6 Feet: The Distance Between Science and Policy

10 min readJun 20, 2021

Emily Lin and Darshana Banka for the COVID-19 Action Coalition

By now, we all know the number: 6 feet. The US Centers for Disease Control and Prevention (CDC) recommends keeping a distance of 6 feet from others to slow the spread of COVID-19. This guideline has pervaded our lives for the past year, affecting how we work, learn, play, and shop. Whether we are picking up groceries or sitting in a lecture hall, 6 feet has been treated as the gold standard for physical distancing. But this guideline has not been devoid of pushback. Many critics have raised concerns about the 6-foot rule, questioning the rationale for this specific number and the necessity of strictly adhering to these guidelines when other protective measures are in place. In addition, other governing bodies have recommended different distances for physical distancing, such as the 3 feet suggested by the World Health Organization (1). Given the controversy surrounding the CDC’s 6-foot guideline, it’s worth examining the history behind the 6-foot rule, critiques of this number, and key takeaways from this controversy that can inform public health agencies in future public health crises.

The concept of physical distancing dates back to 1897, when German scientist Carl Flügge hypothesized that maintaining distance between sick and healthy individuals might prevent the spread of infectious diseases. The exact distance required to slow disease spread was not determined until more advanced technology was developed a few decades later. Studies in the 1940s used high-speed photography to capture the trajectory of respiratory particles during sneezes, revealing that particles traveled approximately 3 to 6 feet, before falling to the ground. During this time, scientists developed the theory that 90% of infectious particles expelled by individuals during a sneeze or cough travel less than 6 feet away (2).

While these early studies provide a basis for the 6-foot guideline, they do not justify implementing a rigid 6-foot rule to combat the COVID-19 pandemic. On the contrary, these early studies fall short in only addressing the behavior of large, infected respiratory droplets that are typically pulled down to the ground by gravity. They do not acknowledge the behavior of smaller and lighter aerosolized droplets that can travel farther away, a major route of COVID-19 transmission that may be resistant to physical distancing (3). In fact, one study conducted by MIT researchers Bazant and Bush found that the distance between individuals may not affect the risk of COVID-19 transmission, assuming expelled respiratory particles spread uniformly throughout the room and the virus spreads primarily through small, airborne aerosols. Under this well-mixed aerosol model of spread, staying 6 feet apart by itself would not prevent the virus from spreading between people because the small, infectious aerosols would have already spread through the entire room (4). An individual would still be exposed to infectious particles regardless of whether they were 6 feet or 60 feet away from an infectious individual. In these circumstances, when particles are well-mixed in the room and aerosol spread is the predominant form of transmission, physical distancing, including a distance of 6 feet, may not be very impactful (5).

The MIT researchers propose additional variables that may have a greater impact than physical distancing on the level of COVID-19 transmission: the duration of an event, event setting (i.e. indoors vs. outdoors and size of the venue), and level of ventilation and air filtration. Time spent in an enclosed area, in particular, might have a greater impact on the level of COVID-19 spread than physical distancing. In addition, an event may be safe to operate at full capacity if there is plentiful space, ventilation, and minimal time spent together. The researchers suggested that physical distancing may not even be necessary outside, as warm, infected air rises and is blown away by the wind (5)

Other studies have found that schools seem to be relatively low-risk environments for COVID-19 transmission, further questioning the necessity of ubiquitous 6-foot physical distancing. Children under 10, in particular, seem to be mostly unaffected by COVID-19 and spread the virus less efficiently than adults. This phenomenon is supported by the limited transmission among younger children and from children to parents in Britain and the Netherlands, where schools have remained open with few limitations on class size (6). Another natural experiment in Massachusetts corroborates this finding. After the Massachusetts education department recommended implementing physical distancing of 3 to 6 feet for schools reopening in the fall of 2020, schools in MA accordingly adopted a range of physical distancing policies varying from 3 to 6 feet (all mandated mask-wearing). Researchers found that the level of physical distancing (i.e. 3 vs. 6 feet) had no statistically significant effects on COVID-19 case rates (7). A study presented by Commissioner Riley in Massachusetts also concluded that there was no substantial difference in cases among students or staff with 3 feet compared to 6 feet (8). Another study published by the CDC at the end of January 2021 stated that despite students generally not maintaining the 6 feet distance, there was minimal in-school spread. Furthermore, the study also found that despite community rates reaching 40%, in-school transmission remained fairly low (9). The results of all these studies cast doubt on the rigidity with which the CDC’s 6-foot rule has been implemented in many schools.

Schools are not the only places where the 6-foot rule has been called into question. Other governing bodies have also established different physical distancing guidelines for all settings. As mentioned above, WHO suggests 3 feet of physical distancing as a general rule. The Harvard T.H. Chan School of Public Health also notes that 3 feet is acceptable provided everyone is wearing a face covering.

Excessively restrictive physical distancing policies have serious implications for the education industry, most notably the closure of elementary through high schools. The rationale of closing schools because of the rigid 6 feet rule has raised concerns about the damage done to children. In a survey of pediatric infectious disease experts, almost all of these experts agreed that elementary schools should be reopened (10). The pediatric experts believed that remote learning deprives children of developmentally relevant interaction. They also explained how school closures are affecting children’s ability to perform well academically and how these deficits could sustain over the course of their lives (11).

