Mathematicians say preventative measures could have huge impact on coronavirus spread

With the novel coronavirus spreading exponentially in the United States, “flattening the curve” could seem challenging. According to mathematicians, simple preventative measures may be more effective than you think.

“Over the past six weeks, the number of recorded cases of COVID-19 outside mainland China has increased approximately 15% per day, which means doubling every five days,” mathematician Grant Sanderson told ABC News.

Sanderson runs a program called 3Blue1Brown, which teaches complex math lessons using visual aids. His YouTube videos sometimes use real-world scenarios as examples, and his video explaining the exponential spread of COVID-19 just surpassed 3 million views.

Sanderson said the virus’ rate of spread has been consistent across several different countries, regardless of when the country’s outbreak began. At its current rate of exponential growth, the virus could spread to over a million people in the U.S. by the start of May, according to Sanderson.

That current rate, however, doesn’t account for human intervention, according to Sanderson and other experts in the field.

“There’s a caveat there,” said Dr. Mac Hyman, a professor in mathematics at Tulane University. “If no one changes their behavior in the next month, then it could result in a million cases. But if people change the way that they interact to both protect themselves from being infected and infecting others – then it could actually decrease.”

Dr. Maimuna Majumder, a computational epidemiologist Boston Children’s Hospital Computational Health Informatics Program, emphasized Hyman’s point: although the math could seem scary, there’s a lot more to consider.

“I am very wary of simplistic projections about the ongoing outbreak based solely off of its current growth patterns,” Majumder told ABC News.

She believes America's current efforts to stall the spread of COVID-19 could actually stop the virus from spreading exponentially.

"The fact that interventions can reduce the growth rate to the point that it is no longer exponential can’t be over-emphasized," she said.

Simple acts like washing your hands and self-isolating “can have monumental implications for the number of cases in a few months’ time,” said Sanderson.

According to Sanderson, if the rate of spread dropped from 15% to 5% per day thanks to society’s collective efforts, then the U.S. could be looking at less than 15,000 cases by the start of May – rather than over a million.

“So, if people are sufficiently worried, then there's a lot less to worry about,” said Sanderson. “But if no one is worried, that's when you should worry.”

There are currently over 3,700 confirmed COVID-19 cases in the U.S., according to Johns Hopkins University. But there's another problem when estimating how quickly the virus is spreading: no one knows exactly how many COVID-19 cases are prevalent in the U.S., according to Dr. John Brownstein, chief innovation officer at Boston Children's Hospital.

“We need to be careful about our case count – there are clearly more cases out there,” said Brownstein, who noted that “confirmed cases” do not accurately reflect the number of cases that are in the United States but rather only reflect the number of patients that have been tested and are positive for COVID-19.

Both private and government organizations have taken unprecedented steps in slowing the spread of the virus. The NBA, NHL and MLB have suspended their seasons to avoid close quarters contact among fans and players. Local governments including in New York and Los Angeles announced over the weekend they were shuttering businesses such as bars and entertainment venues.