Coronavirus forecasts are grim, and ‘it’s going to get worse’

A rash of alarming forecasts for the coronavirus pandemic emerged Wednesday. The viral outbreak officially became a pandemic in the eyes of the World Health Organization, which cited the alarming spread of the disease called covid-19 and the slow response of many nations to try to contain it. German Chancellor Angela Merkel said 70% of her citizens could become infected. On Capitol Hill, at a tense House of Representatives hearing, the nation’s leading doctors did nothing to dispel the atmosphere of gloom and anxiety.

"Bottom line, it's going to get worse," Anthony Fauci, the long-standing director of the National Institute of Allergy and Infectious Disease, testified.

How much worse is the pressing question for a nervous American public and its fractious leadership. What happens in the weeks to come likely depends on how aggressively the U.S. tries to contain the coronavirus even at the cost of massive social and economic disruptions - and also on the virus itself, a new pathogen that is still revealing its true nature.

Experts have produced forecasts of likely infections, serious illnesses and death tolls, based on what is known about the coronavirus and how past epidemics have played out, and they suggest that the U.S. - which has surpassed 1,000 confirmed covid-19 infections and 30 deaths - must prepare for a potentially historic pandemic.

Most coronavirus patients have mild or moderate illnesses and recover without need for hospitalization. The people at elevated risk of serious illness are "older adults," in the phrase of the Centers for Disease Control and Prevention, and anyone with an underlying chronic illness such as heart disease, lung disease or diabetes. Data from China showed that the risk increased for people over the age of 60 and was greatest for people over 80 who had an underlying chronic illness.

How this will play out in the U.S. may not match what happened in China, where the initial outbreak in late December and early January quickly overloaded the health system and led to a high fatality rate.

Some of the projections for covid-19 spread in the U.S. have been grave. A forecast produced last month by University of Nebraska Medical Center professor James Lawler on behalf of the American Hospital Association, for example, put the potential death toll in the hundreds of thousands if efforts to mitigate the epidemic failed.

Another forecast, developed by former CDC director Tom Frieden at the nonprofit organization Resolve to Save Lives, found that deaths in the U.S. could range widely, depending on what percentage of the population gets infected and how lethal the disease proves to be. Frieden, who oversaw the 2009 H1N1 influenza pandemic, the 2014 Ebola epidemic and the 2016 Zika epidemic, says that in a worst-case scenario, but one that is not implausible, half the U.S. population would get infected and more than 1 million people would die.

His team put together a simple table that looks at various scenarios using case fatality ratios ranging from 0.1, similar to seasonal flu, to 0.5, a moderately severe pandemic, and 1, a severe one. The infection rate ranged from 0.1% of the population to 50%. That put the range of deaths from 327 (best case) to 1,635,000 (worst case).

U.S. officials have said they are working with 50 academic modeling groups. But so far, no projections of the outbreak's trajectory have been publicly released by the CDC or the White House coronavirus task force. Still, Frieden said, "anyone who says that they know where this is going with confidence doesn't know enough about it," he said.

Communities should undertake social distancing measures and assume the virus is there, unless proved otherwise, he said. The worst-case scenario can be prevented through common-sense measures, he said, such as holding sporting events in front of empty seats. "Stopping fans from coming into Madison Square Garden is a no-brainer," he said, referring to the Big East men's basketball tournament scheduled to begin Wednesday evening and run through Saturday.

In recent interviews, epidemiologists have suggested that the coronavirus outbreak could be on the same general scale as the 1957 influenza pandemic. They do not believe it would be as catastrophic as the Spanish Flu of 1918, which killed an estimated 675,000 Americans and 50 million people worldwide in an era when the population was much lower.

The case fatality rate for covid-19 - higher than 3% so far globally, according to the WHO - is an evolving number that depends on multiple factors, including access to robust health care. The actual lethality of the virus is hard to determine because many people have mild or no symptoms and never get formally diagnosed. Some deaths from covid-19 may also have been missed, possibly mistaken as flu-related.

