group at the University of Cambridge, UK, told Medscape Medical News.
“Case numbers are climbing in the US, and without further intervention, there will be a significant number of deaths over the coming months,” he said.
Masks are low cost and widely available, Stutt said. “I am hopeful that even if masks are not widely adopted, we will not see as many deaths as predicted here, as these outbreaks can be significantly reduced by increased social distancing or lockdowns.”
“However this comes at a far higher economic cost than the use of masks, and still requires action,” added Stutt, who authored a study in June that modeled facemasks in combination with “lock-down” measures for managing the COVID-19 pandemic.
Modeling study results depend on the assumptions researchers make, and the IHME team rightly tested a number of different assumptions, Greenhalgh said.
“The key conclusion,” she added, “is here: ‘The implementation of SDMs as soon as individual states reach a threshold of 8 daily deaths per million could dramatically ameliorate the effects of the disease; achieving near-universal mask use could delay, or in many states, possibly prevent, this threshold from being reached and has the potential to save the most lives while minimizing damage to the economy.’ “
“This is a useful piece of information and I think is borne out by their data,” added Greenhalgh, lead author of an April study on face masks for the public during the pandemic.
You can visit the IHME website for the most current mortality projections.
Caplan, Greenhalgh, and Stutt have disclosed no relevant financial relationships.
Nat. Med. Published online October 23, 2020. Full text
Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology and internal medicine. Follow Damian on Twitter: @MedReporter.