Novel coronavirus, also known as Covid-19, has killed more than 1,300 people and infected upwards of 47,000, according to the World Health Organization.
Those numbers were accurate as of Feb. 13 and continue to grow exponentially. The novel virus originated in Wuhan, China, but in the space of several weeks it had spread to the U.S., Europe, Canada, Australia and other parts of Asia.
Eric Rubin MD, PhD, editor-in-chief of the New England Journal of Medicine, and Lindsey Baden, MD, deputy editor of the journal, sat down with NEJM Executive Managing Editor Stephen Morrissey, PhD, for a chat about the coronavirus outbreak and what it means for public health.
According to them, this is what every physician should know about the infection.
Coronavirus no. 3
This isn’t the world’s first coronavirus, Rubin said—far from it. There have been a number of human infections with coronavirus for a long time, but until the early 2000s the only virus we knew about caused a mild upper respiratory tract infection. That changed when SARS (Severe Acute Respiratory Syndrome) surfaced in 2002 and, as its name suggests, turned up the dial on severity.
MERS (Middle East Respiratory Syndrome) coronavirus emerged in 2012 in Saudi Arabia, triggering an even more severe, potentially fatal infection that first spread from camels to humans. SARS was eventually controlled and eliminated—largely through quarantine—and Rubin said that as a seasonal virus, it also may have “simply disappeared.” MERS remains present at low levels but doesn’t transmit very efficiently, rendering its global risk minimal.
“So this is our third coronavirus, and, like the other two, it appears to be primarily an animal virus which has been transmitted to people,” Rubin said. “This one, like the others, likely originated in bats but may have been transmitted through an intermediate animal vector.”
Baden said it’s unclear how this specific brand of coronavirus originated, but it’s possible it spread via “wet markets” in China, where vendors sell a selection of produce, fish and fresh meats in an open-air setting. Once the coronavirus made the species jump, he said, it was easy for it to make its way from human to human.
At the time of their conversation, Baden said current coronavirus estimates hovered somewhere around 30,000 cases globally, with most reported in China. Physicians are increasingly able to diagnose the respiratory illness more rapidly, but because the infection is spreading so quickly, it’s hard to quantify the severity of illness.
“Estimates are that 15% of patients may have severe illness, [from] what we hear from public health authorities,” Baden said. “Which of course raises concern about how significant will the illness really be?”
Doctors haven’t pinned down a particular spectrum of clinical presentation for this coronavirus, but the primary spectrum seems to include respiratory transmission and respiratory infection that leads to pneumonic or pulmonary infection. More severe cases have been linked to more viral pneumonia with bilateral lung infiltrates and respiratory compromise, but that’s a minority of patients.
Rubin said it’s impossible to know how much minimally symptomatic disease we’re missing—but it’s important that we try. He said that understanding how bad the disease is and how it transmits from person to person is a key question “that we can only answer if we’re aware of how many minimally symptomatic cases there are.”
“We’ve seen an increasing number of reports of people who have detectable viral RNA despite the fact that they don’t have a flu-like illness,” he said. “That suggests that the reservoir of disease might be quite large.”
Right now, Baden said, treatment for coronavirus predominantly includes supportive care and complication management. No direct antiviral therapies that target the specific virus have been established, but some other drugs—including lopinavir/ritonavir and remdesivir—are being studied in the context of coronaviruses like MERS.
“I think it’s very important, as we learned from the Ebola outbreak and other outbreaks, the importance of doing high-quality studies rapidly to determine which of these or other agents are effective,” Baden said. “So we can scale up quickly to benefit our patients. But we need to sort out which of these agents work given the complexity of the illness we’re caring for.”
It’s a tall order, he said, but physicians need to find a way to both advance knowledge and study of the coronavirus while simultaneously preventing spread and caring for patients who are already infected. Understanding the transmission dynamics of coronavirus, which right now we’re grappling to define, will also be key to finding prevention and treatment strategies.
Quarantine was a major control tool for both SARS and MERS, but Rubin noted both of those diseases had certain characteristics that allowed scientists to limit their spread. SARS and MERS were also more symptomatic than this coronavirus seems to be, meaning it was easier to identify individuals for quarantine at that time.
“Public health authorities have been put in a very difficult situation,” Rubin said. “They have to act now, and they have to act on very limited information.And they’re making the choices, in this case how tight quarantine will be, based on guesses. These are essentially experiments. And it’s extremely important for us to understand what works and what doesn’t going forward. And to test whether or not these interventions are the best methods to control disease.”