Study: Johnson & Johnson Two Dose High Efficacy 0:34
(CNN) -
The protection provided by COVID-19 vaccines appears to decline over time, especially for people over 65, an expert from the US Centers for Disease Control and Prevention said Wednesday. USA
Ruth Link-Gelles, who helps lead the Vaccine Efficacy Team at CDC, reviewed a series of studies that looked at the overall efficacy of vaccines in various groups between February and August and found similar patterns for vaccines from Pfizer and Modern, both made with mRNA.
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Efficacy began to decline a few months after people were fully vaccinated, which is defined as two weeks after their second dose of either vaccine.
"For people 65 and older, we saw significant decreases in VE (vaccine effectiveness) against infection with the delta variant for mRNA products," Link-Gelles said at a CDC vaccine advisers meeting.
“We also saw declines, particularly for Pfizer, for over 65s, which we are not seeing in younger populations.
Finally, there is evidence of VE that decreases against hospitalization in the delta period ”, he pointed out.
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CDC's Advisory Committee on Immunization Practices will meet to discuss the possible need for booster doses of vaccines and will discuss the effectiveness and safety of vaccines in general.
Pfizer has asked the US Food and Drug Administration to approve a booster dose of its vaccine for people 65 and older.
The FDA's own vaccine advisers have recommended a booster only for people 65 and older, those with underlying conditions that put them at high risk for serious disease, and for people whose jobs put them at high risk of exposure.
The United States will send an additional 500 million doses of covid-19 vaccines to other countries in 2022
Link-Gelles said that, in general, the effectiveness of Moderna's vaccine is higher than the vaccine manufactured by Pfizer / BioNTech.
For the Johnson & Johnson vaccine, the effectiveness of the vaccine increases over time, even after the delta variant has dominated.
A study called SUPERNOVA looked at veterans between February and August of this year.
In that study, the Pfizer vaccine provided 92% protection against hospitalization for people ages 18 to 64, and 77% for those over 65, Link-Gelles said.
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The Moderna vaccine provided 97% protection against hospitalization for people ages 18 to 64 and 87% for those 65 and older.
Effectiveness did not appear to be affected by the arrival of the delta variant, the study found.
A study called IVY looked at adults hospitalized in 18 states between March and August.
The efficacy of the Pfizer vaccine decreased from 91% 14 to 120 days after full vaccination, to 77% three months or more after full vaccination.
The effectiveness of Moderna's vaccine did not really decline, remaining at 92% or 93% in that study.
In a study of 4,000 healthcare staff, first responders, and other front-line workers at eight sites who were assessed weekly regardless of symptoms, the vaccine's protection against any infection decreased from 91% before delta to 66% during delta.
Covid-19 vaccines
