Updated: Jun 12, 2020
The lack of robust science behind the current social distancing rules contributes to uncertainty and raises legitimate questions about expert advice.
In the absence of a vaccine and effective medications to treat SARS-CoV2, the options currently recommended to prevent the its spread are social distancing, wearing masks, and social behavior such as frequent hand washing and following a strict cough and sneeze protocol. Social distancing is viewed as the most effective approach in preventing the spread of the novel coronavirus. However, in different countries, there are different rules for social distancing. It is important to look at the variations in social distancing rules in different countries and examine the scientific basis for social distancing in this case.
Let us first start with the World Health Organization (WHO)'s guidelines. The WHO recommends at least 1metre (3 feet) of social distancing. Most countries around the world follow the WHO guidelines. For instance, India currently recommends 1 meter. By contrast, Australia suggests keeping 1.5 meters away from others wherever possible. The United States and Japan have adopted a 1.8 meters rule. The Center for Disease Control (CDC) in the U.S. recommends staying at least 6 feet (about 2 arm's length or 1.8 meters) from other people. Canada follows the same rule of 2 arm's lengths. However, it says 2 arm's length is approximately 2 meters, rather than exactly 1.8 meters. The United Kingdom and New Zealand's governments advised their citizens to maintain a distance of 2 meters from others.
The existence of different rules for social distancing across countries for the same disease may raise questions in the public about the validity of expert knowledge and whether there is clear scientific evidence in support of public health measures. It is likely that questions may naturally arise about the rationale behind the current social distancing rules and where exactly it came from.
The origin of social distancing rules can be traced back to late 1900's and is largely credited to the work of Carl Flügge and William F. Wells. Carl Flügge (12 September 1847 – 10 December 1923) was a German bacteriologist and hygienist. He had done extensive research on the transmission of infectious diseases such as malaria, tuberculosis, and cholera. In the 1890's, he demonstrated that even during "quiet speech" minute respiratory droplets are sprayed in the air. These droplets are presently known as Flugge's droplets. Later on, in the 1930's, William F. Wells, a Harvard researcher who studied tuberculosis transmission, differentiated respiratory droplet emissions into “large” and “small” droplets. According to Wells, as highlighted by Lydia Bourouiba, “isolated droplets are emitted upon exhalation. Large droplets settle faster than they evaporate, contaminating the immediate vicinity of the infected individual. In contrast, small droplets evaporate faster than they settle.”
This dichotomy has become the basis of current social distancing rule. According to the WHO, the following characteristics applies to the COVID-19 infections: “Respiratory infections can be transmitted through droplets of different sizes: when the droplet particles are >5-10 μm in diameter they are referred to as respiratory droplets, and when then are <5μm in diameter, they are referred to as droplet nuclei. According to current evidence, COVID-19 virus is primarily transmitted between people through respiratory droplets and contact routes... Droplet transmission occurs when a person is in close contact (within 1 m) with someone who has respiratory symptoms (e.g., coughing or sneezing) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposed to potentially respiratory droplets.”
It appears that as per the WHO guidelines there is no rationale behind more than the 1 meter social distancing rule. Robert Dingwall of the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) in the UK has emphasized, “there has ‘never been a scientific basis for two meters’, naming it a ‘rule of thumb’.” He has further stated that “advice to keep two meters apart while social distancing was ‘conjured up out of nowhere’.” At the time of writing, there were reports that the UK government was considering to reduce social distancing to one meter. In contrast, the Indian government, which recently lifted the lockdown, suggested increasing social distancing from one meter to two meters (6 feet).
It is evident that there is no consensus on social distancing rules and guidelines continue to vary across different jurisdictions. In addition to controversies on whether to wear a mask, the disparities in social distancing rules raise legitimate questions on the value of expert advice in deciding what public health measures can help curb the spread of COVID-19. The discrepancy also contributes to the already existing confusion among the public as to what is true and false about this disease and the factors that influence its spread. There is a greater need for harmonization of expert advice, especially given the free flow of information across continents through the social media and the plethora of questionable alternative theories about the origin and spread of the virus. The lack of uniformity in guidelines might be one of the reasons for growing misinformation in the case of COVID-19. The current disparities in social distancing rules evoke parallels with global controversies over stem cell research and GM crops, where there is no uniform policy/regulations and agreement on scientific evidence. These two cases suggest that variations in science policy across different jurisdictions often present significant challenges to the public communication of science, including distrust in expert advice and the validity of scientific knowledge. In the case of the ongoing COIVID-19 pandemic, efforts to harmonize social distancing rules will be beneficial and can help minimize confusion among the public.