Triple-vaccinated are more likely than unvaccinated to have symptomatic COVID-19: study

Triple-vaccinated are more likely than unvaccinated to have symptomatic COVID-19: study

People who received two or three doses of a messenger RNA vaccine against COVID-19 were more likely to contract COVID-19 with symptoms, according to a new study.

The researchers found that vaccinated people were more likely to experience symptomatic COVID-19 than unvaccinated people, even if they had received a booster shot in addition to a primary series.

Researchers from the University of Utah and other institutions examined healthcare personnel, first responders, and other frontline workers from December 14, 2020, through April 19, 2022. Participants submitted self-collected nasal swabs weekly, as well as when participants experienced signs of illness.

Of those infected with COVID-19 since Omicron became the dominant strain of the virus in late 2021, 109 were unvaccinated and 634 were. And of those, 85 unvaccinated people were symptomatic, compared with 216 people who received a primary series of messenger RNA (mRNA) immunizations: two doses of either Pfizer either modern vaccines—and 327 people who received a booster in addition to the initial doses.

The researchers calculated the odds of getting symptomatic COVID-19 and other outcomes and found that unvaccinated participants were less likely to experience symptomatic COVID-19.

People who received a primary series of immunizations were more likely to experience a fever or chills in the first few months after vaccination, but then became less likely to experience those symptoms, even after receiving a booster. Initially, vaccinated people also experienced symptoms for a longer time. Unvaccinated people had more symptoms, were more likely to receive medical care, and missed more time from work.

The results differed from when the Delta variant was dominant, when unvaccinated people were more likely to have symptomatic COVID-19.

The study was published in the Journal of the American Medical Association.

The researchers used the HEROES-RECOVER network, which includes frontline workers such as garbage truck drivers and daycare workers. The network is funded by the Centers for Disease Control and Prevention.

Some 7,223 participants were enrolled, but 1,710 were excluded because they had been infected with COVID-19 before the study start date. Participants were excluded if they became infected within 13 days of receiving a second dose of vaccine or if they became infected within 13 days or later than 149 days of receiving a third dose of vaccine. . Most of the remaining participants did not become infected during the study time period.

The researchers said limitations of the study may have led to the finding that unvaccinated people were less likely to experience symptoms of COVID-19.

“Limitations in sample size and the ability to adjust models for potential confounders made it particularly difficult to interpret unexpected findings, such as a higher percentage of individuals with symptomatic disease among those vaccinated with the third dose of the vaccine among 14 and 149 days prior to infection with Omicron compared to those who were not vaccinated,” they wrote.

Sarang Yoon, an assistant professor in the Department of Family and Preventive Medicine at the University of Utah Health and one of the study’s authors, focused on how the vaccinated were better off in some categories.

“It is encouraging that mRNA vaccines resist these variants quite well,” Yoon said in a statement. “We know that breakthrough cases are more likely to occur with Delta and Omicron than with the initial strain, but the vaccines continue to do a good job of limiting the severity of infection.”

Zachary Stieber

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Zachary Stieber covers American and world news for The Epoch Times. It is based in Maryland.

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