WEDNESDAY, Aug. 18, 2021 (HealthDay News) -- Preliminary data from seven U.S. states show that the arrival of the Delta variant in July may be fueling a rise in breakthrough infections among the fully vaccinated.
At least 1 in every 5 new COVID-19 cases in six of these states have involved vaccinated people, with higher percentages of hospitalizations and deaths among these folks than had previously been seen in all seven states, The New York Times reported.
Still, the absolute numbers of vaccinated people made sick by COVID-19 remains very low, experts said, and the vaccines are still very potent weapons against severe disease.
If breakthrough infections are becoming more common, "it's also going to demonstrate how well these vaccines are working and that they're preventing hospitalization and death, which is really what we asked our vaccines to do," said Anne Rimoin, an epidemiologist at the University of California, Los Angeles, told the Times.
Importantly, a vast majority of vaccinated people who are hospitalized for COVID-19 are likely to be older adults or those who have weakened immune systems. CDC data show that 74% of breakthrough cases are among adults aged 65 or older.
The numbers suggest that people who are at higher risk for complications from COVID-19, and anyone who lives with a high-risk person, "really needs to seriously consider the risks that they're taking now," Dr. Dean Sidelinger, a state epidemiologist and state health officer for Oregon, told the Times.
"Remember when the early vaccine studies came out, it was like nobody gets hospitalized, nobody dies," Dr. Robert Wachter, chairman of the department of medicine at the University of California, San Francisco, told the Times. "That clearly is not true."
"If the chances of a breakthrough infection have gone up considerably, and I think the evidence is clear that they have, and the level of protection against severe illness is no longer as robust as it was, I think the case for boosters goes up pretty quickly," Wachter added.
The seven states analyzed by the Times -- California, Colorado, Massachusetts, Oregon, Utah, Vermont and Virginia -- were chosen because they are keeping the most detailed data, the Times said. It is not certain whether the trends in these states would hold across the country.
The increases seen are largely due on the mathematics of mass vaccination: Scientists have always expected that as the number of vaccinated people exponentially grows, vaccinated people will show up more frequently than before in tallies of the severely ill and dead.
"We don't want to dilute the message that the vaccine is tremendously successful and protective, more so than we ever hoped initially," said Dr. Scott Dryden-Peterson, an infectious disease physician and epidemiologist at Brigham & Women's Hospital in Boston. "The fact that we're seeing breakthrough cases and breakthrough hospitalizations and deaths doesn't diminish that it still saves many people's lives."
The states' data do confirm that vaccinated people are still far less likely to become severely ill or to die from COVID-19. In California, the 1,615 hospitalizations of people with breakthrough infections as of Aug. 8 represents just 0.007% of nearly 22 million fully immunized residents, and breakthrough deaths constitute an even smaller portion, the Times reported.
But in six of the states, breakthrough infections accounted for 18% to 28% of recorded cases in recent weeks, the newspaper said. These numbers are likely to be low, because most fully immunized people may not feel ill enough to seek a test.
Breakthrough infections accounted for 12% to 24% of COVID-19 hospitalizations in the states, the Times found. The number of deaths was too small to arrive at a solid number, although it does appear to be higher than the CDC estimate of 0.5%.
The latest numbers make a good case for booster shots, and a recent survey showed that seniors can't wait to get one: Among vaccinated Americans, 72 percent of those who are 65 or older already say they want a booster shot.
The U.S. Centers for Disease Control and Prevention has more on COVID-19.
SOURCES: The New York Times