For unvaccinated, coronavirus is soaring again

An analysis of adjusted rates for cases, covid-19 deaths and hospitalizations shows the country’s summer upswing is slamming the unprotected while others enjoy freedom

U.S. averageMissouri averageAdjusted for unvaccinated population3152Dec. 16July 17

The country’s months-long decline in coronavirus cases, deaths and hospitalizations bottomed out in late June. The U.S. case rate, or seven-day average of new confirmed cases per 100,000 residents, was lower than at any point in the past 14 months.

But the spread of variants has pushed rates back up, especially in states with low vaccination rates. For example, Missouri’s overall case rate was below the country’s until it recently climbed above the U.S. average.

Almost half the U.S. population is fully vaccinated, however — and mostly protected from infection. In Missouri, if we remove vaccinated people from the population used to determine the case rate, the numbers paint a better picture of Missouri’s cases among unvaccinated people.

The result is startling: Missouri’s case rate among unvaccinated people is as high as its overall case rate in mid-January, near the state’s peak of coronavirus infections.

An earlier analysis of the adjusted coronavirus rates for cases, deaths and hospitalizations was published on May 26. This article uses similar methodology to examine current trends.

The country’s summer of freedom from covid-19 is turning savage for the half of the nation that is still not fully vaccinated.

Coronavirus cases are increasing almost exclusively in the unprotected population. So The Washington Post adjusted its case, death and hospitalization rates to account for that — and found that in many places, the virus continues to rage among those who have not received a shot.

As summer approached, the Centers for Disease Control and Prevention loosened mask recommendations and President Biden advised people to take off their masks and smile. Case numbers were dropping and millions of people were being vaccinated each day, suggesting a reduction in covid worries and a possible end to the pandemic.

But The Post’s adjustments for vaccinations reveal the rate among susceptible, unvaccinated people is 91 percent higher than the unadjusted case rates reported on coronavirus websites and state tracking systems.

With that adjustment, the national case rate for unvaccinated people is roughly the same as the unadjusted case rate was more than two months ago — and is rising. The national adjusted hospitalization rate has climbed to a point last seen in April, and the death rate is comparable to May’s unadjusted figures.

Unvaccinated people are being hit hardest where the more contagious, more powerful delta variant is dominating.

“With the arrival of delta, we will have two very different epidemics — one a mild cold in vaccinated individuals, and then we continue to have deadly infections in unvaccinated individuals,” said William Powderly, an infectious-disease specialist and director of the Institute for Public Health at Washington University in St. Louis.

“The people who need to come to hospital, who end up in the intensive care unit, and the people who die are almost exclusively unvaccinated individuals,” he said, noting that his hospital has three times the covid-19 patients it had in late June.

States with high rates among unvaccinated people

The adjusted rates in several states show the pandemic is spreading as fast among the unvaccinated as it did during the winter surge. Florida, Arkansas, Missouri, Nevada and Louisiana all have coronavirus case spikes among the unvaccinated, with adjusted rates double or triple the adjusted national rate. The adjusted rates of Utah, Kansas, Alabama and Alaska are slightly lower than those states.

Maryland, Virginia and the District of Columbia have adjusted rates below the national average. In the region, however, lower vaccination rates in the Black community have concentrated cases there to an extraordinary degree. Before vaccines, Black people represented about one-third of new coronavirus cases in Maryland and half in D.C. In the latest data, Black people represent just under half of the new cases in Maryland and more than 80 percent in D.C.

Average new daily cases per 100,000 residents

“We are on an exponential curve,” said Mark Williams, dean of the Fay W. Boozman College of Public Health at the University of Arkansas for Medical Sciences. “The delta variant is a different animal than the wild [original] variant. It is far more infectious and far more virulent.”

Williams expects the case rate among unvaccinated people to push higher than the winter surge. “I don’t see at the minute how we can avoid it,” he said.

People more likely to end up in the hospital

Like deaths, hospitalizations from covid-19 are almost entirely limited to unvaccinated patients. When current hospital utilization is spread across only the unvaccinated population, Nevada, Missouri, Arkansas and Florida have rates between double and triple the adjusted national rate.

