Flu as deadly as feared coronavirus

Given what we now know about how easily the new coronavirus spreads, it’s only a matter of time before it starts circulating here in Arizona.

That means state and county health staff and our elected officials will be making decisions about what kinds of public health measures to take when it gets here.

We urge them to exercise two kinds of caution:

❚ Use public health interventions that are reasonable and necessary;

❚ Avoid taking actions that will do more community harm than good.

There’s a balance to be struck in public health. Every decision needs to weigh the costs versus benefits.

Let’s start with what we know. The new coronavirus, which causes COVID-19, seems scary. It’s highly communicable, but it’s probably not as lethal as the news might lead you to believe.

Nearly every flu season, Arizona reports fewer than 20,000 cases of influenza. But the actual number of persons infected is much higher, with 5-20% of the population being infected per season.

The reason? Most people with the flu don’t seek health care. Many who seek care don’t get tested. Lots of people have mild or even no symptoms yet may still spread it to others. We probably find out about only 1 case out of 50.

The same thing is almost certainly happening with this new coronavirus. Mild infection is common. Completely asymptomatic infection has been documented, including transmission of the virus from someone who had no symptoms.

Few people in the mild category are likely seeking care or testing. Even if they seek it, they might not get it. It’s reasonable to assume that something like the 1-in-50 rule is happening right now with this novel coronavirus. That means two things:

First, this virus is more contagious than the reported number of cases would indicate. That’s not good, because most of the actions now being taken to try to prevent spread are likely to eventually fail and it’ll become a global pandemic.

It also means that it’s less lethal than current reports imply. The cases we know about are the sickest ones. What looks like a 2% mortality rate (when you multiply by ~50 times the number of people infected) drops to a 0.04% mortality rate. That puts it right in the range of influenza, which kills approximately 20,000 in the U.S. in an average year.

We believe that we should handle the illness like we do influenza when the virus that causes COVID-19 begins circulating here.

During the 2009 flu pandemic, the guidance from the CDC was to close schools when a student was diagnosed with the new virus. Within a few days, there were three schools closed in Maricopa County, and the number of pending cases made it obvious that the virus was Valleywide. It was spreading, well, like influenza.

It made no sense to close schools based upon where testing happened to have been done when it was almost certainly in many schools. The choice became either close every school, or none.

If we had made the decision to close Valley schools out of an abundance of caution, we would have closed all schools. “Out of an abundance of caution” is public health speak for this may be more than necessary, but because we don’t know for sure, we’re going to take extra precautions.

We decided to err on a different side of caution. Arizona and Maricopa County were among the first jurisdictions in the country to push back against the

CDC recommendations to close schools with an H1N1 case, and we reopened all our schools during the first week of the pandemic. We decided that the economic and social disruption caused by closing schools would do more harm than good. That proved to be the right choice.

When the virus arrives, it will surely be seizing headlines. Even so, some local jurisdictions will likely take the initiative and ease up on control-measures sooner than the CDC is willing to. They’ll push back against the federal and maybe even state guidance in order to protect their communities against unnecessary economic and social damage.

Sometimes the control measures can do more harm than the disease you’re trying to prevent.

We urge the public health system and our elected officials to carefully consider community disruptions before they implement control measures out of an abundance of caution.

Bob England, MD is former director of the Maricopa County Department of Public Health and serves as the interim drector of the Pima County Health Department. Will Humble is former director of the Arizona Department of Health Services and serves as executive director of the Arizona Public Health Association. Reach them at bob.england@ pima.gov and willhumble@azpha.org.