On Thursday, state officials shared a model they say is helping them predict the possible trajectory of COVID-19 in New Hampshire. According to Gov. Chris Sununu and state epidemiologist Ben Chan, early signs show that the state’s strategies of social distancing and community mitigation are helping to control the spread of COVID-19.
Below are some answers to frequently asked questions about the models the state is using.
Where do these models come from?
Chan says the state has not developed a model of its own. Instead, health officials here have looked at about half a dozen models coming from other institutions, including the University of Washington, Imperial College London, The University of Pennsylvania, and Brown University.
Of these models, the one that has been mostly widely cited nationally is the University of Washington/IHME model. This model uses information based on the trajectory of the virus in places where the virus has already peaked to predict when and how it will peak elsewhere.
How accurate are these models?
It’s hard to say. COVID-19 is a new virus, and we’re learning more about it each day.
The University of Washington model uses data from places that have already seen a peak in infections. Initially, this was limited to Wuhan, China, so the model’s predictions were less accurate. As more places around the globe experience a peak in infections, more data is added to the model, and the more accurate it becomes. Currently, the model is using data from seven communities in China, Italy, and Spain.
One of the earliest models was the Imperial College model. On March 16, that model predicted that without any social distancing measures, the United States could see as many as 2.2 million deaths as a result of the coronavirus. But that model also has projections for how the U.S. might fare with different levels of social distancing, which reflect a lower rate of mortality.
These differences between models may not be a sign of inaccuracies, but rather an indication that social distancing and other measures are effective in slowing the spread of the virus.
So, when will COVID-19 peak in New Hampshire?
In a press conference in Concord Thursday, April 9, Chan said, “based on the models that I have reviewed, and our New Hampshire data, we believe that there’s a high likelihood for a potential peak in New Hampshire sometime within the next several weeks.”
In fact, the IMHE model states we may have already passed one peak. As of Friday, April 10 at 4:00 pm, the model says peak resource use in New Hampshire took place on April 9, with 165 hospital beds and 28 ICU beds needed on that day. It predicts that the peak in deaths will occur six days from now, on April 16, with an average of three deaths per day.
However, those dates have changed several times in the past 24 hours, and will likely continue to change.
Chan stresses that reaching a peak doesn’t necessarily mean the number of cases will go down right away.
“What we might see in New Hampshire, and what we’ve seen many times with different outbreaks, is that there could be a plateau phase where the number of cases isn’t going up, isn’t going down, but it’s plateauing before there’s a decrease, before there’s a backside of the curve,” says Chan.
If social distancing is working, can we begin to relax?
Speaking on NHPR’s The Exchange, Chan said there’s some early evidence that the number of hospitalizations and new infections of COVID-19 in New Hampshire are starting to slow.
“But I want to emphasize that this is still very early data, and it’s possible that these numbers will go up again,” Chan said.
Chan stressed that people in New Hampshire need to stay vigilant.
“So really now is the critical time for people to continue their social distancing measures, staying at home, maintaining a distance of at least six feet from other people, because now is what we believe is the critical time to really try and have the most impact on how this pandemic proceeds," he said.