with Paige Winfield Cunningham

The surge in coronavirus cases driven by the highly contagious delta variant, which has come to dominate in the United States, is bad and getting worse. But just how bad it will get is difficult to determine, epidemiologists and biostatisticians told The Health 202.

The United States is reporting more than 75,000 cases per day, up from a low point of around 11,000 cases a day just six weeks ago. Hospitalizations are up 42 percent over just the past week and deaths have risen by 31 percent.

Modeling the coronavirus is not easy. While forecasts are important for charting possible scenarios and guiding public health policies, they often struggle to predict inflection points, when case rates turn around rapidly.

Our colleagues Ben Guarino and Dan Diamond report that many experts think the current surge will get worse before it gets better.

A model out of Columbia University predicts that the United States will see 140,000 cases a day by the end of August. Modelers at the University of Washington’s Institute for Health Metrics and Evaluation show cases rising through mid-August and leveling off at 300,000 daily cases.

But experts say there are plenty of unknowns, including the role of human behavior.

The United Kingdom, for instance, saw a similar, rapid surge in coronavirus cases driven by the delta variant, only to see the case rate turn on a dime and start to plummet, confounding the expectations of many scientists.

“This isn’t a deterministic physics system like the atmosphere and weather,” Nicholas Reich, a professor of biostatistics at the University of Massachusetts Amherst told The Health 202. “Here we’re dealing with humans who are reacting to front-page news, case counts and travel on the holiday.”

Reich runs the Covid-19 ForecastHub, which receives funding from the Centers for Disease Control and Prevention to compare and merge more than two dozen different models. The ensemble model shows that between 200,000 and 1.2 million new cases will likely be reported by the week ending Aug. 21, averaging between roughly 25,000 and 175,000 new cases per day.

The big range reflects a huge amount of uncertainty in the models.

“It is entirely possible that we continue to see rapid growth over the coming weeks. It's also possible — like the U.K. and the Netherlands have experienced with a ‘delta wave’ in recent weeks — that we might see a rapid turnaround of the current trends,” Reich said.

The delta variant is way, way more contagious and that makes a big difference.

Justin Lessler, a University of North Carolina epidemiology professor who coordinates a separate coronavirus modeling hub that makes longer-term projections, asked modelers to estimate the course of the delta variant based on different assumptions about just how infectious the new variant would prove to be.

The optimistic scenarios assumed the delta variant was 40 percent more transmissible than the alpha variant — a variant also known as B.1.1.7 that was first identified in the U.K. and became dominant in the United States this spring. The pessimistic scenarios assumed that it would be 60 percent more transmissible.

“That pessimistic scenario seems closer,” Lessler said.

And it’s important to remember that the alpha variant was already much more transmissible than the original coronavirus variant that first wreaked havoc across the United States. Lessler estimates that the delta variant is roughly 2½ times more infectious than that original strain. That new calculus will be especially dangerous in regions of the country where vaccinations are low and where there is less immunity from previous outbreaks. 

“It means that somebody who we would have expected to infect around two people over the course of their infection, that same person we’d expect [now] to infect more than five people. The amount of vaccination you need and masking you need to turn the curve and bring things down is that much higher,” Lessler said.

Infectious disease expert Anthony S. Fauci said on Aug. 1 that he does not expect any lockdowns to curb covid-19, despite a surge in cases. (Reuters)
But there’s one point of optimism: The relationship between cases and deaths has shifted dramatically.

Vaccination rates in the United States are highest among the elderly, meaning that many of the most vulnerable Americans are already protected. And while there have been reports of breakthrough infections, those cases tend to be mild. The vaccinations are highly effective in preventing hospitalizations and deaths.

The result: When cases go up, most models take for granted that hospitalizations and deaths won’t increase at anywhere near the same ratio as a year ago.

That was the case in the United Kingdom, which has one of the highest vaccination rates in the world, with 57 percent of its population fully vaccinated. The U.K. saw a massive delta-driven spike in cases but forged ahead with its reopening plans based on the fact that hospitalizations remained much lower. 

“In terms of the number of cases, this new surge in the U.K. was pretty similar in size to the one that they saw in the winter, but it hasn’t translated into deaths at nearly the same rate,” said Stephen Kissler, an immunology and infectious disease research fellow at Harvard's T.H. Chan School of Public Health.

The Washington Post’s coronavirus tracker shows that relationship: 

The U.K. also has seen a rapid downturn in cases, which experts have struggled to explain, as our colleagues Karla Adam and William Booth have reported.

Some scientists posit it was the sunshine from a week-long heat wave or that most children are not in school during summer break. Even the end of the Europe’s championship soccer tournament — and the many festivities that went along with it — could have played a small role and the sudden change of course. But others are hopeful the decline in cases signals a more permanent shift as more of the population is protected by vaccines or prior immunity.

In comparison, the United States has a lower vaccination rate. Just under 50 percent of Americans are fully vaccinated. And the United States is a much larger country, so even as surges end in one part of the country, they often take off somewhere else. The end result, Kissler said, is that if you look at the national average, our surges tend to build and die down more slowly than in the U.K.

There are other factors that could come into play.

The reopening of schools and workplaces could fuel more outbreaks. Meanwhile, the resumption of masking in many indoor spaces and the winding down of summer travel could push trends in the other direction. Vaccine uptake will be one of the biggest factors in shaping the course of this latest surge.

