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As more get vaccinated, spread and severity of COVID-19 worse among unvaccinated


A viral image pushes back against data showing that COVID-19 has a bigger impact on people who are not vaccinated than on those who are.

The image states:

“2020: Peak active cases — 9,034,460; vaccinated — 0%.

“2021: Peak active cases — 9,243,682; vaccinated — 71%.

“I hate to break this to you, but this is not a ‘pandemic of the unvaccinated.’”

The claim is made in an image of a tweet that was widely shared on Facebook. The Facebook post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

New cases of COVID-19 peaked again in August 2021, after the more contagious delta variant became predominant in late June 2021, and there are cases of breakthrough infections among people who have been fully vaccinated.

But the virus is much more likely to spread, and the disease presents far greater health risks, among the unvaccinated than the vaccinated.

The numbers

It’s not clear what “peak active cases” are, or what the numbers stated in the image are counting. Hannah Ritchie, head of research at the England-based Our World in Data research organization, said peak active cases is not a metric commonly used by researchers. A spokesperson for the U.S. Centers for Disease Control and Prevention said the CDC does not use that term.

Daily new cases in the United States peaked at 293,000 on Jan. 6, 2021, as vaccines were being rolled out, and at 188,000 on Aug. 12, 2021, after the more contagious delta variant had taken hold, according to the CDC.

“The epidemic has matured, and the virus has evolved, so comparing overall counts in 2020 and 2021 isn’t an apples-to-apples comparison — much has changed,” said Dr. Stuart Ray, an infectious disease specialist and professor of medicine at Johns Hopkins University.

“When comparing vaccinated to unvaccinated people, rates are lower in vaccinated people, whether looking at likelihood of testing positive; duration of testing positive; the number of close contacts infected by an infected person; the likelihood of needing hospitalization or intensive care unit care; and the likelihood of death,” Ray said.

In total, there have been more than 41 million cases of COVID-19 in the U.S., according to Johns Hopkins University.

Vaccination differences

The CDC in May 2021 stopped monitoring breakthrough cases — infections in fully vaccinated people — that did not result in hospitalization or death. Zeroing in on severe breakthrough cases is meant to provide vaccine researchers with more complete and reliable data on the cases they’re most concerned about, since not all people with breakthrough infections can be identified, particularly those with asymptomatic or mild illness who do not get tested.

So, we don’t know exactly how many vaccinated people are coming down with COVID-19.

But we reported in September that a New York Times analysis found that the average vaccinated American’s odds of experiencing a breakthrough infection are roughly 1-in-5,000 a day and 1-in-10,000 in highly vaccinated states.

That analysis relied on data from three places that have reported detailed data on COVID-19 infections according to vaccination status: Utah; Virginia; and King County in Washington state. A Kaiser Family Foundation researcher used CDC data to calculate the chance of a breakthrough case across all jurisdictions. She found the chance from June 20 to July 17 was lower than what the Times had found: about 1-in-5,000 per week, or about 1-in-35,000 per day.

Meanwhile, data continue to come in showing how much more dangerous COVID-19 is for the unvaccinated.

On Sept. 10, 2021, the CDC analyzed vaccine effectiveness across 13 jurisdictions from April 4 to July 17 and matched that data to vaccine registries from those areas. It found that after delta became the most dominant variant, unvaccinated people were five times more likely to be infected than fully vaccinated people, and more than 10 times more likely to be hospitalized or die.

“Across 13 U.S. jurisdictions, incidence rate ratios for hospitalization and death changed relatively little after the delta variant reached predominance, suggesting high, continued vaccine effectiveness against severe COVID-19,” the report said.

In August, we rated  False a claim that “it is the vaccinated, not the unvaccinated, spreading mutant variants.”

We found that the alpha, beta, gamma and delta variants were first detected in unvaccinated populations. We also found that, while research has found that vaccinated people who become infected with COVID-19 are able to transmit the virus, studies also show that unvaccinated people are far more likely to contract and spread the delta variant than vaccinated people.

Our ruling

A viral image claimed that “peak active cases” of COVID-19 for 2020 vs. 2021 show “this is not a ‘pandemic of the unvaccinated.'”

“Peak active cases” is not a term used by researchers and it was not clear what figures listed in the image were counting.

New cases in the U.S. peaked in August 2021, after the more contagious delta variant became predominant. But data show the unvaccinated are far more likely to become infected, and to become hospitalized or die, than the vaccinated.

We rate the post False.

Our Sources

Facebook, post, Sept. 12, 2021

Twitter, tweet, Sept. 11, 2021

Email, Dr. Stuart Ray, an infectious disease specialist and professor of medicine at Johns Hopkins University, Sept. 16, 2021

Email, Hannah Ritchie, head of research at Our World in Data, Sept. 17, 2021

New York Times, “Coronavirus in the U.S.: Latest Map and Case Count,” updated Sept. 16, 2021

Johns Hopkins University, “Cumulative cases,” Sept. 16, 2021

PolitiFact, “Safer to be unvaccinated against COVID-19? In several ways, that’s False,” Aug. 4, 2021

PolitiFact, “Evidence shows that COVID-19 variants are largely spread among unvaccinated people,” Aug. 25, 2021