In his testimony, Fauci said a plausible fatality rate could be 1%. That, he said, is 10 times as lethal as seasonal influenza. He was clear: This is more dangerous than the flu.

"We must be much more serious as a country about what we might expect," Fauci said. Even places that have little or no known community transmission at the moment need to take action to try to limit infections, he said: "A couple of cases today are going to be many, many cases tomorrow."

Knowing how fast and wide the disease can and will spread requires information that the U.S. lacks, largely because the CDC struggled to produce and distribute reliable coronavirus test kits.

"The problem with forecasting is you have to know where you are before you know where you're going and because of the problems with testing we're only starting to know where we are," said Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security. "That's why there's not that much forecasting available yet."

WHO officials on Wednesday noted that several countries, including South Korea and China, have demonstrated that the virus's outbreak can be suppressed and controlled through old-school public health measures of aggressive contact tracing, quarantines and isolation of the sick, social distancing and mobilization of the public to sanitize and prevent transmission.

"Some countries are struggling with a lack of capacity. Some countries are struggling with a lack of resources. Some countries are struggling with a lack of resolve," said Tedros Adhanom Ghebreyesus, the WHO's director-general.

Michael Ryan, WHO director for health emergencies, said, "There's a real chance to blunt the curve, a real chance to bend the curve … Why would you not use the opportunity?"

Forecasts have been wrong in the past. Early estimates on the fatality rate for H1N1, a pandemic influenza in 2009, were much higher than the roughly 0.01% to 0.03% it turned out to be. With covid-19, the fatality rate is likely in the 0.5% to 1.5% range outside Wuhan, China, according to an Imperial College report this week.

China has apparently managed to get some control over the epidemic, reporting no deaths outside of Hubei province on most days during the past week. China's success came after an intense, communitywide response that included extreme measures of isolation and social distancing.

The epicenter of this pandemic is now Europe - to the point that CDC Director Robert Redfield told Congress, "Europe is the new China."

Any virus is far too small to be seen, and a single sneeze can produce hundreds of thousands of infectious particles. A virus like this one can potentially remain infectious for a matter of hours on a surface, such as a door handle or an ATM touch screen.

What makes this virus especially tricky to contain is that it apparently can be spread by people who don't know they're infected and have no symptoms yet. That wasn't the case with severe acute respiratory syndrome, a similar coronavirus that began spreading in China in 2002 and was contained the next year. Because SARS patients only shook the virus after they became very sick - nearly 1 in 10 died of the disease - the health care systems were able to identify and isolate patients and keep the total number of cases below 10,000 globally. This new virus already has sickened well over 100,000 people, and the number of infections - including people with mild illnesses or who did not develop symptoms - is much higher.

That virus (officially SARS-CoV-2) does not spread as efficiently as influenza.

The new coronavirus has an estimated reproduction rate - meaning the number of infections generated by each infected person - somewhere between 2 and 3. For the epidemic to end, that reproduction rate ("R-naught," in medical lingo) has to fall below 1. Influenza's rate is about 1.5.

But the R-naught isn't an intrinsic feature of the virus, said Gary Whittaker, an infectious-disease expert at Cornell University. Contagiousness is a slippery metric because so much depends on the social and physical environment in which the virus is spreading. In crowded cities it spreads more easily than in wide-open areas, and the R-naught can be lowered through a variety of interventions, including, eventually, a vaccine.

More important is the metric known as the serial interval. That refers to the amount of time it takes on average for one infection to lead to another infection in the chain of transmission. That's about four days for the new coronavirus. SARS was about seven days. Influenza is only a couple of days. The flu spreads so quickly that it's essentially impossible to contain through social distancing. But the slower spread of the coronavirus makes social distancing the right strategy now, Whittaker said.

"The social distancing will bring the R-naught down and ideally will bring it below 1," he told The Washington Post on Wednesday.

He added: “We don’t have anything else we can do. There’s no vaccine. Theres’s no drugs. We’re fortunate that the virus is in the middle ground, between influenza and SARS, in terms of transmissibility. The social distancing can be effective if it’s done correctly.”