“One of the messages about forecast accuracy is that it’s really hard to predict cases, even just a couple weeks into the future,” said Reich.

But that’s not all bad, he told The Health 202: “I feel like there’s a silver lining behind that. The reason it’s hard to predict cases is because human behavior can change the trajectory really quickly and that means it’s in our own power as a society to change the curve.”

Ahh, oof and ouch

AHH: The FDA is vowing an ‘all hands on deck’ effort to fully approve Pfizer’s coronavirus vaccine. 

“With coronavirus cases surging, the Food and Drug Administration’s top vaccine official said Friday the agency is redeploying staff and adding computer and other technical resources to accelerate an effort to grant the Pfizer coronavirus vaccine full approval as rapidly as possible,” The Post’s Laurie McGinley reports.

Peter Marks, director of the Center for Biologics Evaluation and Research, told The Post that the agency was rolling out an “all hands on deck” strategy to expedite approval of the vaccine. While Marks declined to comment on the timeline for approval, some agency officials have suggested that the FDA could approve the vaccine in a matter of weeks.

The FDA has faced mounting pressure from lawmakers and some public health experts to fully approve the vaccine. Those pushing for an expedited approval say it would make it easier for the government and employers to mandate the vaccine and would combat vaccine hesitancy. The Kaiser Family Foundation found in June that 32 percent of unvaccinated Americans said they would be more likely to get the shot if it were fully approved.

OOF: Florida broke a record for new coronavirus infections.

Florida reported 21,683 new coronavirus cases on Friday, the highest one-day total since the start of the pandemic, according to CDC data.

“The data shows the severity of the surge in Florida, the epicenter of the U.S. outbreak and now responsible for 1 in 5 new infections nationally. The previous peak in Florida had been on Jan. 7, when the state reported 19,334 cases, according to the CDC — before the widespread availability of coronavirus vaccinations,” The Post’s Timothy Bella and Meryl Kornfield report.

About 49 percent of Florida’s population has been fully vaccinated. Hospital beds are overwhelmingly full of patients who did not receive the vaccine, and health systems are feeling the strain. The number of covid hospitalizations is close to breaking the record set by the state in July 2020.

“In addition to the highly transmissible delta variant, vaccine holdouts and the widespread resumption of normal activities have led to a surge in infections, hospitalizations and deaths nationwide. With the United States reporting more than 70,000 cases a day, case numbers have risen to levels not seen since February,” our colleagues write.

OUCH: Researchers estimate that there is about $140 billion in medical debt in the United States.

A study in JAMA used data from a randomly selected group of 40 million Americans with TransUnion credit reports to estimate just how much medical debt there is in country. The researchers found 17.8 percent of people had medical bills that were past due. More medical debt was in collection than any other kinds of debt, Erin Blakemore reports for The Post.

Debt was higher in the Midwest and South than in the Northeast. Although the average level of debt has fallen in the past decade, people in states that did not expand Medicaid had much lower drops in debt.

More in coronavirus news

Businesses are rethinking their coronavirus policies.

“Stunned business executives are struggling to adjust to the rapidly shifting environment caused by covid-19′s delta variant, rocked by a cascade of evolving mask and vaccine recommendations from federal, state and local officials. In many cases, they are instituting new mask or vaccine guidelines — or requirements — within hours of shifting government reports,” The Post’s Abha Bhattarai and Erica Werner report.

Walmart and Disney are among the latest companies to mandate vaccines for their employees. Walmart also has announced that it will give $150 to store and warehouse workers who get the vaccine. Ford Motor Co. announced last week that its employees in Georgia, Kentucky, Missouri and Florida will be required to wear masks regardless of vaccine status.

Elsewhere in health care

  • The Senate has unveiled the details of a $1 trillion bipartisan infrastructure proposal, The Post’s Tony Romm reports. The bill includes $55 billion to improve the country’s drinking water, including a program to replace every lead pipe. It’s a priority that has the backing of pediatric health experts who point to the dangerous health consequences of lead exposure for children. But the bill excludes many of the priorities outlined in Biden’s American Jobs Plan, including spending for long-term care. Some liberal Democrats have insisted that any new bipartisan deal focused on physical infrastructure must move in tandem with a larger spending package that includes many of Biden’s other priorities, such as the expansion of federal safety-net programs.
As the Senate moves forward with a $1 trillion bipartisan infrastructure package, on Aug. 1 some liberal Democrats warned they won’t vote on the package. (Amber Ferguson/The Washington Post)
  • The Biden administration may spur a renewed focus on preventing drowning — the second leading cause of death in children after birth defects, Christine Vestal writes for The Post. Experts say the CDC may receive drowning prevention funding for the first time that can be allocated to state public health agencies.
     
  • The number of Americans receiving welfare declined, even amid massive economic dislocation caused by the coronavirus pandemic, The Post’s Amy Goldstein reports. The odds of being able to stay on welfare often hinges on where you live. Thirteen states left in place rules last year requiring residents to work or look for a job to qualify for monthly checks from Temporary Assistance for Needy Families. In all but three of those states, the number of residents receiving cash assistance fell from February 2020 to the end of the year.

Sugar rush