UAA publishes virus infection model
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Analysis projects potential COVID-19 infection trends in Alaska, based on different policies for slowing the infection spread
A research team in the University of Alaska Anchorage has published the results of modeling of the potential spread of COVID-19 infections in Alaska. The team conducted the study in response to a request from the Municipality of Anchorage - the municipality is seeking data that can enable effective policies to deal with the pandemic.
“Quality data and quality data analysis allow us to project the course of the of the outbreak, so we can put forward appropriate policy and deploy resources in the most effective manner,” said Anchorage Mayor Ethan Berkowitz. “The UAA modeling team gathered data, synthesized best practice modeling and provided critical analysis. We will continue to work with them to inform decisions moving forward, and are appreciative that we can share this information and methodology with the governor and the state team, so that municipal and state actions are coordinated in the time ahead.”
Publicly available modelUsing a publicly available model for projecting the infection spread, based on available data relating to the properties of the virus, and using current data regarding infections in Alaska, the team was able to construct future scenarios, based on different policies for limiting the rate of spread of infections.
“These mathematical models - along with the experience of other cities and countries around the world - show us how quickly this virus can spread,” said research team leader Dr. Tom Hennessy. “What we’re seeing is that if we do too little, we will overwhelm our hospitals and break our healthcare system. To save lives, we need to do as much as we can, as soon as we can, to prevent the spread of COVID-19 in Alaska.”
Essentially, infections from a virus such as COVID-19 typically increase exponentially, as one infection causes several other people to become infected. Left unchecked, this rapid and escalating rise in infections can overwhelm the capacity of the health care system to deal with serious, potentially fatal cases. If the rate of infection from one person to others can be reduced, the rate of infection increase can be slowed, thus lowering the number of serious cases that need to be dealt with at any specific time.
Four scenariosThe UAA team modeled the potential spread of infections, starting with data for reported COVID-19 cases in Anchorage and the Matanuska-Susitna Borough through March 23. And the team modeled the impact of four different approaches to dealing with the spread of the virus: no action; the use of social distancing; the imposition of a shelter in place order; and the imposition of a lockdown order.
Social distancing would involve the possibility of population-wide testing of the virus, together with the quarantining of infected people. There would be public advocacy around social distancing behaviors, together with some school closures and bans on large gatherings. There would also be voluntary shelter arrangements for people at high risk from the effects of infection.
Shelter in place goes further, by mandating people to stay at home, except for certain activities such as critical employment, obtaining supplies, and exercising. Non-essential businesses would be closed. And violators of the orders could be fined.
In a lockdown, everyone would be subject to home quarantine, with non-essential travel banned, and with the state distributing food.
Model predictionsThe modeling predicted that, under the no action scenario, new COVID-19 cases in the Anchorage/Matanuska-Susitna area would overwhelm the region’s healthcare capacity within weeks. There could be up to 7,400 patients requiring hospital care, in a region with just over 982 hospital beds, the modeling determined.
Social distancing would significantly reduce the number of hospitalizations required and would provide three to four weeks of preparation from March 25 for the influx of hospital patients. After that, current hospital capacity would be overwhelmed.
Currently Anchorage has policies similar to those assumed for the shelter in place scenario. Modeling of this scenario indicates that there would be fewer infection cases so long as the relevant mandates are in place. The infection rate would likely rebound, to far exceed hospital capacity, once the mandates are removed. However, the delay in the infection spike might provide time to increase the capacity of the healthcare system. And it is possible that the impacts of removing the mandates could be mitigated by reducing the restrictions a step at a time, rather than all at once, the researchers suggest.
A lockdown scenario, on the other hand, would maintain hospitalizations at levels within the hospital capacity.
Adapting the model to the whole of Alaska, rather than just the Anchorage/Matanuska-Susitna region, showed similar results for the four scenarios, the researchers reported.
RecommendationsAs a consequence of their findings, the researchers recommended the urgent need for the implementation of some additional virus containment measures, including mandated shelter in place and narrower definitions of what constitutes essential businesses. The closure of non-essential businesses needs to be enforced; non-essential workers should have to work from home; school closures need to be maintained; and non-essential travel to and within Alaska needs to be restricted. The quarantining of travelers entering Alaska needs to be coordinated between the state and local protocols. And there needs to be continued tracing of people who have contacted others who have been infected, with home quarantining of close contacts, the report says.