This is the latest in a series of discussions around the novel coronavirus. Last time we looked at risk factors linked to the as built environment, leading into a discussion about whether shops should re-open. This time the topic is a fresh look at social distancing.
READ MORE: Coronavirus: Why it’s too early to open shops
We need to remind ourselves that social – or physical -distancing works. A new World Health Organization study, published in the medical journal The Lancet in June 2020, concludes that separation and keeping distance is the most effective measure, followed by handwashing and hand sanitization.
Social distancing distances vary globally, between 1 and 2 metres. As we’ve covered before, 2 metres makes more sense given the potential distance that droplets projected from a sneeze can travel. At 1 metre, the chance of becoming infected by someone with COVID-19 is 13 percent; at 2 metres, this drops to 3 percent. This is outlined in an metanalysis conducted by a research team led by Chu, which is also published in The Lancet. Moreover, beyond 2 metres the infection transmission rates drops by a further 50 percent.
The following video expands on some of these issues:
But there are other factors that affect the distancing concept. One is time. No matter what the distance, the longer you spend in close contact with an infected person, the bigger the risk. This is fairly logically; although the risks emerge more greatly after a three minute period.
It also depends on what an infected person is doing – for example sneezing over a shorter period of time carries a bigger risk compared with someone who is talking for a longer period of time under conditions, where the same distance is being maintained.
There’s been considerable debate about when social distancing measures should have been introduced and what the impact of any delay was. New research from the University of Austin finds that each COVID-19 outbreak lasts several days longer for each day of delay in implementing social distancing.
The researchers looked at 58 cities for their analysis. This showed that implementing social distancing measures late enables the SARS-CoV-2 virus to spread further compared with cities that acted more promptly.
The overall epidemiological assessment shows that every day a city delayed implementing social distancing measures, following the appearance of a first case added, 2.4 days, on average, to the length of an outbreak.
This also carries risks should a ‘second wave’ occur. The research infers that waiting a week once early signs of resurgence appear, could add 17 further days of social distancing and other supporting measures, like regular handwashing, in order to slow the spread of the pandemic.
A second wave is possible. A major problem with relaxing restrictions too quickly is the limited evidence on how this will affect transmission of the virus. With the easing of lockdowns, if measures backfire and doubles the infection rate, a second wave can be expected. In contrast, if the infection rate balances the recovery rate, the new infections stay approximately constant. Or if infection rates fall, this could push out the possibility of a second wave considerably.
Social distancing also helps with track and trace schemes, and there is a relationship between the two. Research relating to South Korea found that public disclosure about contacts, connected with potential symptoms, provided important community information enabling people to take physical distancing measures. Such measures, based on computer modelling, could reduce a projected community death down by 20 percent.
Without public disclosure, the death rates rise. While there are debates over privacy with contact racing apps, secrecy in the time of the viral pandemic costs.
