COVID-19 delta variant can easily spread in homes despite vaccination status, study shows

A new study suggests people vaccinated against COVID-19 can still easily spread the delta variant among households just as likely as people who are unvaccinated.

The United Kingdom-based study was published in "The Lancet Infectious Diseases" journal Friday.

Researchers studied 621 symptomatic COVID-19 patients from September 2020 to September 2021. 

The results showed that those who were vaccinated had a similar viral load of the delta variant as those who were unvaccinated. It also found that in households that were exposed to the delta variant, 25% of vaccinated people still contracted the virus compared to 38% of unvaccinated people. 

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"Our findings help to explain how and why the delta variant is being transmitted so effectively in populations with high vaccine coverage," the study’s authors pointed out. 

"While the primary aim of vaccination is to protect individuals against severe COVID-19 disease and its consequences, the extent to which vaccines reduce onward transmission of SARS-CoV-2 is key to containing the pandemic," the study's authors continued. 

Researchers agree that COVID-19 vaccines are effective in preventing severe symptoms and death but they said vaccination isn’t sufficient enough to prevent a delta variant outbreak inside a home. They believe vaccine boosters and expanding vaccinations to teenagers will help keep hospitalizations and death caused by the delta variant low. 

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The Food and Drug Administration on Friday paved the way for children ages 5 to 11 to get Pfizer’s COVID-19 vaccine. The FDA cleared kid-size doses — just a third of the amount given to teens and adults — for emergency use, and up to 28 million more American children could be eligible for vaccinations as early as next week.

On Tuesday, advisers to the Centers for Disease Control and Prevention will make more detailed recommendations on which youngsters should get vaccinated, with a final decision by the agency’s director expected shortly afterward.

The similarly made Moderna vaccine also is being studied in young children, and both Pfizer and Moderna also are testing shots for babies and preschoolers.

Tumbling COVID-19 case counts have some schools around the U.S. considering relaxing their mask rules, but deaths nationally have been ticking up over the past few weeks, some rural hospitals are showing signs of strain, and cold weather is setting in.

The easing of the summer surge has been attributed to more mask-wearing and more people getting vaccinated. The decrease in case numbers could also be due to the virus having burned through susceptible people and running out of fuel in some places.

Still, there are some troubling indicators, including the onset of cold weather, which sends people indoors, where the virus can more easily spread. With required mask use reduced in much of the U.S., the University of Washington's influential COVID-19 forecasting model is predicting increasing infections and hospitalizations in November.

The Associated Press contributed to this report. This story was reported from Los Angeles.