School closures based on the rigid 6 feet rule have additional adverse consequences: these closures have widened the pre-existing educational inequities spearheaded by uneven access to the internet for remote learning, a safe home environment, and nutrition. Such consequences disproportionately affect low-income students. According to a study co-authored by a Yale economist, the educational inequity in the US has severely impaired the academic progress of children from low-income neighborhoods, while having no significant effects on students from the richest communities. The study found that children living in the poorest 20% of US neighborhoods will experience the most negative and long-lasting effects of school closures. They highlighted that for 9th graders living in the poorest neighborhoods, the loss of skills due to remote learning translated into a decline of one letter grade. However, in the most affluent neighborhoods, they found no learning losses and even a slight improvement in grades. This improvement was explained by the increased investment of time and resources from wealthy parents to supplement their child’s remote learning. This is a privilege unavailable to low-income parents. The study also reflected on peer interaction — as it plays a huge role in academic success — and the impacts of disproportionate access for low-income children to mingle with children from other socioeconomic backgrounds, a phenomenon not seen in the case of wealthier classmates (12). Furthermore, many low-income children rely on free or discounted meals provided by schools for food and healthy nutrition levels. School closures have meant that these students’ nutritional needs are unmet, negatively affecting their ability to learn.

School closures have also been associated with a rise in children’s exposure to violence and exploitation. When schools closed down, early marriages were observed, sexual exploitations of girls and young women rose, teenage pregnancies became more common, and child labor grew (13). According to UNICEF, children are at a heightened risk of abuse, neglect, exploitation, and violence during stay-at-home orders. These occurrences were also observed during previous public health emergencies. School closures during the 2014–2016 Ebola outbreak in West Africa contributed to spikes in child labor, neglect, sexual abuse, and teenage pregnancies. Considering these consequences is of the utmost importance as state and federal governments determine whether schools should reopen (14).

Given the adverse consequences of unnecessary school closures, it is essential to re-examine the 6-foot rule. Rather than applying the 6-foot rule in all situations, a more suitable approach to COVID-19 risk and associated public health guidelines may be a graded system. Researchers from Oxford and MIT proposed one such approach: the traffic light system. This system assigns a COVID-19 transmission risk level corresponding to traffic light colors (red, yellow, and green) based on the volume of activity (e.g. silent, speaking, shouting/singing), whether masks are worn, level of ventilation, level of occupancy, and setting (i.e. indoors vs. outdoors). Rather than assigning an action a binary “safe” or “unsafe”, actions are labeled on a scale of low risk (green) to high risk (red) based on the previously mentioned variables (2). By placing actions on a continuum of risk, graded systems like the traffic light system allow individuals to adapt their health behaviors and alertness based on context. This approach protects individuals from being on constant high alert in situations that are typically low risk while encouraging them to stay vigilant in or entirely avoid scenarios where risk levels might be underestimated by rigid public health guidelines. For instance, under a graded system, individuals might not need to adhere to physical distancing guidelines as strictly in an outdoor setting with a limited number of people who are all masked. Conversely, physical distancing may have little to no impact in an indoor setting with poor ventilation even with everyone masked — if particles are spread uniformly, even those situated more than 6 feet from an infectious individual may be at high risk of contracting COVID-19.

Dr. Daniel Kamin, COVAC’s Physician Medium Advisor, also recommended that prevention measures such as 6 feet physical distancing should be graded similar to the medical guidelines grading scheme based on strength and quality of evidence. These schemes would enable school authorities, for example, to establish more adaptable rules that would keep schools open while preventing the spread of COVID-19, addressing the discrepancies in science and public policy.

The 6-foot rule is not the only guideline that warrants re-examining. The discrepancies between the 6-foot guideline and scientific and real-world studies call attention to the nature of governmental public health decision-making as a whole. First, the unclear rationales for and opaque nature of public health decision-making has led to a heightened distrust of government health agencies during the COVID-19 pandemic. For this reason, it is more important than ever for the CDC and other government public health agencies to be transparent in the rationale for their public health guidelines, as this will boost public trust and subsequent adherence to public health guidelines (15). In addition, the excessive rigidity of the 6-foot rule has demonstrated the importance of incorporating nuance into guidelines and promptly responding to a constantly evolving evidence base. Officials must tackle each crisis uniquely, carefully considering the various contexts in which individuals interact with one another to develop a nuanced rather than one-size-fits-all approach. In the context of the COVID-19 pandemic, this means considering impactful variables such as indoor/outdoor setting, duration of contact, the volume of speech, level of ventilation, and mask-wearing to determine the extent to which physical distancing is needed and subsequently whether an event can be held in person (2). While we acknowledge that more restrictive guidelines such as 6 feet may have been appropriate at the beginning of the pandemic when less was known about the modes of virus transmission, guidelines have not adapted accordingly to additional evidence that demonstrates the equal and even overriding influence of other factors in determining the risk of COVID-19 transmission. Government public health departments must be flexible and agile, staying up-to-date on the latest evidence and quickly revising guidelines as soon as the evidence indicates it (15). Otherwise, adherence to excessively restrictive guidelines that preserve physical health will lead to sacrifices in other essential pillars of society, including but not limited to mental health, business, education, and family.

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Authors: Emily Lin and Darshana Banka

Edited by: Dr. Elana Pearl Ben-Joseph

The COVID-19 Action Coalition (COVAC) is a Massachusetts-based physician-led, grassroots non-profit that advocates for evidence-based public health practices. Darshana Banka is the COVAC Medium Team Lead and a rising Senior studying at Wesleyan University. Emily Lin is the COVAC Medium Team Content Writer and a rising Senior studying at Boston University. Dr. Daniel Kamin is the COVAC Physician Medium Advisor. Dr. Elana Pearl Ben-Joseph is the COVAC Executive Director of Communications. The views expressed in this article are the authors’ own and do not reflect the official opinions of the institutions at which they work and study.

6 Feet: The Distance Between Science and Policy

Written by COVID-19 Action Coalition