A new scientific paper has quantified the risk of Covid-19 infection at parkrun events as small when virus prevalence is low.
The report by Queen Mary University London and commissioned by Parkrun UK was prepared ahead of the planned return of the popular weekly 5km events on June 5.
Scientists used computer simulations to calculate the risk of transmitting Covid at an average 263-person parkrun event with prevalence as it was in March in the UK.
They found that only 30% of events would have had an infected person present. The modelling also presented worst-reasonable-case estimates for number and duration of human contacts, which resulted in only 0.015% of runners potentially acquiring a COVID-19 infection.
With the prevalence already lower than the rates used in the simulations - and shrinking - it is good news for running race organisers as UK continues to open up. Races have been allowed under government Covid restrictions since March 29, although not all the usual events have returned.
Leading the study was Professor Clive Beggs, who is an expert in the transmission and control of infectious disease, and an advisor to the Department of Health and Social Care, said: ‘Our analysis was undertaken using COVID-19 prevalence levels for March 2021, and the results revealed that parkrun events are likely to be very safe. This finding appears to be supported by the evidence from the various road races that have been held around the world during the pandemic, which have been characterised by a noticeable lack of infectious outbreaks. Based on this, it would seem to me that running events are probably already safe in the UK, and getting safer every day as prevalence falls and the vaccine rollout continues."
The research found that, contrary to popular opinion, transmission was less likely to happen on the start line of events than after the "gun" goes. This was possibly due to the significantly lower breathing rate of participants prior to the event compared to when running, alongside the relatively short time period participants are gathered together.
Over the 10,000 simulations of the model run by the scientists, Professor Beggs concluded that, for the 2.6 million parkrun participants simulated, only one infection would occur on the start line.
According to Parkrun UK, "This finding suggests that measures such as wave or staggered starts are unnecessary, especially when mitigations that minimise the amount of time participants are gathered together are introduced (one of the measures adopted by parkrun in their operational COVID-19 Framework)."
The paper also called into question a previous high-profile wind tunnel study which demonstrated that particles of the virus could be spread behind runners, potentially posing a significant risk of infection to those running directly behind.
Professor Beggs said the pre-print study did not simulate real-life conditions and did not take into account major factors such as the average breeze or cross winds, or the turbulence created by the changing position of runners, and the fact that runners are not static and change direction frequently.
Nick Pearson, chief executive officer at parkrun, welcomed the news as senior parkrun events prepare to return for the first time since March 2020. He said: "I believe the implications of this report are huge for how we view the risks associated with running events and outdoor sport in general. The chances of any infection at all taking place at organised, risk assessed, outdoor events are in fact minimal, even with up to a few thousand participants. We must use data and evidence to inform decision making, and understand that a growing body of evidence does now exist around outdoor sports events such as parkrun, which clearly demonstrates that these events are safe.
"The benefits, particularly now, of getting active, together, far outweigh the close-to-zero risk of virus transmission in outdoor settings. As we look toward the summer, it is vital that we do everything we can to welcome back parkrun events, and get the nation back on its feet, positively impacting the health and happiness of ourselves, our friends, our family, and those around us."
See also: parkrun press release.