Stop a US coronavirus outbreak before it starts


The Wuhan coronavirus continues to spread at an alarming rate. More than 20,000 cases have been confirmed in China, with another 23,000 suspected. Many in China aren’t even being tested due to a shortage of diagnostic supplies. The true number infected is likely much higher than reported. The virus has turned up in 28 other countries, including the U.S. A pandemic seems inevitable.

The U.S. government has moved quickly to try to delay the spread throughout America. As of Feb. 2, most foreign nationals who have traveled in China in the preceding 14 days aren’t able to enter the country. Americans and their immediate family who recently traveled to China are subject to medical screening and quarantine.

These travel measures may stall a U.S. outbreak. But they’ll become less effective as more cases appear outside China. It’s clear that China waited several weeks to tell the world about the outbreak. Meanwhile, roughly 250,000 Chinese nationals traveled to the U.S. People with only mild symptoms can spread the virus to close contacts.

So far the 11 known U.S. cases are recent travelers to Wuhan and their household contacts. But it’s highly probable that dozens of other cases have gone undetected. The first sign of an outbreak will be a cluster of patients in one community stricken with unexplained pneumonia. The priority should be identifying this community transmission early, so that public-health authorities can intervene and prevent spread throughout the U.S. That will require several steps.

First, doctors must be on high alert. The Centers for Disease Control and Prevention should expand its guidance to doctors: Be suspicious of anyone with unexplained pneumonia who tests negative for common viruses, even if the patient has no connection to China.

An expanded sentinel surveillance system—detailed data collected from a network of high-risk locations—could help spot unusual clusters of illness that might be the beginning of an outbreak. If only 10% to 20% of people develop serious symptoms, then for every person diagnosed there may be eight or nine who elude detection.

Second, these expanded criteria should translate into broader screening. It’s crucial to identify cases of secondary spread, in which someone catches the virus from another person who hasn’t recently been to China.

CDC currently recommends testing only those with a clear and known risk factor, such as travel to China or close contact with an infected or exposed person. The patient must also be showing symptoms, such as fever and shortness of breath. This strategy will miss illnesses coming from a potential outbreak in which the index case—the person who traveled to China, for example—is two or three steps removed from the people who show up at the hospital with pneumonia. It’s time to start testing more people, even if they haven’t visited China or been in contact with someone infected.

Containing the virus will also require more labs that can perform diagnostic tests. Right now only the CDC is running tests, and the agency is showing signs of strain. It’s taking CDC about 36 hours to turn around results, even with strict limitations on who should be tested. Expanded screening will further stretch the agency.

CDC is planning to distribute test kits as soon as this week that would allow designated public-health labs to run the test. Private test developers need clearance from the Food and Drug Administration to distribute or use tests. But that will take some time. Developers need access to samples to be sure their tests are reliable, and companies have to submit paperwork for FDA review.

Many major medical centers in the U.S. already have the capacity to run tests. The test is based on polymerase chain reaction, or PCR, that screens for bits of the coronavirus RNA. Most major hospitals have sophisticated labs that can conduct these tests. This type of test is relatively cheap, technically straightforward and routinely used by doctors. CDC can help by giving hospitals more access to positive controls and reference material.

If the virus is silently spreading among people without a connection to China, and if only a fraction of the ill develop pneumonia, then it might take dozens of infections to notice an outbreak. By that time, an epidemic will be hard to prevent.

Scott Gottlieb is a resident fellow at the American Enterprise Institute.

Be the first to comment

Leave a Reply