“Ninety-eight percent of hospitalized individuals with covid in Arkansas are unvaccinated,” Williams said.

Even though treatments are better than they were originally, a larger share of patients are ending up in intensive care, and the fatality rate for those patients remains high, experts said.

“That’s just indicative of the more virulent quality of the delta variant,” Williams said. “It will make people sick, even people that are young and would not have felt any consequence from the original wild variant.”

Frighteningly, he said, far more children are being hospitalized, which was very rare until recently. As of mid-July, a dozen children were in Arkansas Children’s Hospital, he said, and two were on ventilators.

Virginia’s adjusted hospitalization is below the national average. Adjusted D.C. and Maryland rates are close to the national adjusted rate.

Average hospitalizations per 100,000 residents

The share of unvaccinated people among Maryland’s hospitalized covid patients has climbed from 89 percent in May and early June to 93 percent, according to a state analysis duplicating the findings announced across the country.

States with high death rates

The delta variant is driving death rates back up, even though deaths tend to lag more than a month behind surges in cases.

Covid-19 is killing almost exclusively unvaccinated people, according to Rochelle Walensky, director of the CDC.

Average new daily deaths per 1 million residents

Montana, New Mexico, Missouri, Arkansas, Florida, Arizona and Nevada all have adjusted death rates double the national adjusted rate or higher.

D.C., Maryland and Virginia have adjusted rates below the national average.

Experts repeatedly expressed frustration that people who think the pandemic is over are falling victim.

“We have the tool now to control this disease,” said Bart Hammig, a public health professor at the University of Arkansas. “We have a way to prevent the disease, to virtually eliminate all hospitalizations and deaths. Vaccinate. Vaccinate. Vaccinate.”

Rather than marking the end of the pandemic, the delta summer may be previewing the uptick experts are expecting in the fall in states such as Arkansas that have banned mask and vaccine mandates while pushing schools and colleges to open.

“That’s kind of like a viruses playground,” Williams said. “There will be a lot of transmission going on.”

Methodology

The Post adjusted coronavirus rates for cases, deaths and hospitalization over time by combining CDC data on cases, hospitalizations and vaccinations. The Post used a rolling seven-day average of daily cases, deaths and hospitalization. For vaccinations, The Post used the number of people who had received at least one shot as of each date.

For events like coronavirus infection, rates are usually calculated by dividing the number of cases by the number of people in the population. For example, if there are 12 cases among a population of 100 people, the rate would be 12 people per 100. The Post reduced the denominator to exclude most vaccinated people. So if 20 people got vaccinated, that would mean there were 12 cases out of the remaining 80 unvaccinated people, for an adjusted rate of 15 cases per 100 people.

Vaccination is not perfect in preventing infections, however, so The Post did not subtract the entire population of vaccinated people. Data shows the Pfizer-BioNTech and Moderna vaccines are about 90 percent effective in preventing cases among people who have received the shot. Cases among vaccinated people are called breakthrough cases. To be conservative, The Post estimated that up to 15 percent of the vaccinated population could still be infected.

So, in the example above, instead of removing all 20 vaccinated people, The Post removed 17. That would leave 12 cases among 83 people, for an adjusted rate of 14.5 cases per 100 people.

Using data released by the CDC’s Walensky, National Institute of Allergy and Infectious Diseases director Anthony S. Fauci and several states concerning effectiveness of vaccines for preventing hospitalization and death, The Post subtracted 90 percent of the vaccinated population from the denominator for hospitalization and 98 percent of the vaccinated population from the denominator for death rates.

The Post calculated the adjusted rates of cases, deaths and hospitalization for the nation and each state since the start of vaccination in December. Coronavirus case and death rates released by states are sometimes subject to time lags. State also sometimes review older cases and issue updated figures that reflect a backlog of old cases rather than a surge on that day.

Dan Keating analyzes data for projects, stories, graphics and interactive online presentations.
Leslie Shapiro has been a Graphics Reporter for The Washington Post since 2016, focusing on data visualization and new media storytelling.