AUSTIN, Texas – Baylor Scott & White hospitals in Round Rock, Temple and Waco, Texas, have been contributing to real-world studies reported by the Centers for Disease Control and Prevention that show a significant difference in people who have received a vaccine for the COVID-19 virus and people who have not.
The first study began as a flu study to test the effectiveness of that vaccine each year and has continued during the coronavirus pandemic to be a flu study as well as a COVID-19 study, once the Pfizer and Moderna vaccines began to be in use.
A new CDC report took data collected from this study from 24 hospitals (including the Round Rock, Temple and Waco hospitals) in 14 states, and looked at people ages 65 and older who came into the hospitals with flu- or COVID-19-like symptoms.
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The researchers then looked at whether the patients tested positive for COVID-19 and whether they had received one, two or zero doses of a COVID-19 vaccine. Because this study was looking at January through March data, it considered only injections of the Moderna or Pfizer vaccines. People who got the Johnson & Johnson vaccine were not considered for this study.
Using this real-world data, the study found the vaccines were 94% effective in protecting people who had received both doses of the vaccine and 64% effective for people who had gotten just one dose.
These numbers mirrored what was found in the large-scale vaccine clinical trials, but with a significant difference. People in the clinical trials tended to be healthier and younger, said Dr. Manjusha Gaglani, director of the Center for Research in Vaccines and Infections and chief of pediatric infectious diseases at Baylor Scott & White Health, “whereas here we are looking at everybody.”
This particular report looked at an age group that had the highest risk of severe complications and death from COVID-19, Gaglani said, as well as weaker immune systems, because our immune systems weaken as we age.
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“To see this (vaccine) response is very stunning,” Gaglani said.
She said she’s used to seeing responses to things such as flu vaccines in the 40% to 50% effectiveness range every year.
Baylor Scott & White also has been contributing to a study of health care workers, first responders and other frontline and essential workers that began last summer. Each week they were asked to send in a nasal swab to be tested and to answer surveys sent by text message about any symptoms they were having. Baylor Scott & White enrolled about 400 people working in the Temple area.
As these people became vaccinated, the study turned to also consider the effect of full vaccination and partial vaccination. It found a 90% effectiveness rate for the vaccine among people with both doses and 80% after one dose.
The thing that is notable about this study is that it is testing enrollees for COVID-19 regularly, regardless of their symptoms. That made it possible to catch cases that were asymptomatic.
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In this study, researchers learned that people who weren’t vaccinated and tested positive often did so before they experienced symptoms. Only 11% of those remained asymptomatic. For the rest, symptoms emerged a few days after the positive test.
The study recognized that without a vaccine it’s possible to pass on the virus without knowing you have it, as well as pointing out that the vaccine lowered the risk of both symptomatic and asymptomatic infection and transmission of the disease to others once people were fully vaccinated.
“This gives us some good data in what’s happening,” Gaglani said.
If people were on the fence about getting the vaccines and wanted to see how they work in the real world, “this is strong evidence in favor of vaccine effectiveness,” Gaglani said of both studies.
She is still seeing in her hospital lab in Temple a 5.6% COVID-19 positivity rate. About 2 in 100 people who are coming to the hospital for another reason, such as surgery, are testing positive, she said.
“We are catching underlying transmission going on,” she said. “That’s going to be an issue unless everyone is getting vaccinated.”
She is urging people to look at these two studies, which include local data, and “not sit on the fence anymore.”
“The vaccines are the best bet to not catch the infection or pass on the infection,” she said.
Follow Nicole Villalpando on Twitter: @nicvillalpando.