Faculty soccer crowds may influence COVID-19 unfold
The observed spike in COVID-19 cases, which coincides with the reopening of college campuses in the United States, has drawn intense scientific attention. A paper by researchers at Washington State University recently published on the medRxiv * preprint server in September 2020 reports that this threat is directly related to the conduct of personal sporting events at these locations.
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University sports events – hold or not hold?
The current situation regarding COVID-19 has inevitably sparked a debate about the role of college reopening, with an emphasis on whether in-person tuition is safe or necessary during this time. An integral part of such controversy concerns the sporting events organized by these colleges, particularly college football.
Fall marks the start of the regular college football season, which means huge profits – tens of millions of dollars – for the colleges hosting the games. These games attract a large number of spectators and the preparation involves many players who are trained daily many months in advance.
As of now, many of the leading college football leagues, including the Ivy League and Big Ten, have canceled their seasons or at least delayed their start. However, these are economically painful decisions and many institutions will try to organize at least a shortened version of their football season.
Schematic representation of a model of COVID-19 transmission due to personal sporting events. The campus population is shown in the blue box, while visitors are shown in the gray box. The campus population can assume four health states – vulnerable (S), exposed (E), infectious (I), asymptomatic (A), or recovered (R), while visitors are presented as two states: vulnerable (VS) or infectious (VI)) . Solid arrows indicate transition terms, while dashed arrows indicate possible transmission paths. The relevant parameters for each are also displayed.
Safe sporting events?
A major aspect of such decisions is the safety of such events, including the ability to limit the transmission of Severe Coronavirus 2 (SARS-CoV-2) with Acute Respiratory Syndrome between players during the game and to organize spectators so that social distancing is observed. and how to comply with safety standards for team players, coaches and other staff members during routine exercises and while traveling to and from the various remote venues for the Games.
Such decisions require the use of a great deal of knowledge “ranging from the epidemiology of COVID-19 to the built environment of locker rooms,” organizers said. The current study is therefore limited to the sole question of whether and how the abrupt and temporary convergence of large numbers of visitors to a college for the purpose of such a sporting event along with other related activities such as going to bars and restaurants and eating meals around a parked vehicle and other forms of interaction with local student and urban communities.
Using a mathematical model to understand how such regular mixing of outsiders with local residents and students on a large scale would affect COVID-19-related health risk, the researchers first examined two base scenarios. In one case, the campus had a transmission number just below R0, with a median of ~ 216 cases among students on campus. In the other, R0 was just over 1 and the number of local cases was> 1,100 cases. The first was a small outbreak while the other was an uncontrolled situation.
Campus R0 <1
When the campus had a small outbreak, the median number of cases was 216 when there was no personal sporting event. When visitors from another community with a low case prevalence were included in the model, it increased to a median of 330 cases, an increase of 52%, even if the interaction rate between students and visitors was assumed to be low. With strong mixing, the increase in cases is over 100% with a median of 437 cases.
When the visitors were from a high prevalence population, the mean number of cases in the low and high mix simulations rose to well over 1,100 and ~ 2,000, respectively. This corresponds to an increase in cases of 452% and 822%, respectively.
Campus R0> 1
The second control scenario considered by the researchers concerns a campus where the R0 is still above 1, which indicates that an uncontrolled outbreak is occurring. Here the incidence of base cases is ~ 1,100, but with an influx of visitors from an environment with low prevalence and limited interactions, this increases by 25% to a median of 1,400 cases.
With unrestricted mixing between visitors and students, the number of cases increases by 43% to a median of 1596 cases.
If the visitors are from a community with high prevalence, the increase in low and high interaction scenarios results in medians of ~ 3,100 and ~ 4,500 cases, which are an increase of 177% and + 304%, respectively.
The researchers also found that the first scenario with an R0 less than 1 but with sporting event goers from a high prevalence area and with free interactions between local students and visitors likely resulted in an 11-fold increase in the number of COVID-19- Cases compared to the same campus with no personal sporting activity.
In four different simulations that focus on the occurrence of sporting events during a period not yet including COVID-19, it is found that the number of cases on campus has seen a significant increase.
The proportion of the increase, although not the absolute case load, is particularly noteworthy at locations where the R0 had fallen below 1. This suggests that regular external exposure to infectious cases either triggered a new outbreak or disrupted the natural extinction of the ongoing outbreak.
When the outbreak was not yet controlled, the number of already large cases soared to much higher levels, which could overwhelm the local health system capacity. This could mean that more people are succumbing to the disease due to a lack of local medical care facilities as the need increases sharply.
While visitors from areas with low and high prevalence affected the mean number of cases differently, 10 infectious visitors out of a total of 10,000 are producing outbreaks of considerable size.
The study concludes that “personal sporting events pose a significant health risk to the campus community” and that “risk-free personal sporting events are not necessarily possible for the foreseeable future”.
It is important to note that all of these simulations only dealt with cases resulting from interactions between visitors and students on campus, ignoring transmission between players, within the community, and between visitors. Even such optimistic projections suggest that hundreds of new cases can arise from personal sporting events.
Given numerous uncertainties about the disease and its seasonal dynamics, the researchers say, “From a public health perspective, it appears advisable to cancel personal sports events on college campuses for the duration of the pandemic, or at least until a widely available and effective vaccine exists . “
* Important NOTE
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information.