Dr. Tom Frieden is the former director of the US Centers for Disease Control and Prevention, and former commissioner of the New York City Health Department. He is currently president and CEO of Resolve to Save Lives, a global non-profit initiative funded by Bloomberg Philanthropies, the Chan Zuckerberg Initiative, and the Bill and Melinda Gates Foundation, and part of the global non-profit Vital Strategies. Resolve to Save Lives works with countries to prevent 100 million deaths and to make the world safer from epidemics. Dr. Frieden is also senior fellow for Global Health at the Council on Foreign Relations. The views expressed in this commentary are solely those of the author.

(CNN) The novel coronavirus is an unprecedented threat. We don't know how bad it will be or for how long it will spread, but we do know that it has already infected more than 118,000 people around the world -- and probably many times that number, killed more than 4,000 people and caused serious global economic damage. We need to adapt our responses to different countries and different parts of the same country in order to limit damage. Using data well is essential to an effective response.

A business that markets a product that no one buys stops making it. If lots of people buy, you make more. Government doesn't have sales figures to go by; public decisions have to be based on other data.

We lack crucial information about the new virus. Here are three areas where we need more data (additional important knowledge gaps here ):

How is the virus spreading? How much do asymptomatic cases spread disease? Are contaminated surfaces important sources of spread?

How deadly is the virus? Reported fatality rates likely overestimate death rates because there are many undiagnosed cases.

What works to limit spread? For example, since children don't appear to get ill, even if infected, they may not be important sources of infection -- so school closures may have limited value.

We learn more every day. We will be able to reduce infections, save lives, and limit damage to society if we rapidly collect, analyze and use data.