Pfizer Jab In Young People Only 20%
Researchers with the U.S. Centers for Disease Control and Prevention
(CDC) analyzed test results from sites across the United States and
determined that the vaccine was 60 percent effective two to four
weeks after 12- to 15-year-olds got the second of the two-dose
primary regimen.
But the effectiveness, measured against symptomatic illness, quickly
plummeted, hitting 20 percent around month two and zero around
month five.
After that, recipients in the age group were more likely to be
infected by COVID-19.
Vaccine effectiveness was no longer significantly different from
0 during month 3 after the second dose, the researchers wrote in the
study, which was published by the Journal of the American Medical
Association (
https://bit.ly/3lomISK).
Pfizer, its partner BioNTech, and the CDC didnt respond to requests
for comment.
The analyzed tests were performed between Dec. 26, 2021, and Feb.
21, 2022. Some 47,700 tests among 12- to 15-year-olds were included,
with about half being unvaccinated. The testing data was on the
Increasing Community Access to Testing, a program funded by the
U.S. Department of Health and Human Services that contracts with
pharmacy chains to perform drive-through testing. The testing data
was supplemented by information in questionnaires filled out by
adults with the adolescents.
Limitations of the study included vaccination being self-reported.
The study was funded by the U.S. government.
The study also found that vaccine effectiveness against symptomatic
infection plunged quickly for those 5 to 11 years old, starting at 60
percent but hitting 23 percent just one month later.
One way to combat the negative effectiveness, researchers said, was
to get a booster dose.
Of the 906 12- to 15-year-olds who got a third, or booster, dose, the
effectiveness was measured at 71 percent two to six weeks after
receipt.
Other studies, though, show that the protection from a booster, like
that from the primary regimen, quickly wanes.
Given the well-established pattern of waning mRNA VE after 2 doses
and early evidence of waning of booster dose protection in adults,
monitoring the duration of protection from booster doses in
adolescents will be important, researchers said.
Both the Pfizer and Moderna vaccines are built on messenger RNA
(mRNA) technology. VE refers to vaccine effectiveness.
In another study (
https://bit.ly/3yL0cLJ) published by the same
journal on May 13, New York researchers reported the gap of infection
and hospitalization risk between unvaccinated and vaccinated youth
narrowing over time, with vaccinated 5- to 11-year-olds being
infected at a rate of 62 per 100,000 and unvaccinated being infected
at a rate of 70 per 100,000.
That was an incidence rate ratio of 1.1; the rate ratio for 12- to
17-year-olds was 2.
The protection also waned considerably against hospitalization over
time, researchers found.
They said that the findings support efforts to increase vaccination
coverage in children and adolescents.
