COVID vaccine protection wanes within six months - UK researchers

By William Schomberg and Ludwig Burger  August 26, 2021  Last Updated 16 hours 
ago 
https://www.reuters.com/business/healthcare-pharmaceuticals/covid-jab-protection-wanes-within-six-months-uk-researchers-2021-08-25/?utm_medium=Social&utm_source=twitter

Summary:

Within 5-6 months, effectiveness of Pfizer shot fell to 74%

Effectiveness of AstraZeneca shot fell to 67% after 4-5 months

LONDON, Aug 25 (Reuters) - Protection against COVID-19 offered by two doses of 
the Pfizer/BioNTech and the Oxford/AstraZeneca vaccines begins to fade within 
six months, underscoring the need for booster shots, according to researchers 
in Britain.

After five to six months, the effectiveness of the Pfizer jab at preventing 
COVID-19 infection in the month after the second dose fell from 88% to 74%, an 
analysis of data collected in Britain's ZOE COVID study showed.

For the AstraZeneca vaccine, effectiveness fell from 77% to 67% after four to 
five months.

The study was based on data from more than a million app users, comparing 
self-reported infections in vaccinated participants with cases in an 
unvaccinated control group.

More data is needed in younger people because participants who had their shots 
up to six months ago tended to be elderly as that age group was prioritised 
when the shots were first approved, the study authors said.

ZOE Ltd was founded three years ago to offer customised nutritional advice 
based on test kits. The company's ZOE COVID Symptom Study app is a 
not-for-profit initiative in collaboration with King’s College London and 
funded by the Department of Health and Social Care.

Under a worst-case future scenario, protection could fall below 50% for older 
people and healthcare workers by the winter, Tim Spector, ZOE Ltd co-founder 
and principal investigator for the study, said.

"It's bringing into focus this need for some action. We can't just sit by and 
see the protectiveness slowly waning whilst cases are still high and the chance 
of infection still high as well," Spector told BBC television.

Britain and other European nations are planning for a COVID-19 vaccine booster 
campaign later this year after top vaccine advisers said it might be necessary 
to give third shots to the elderly and most vulnerable from September.

The U.S. government is preparing to provide third booster doses starting in 
mid-September to Americans who had their initial course more than eight months 
ago.

"This is a reminder that we cannot rely on vaccines alone to prevent the spread 
of COVID," said Simon Clarke, Associate Professor in Cellular Microbiology at 
the University of Reading, who was not involved in the study.

A separate British public health study found last week that protection from 
either the Pfizer-BioNTech or the AstraZeneca vaccine against the now prevalent 
Delta variant of the coronavirus weakens within three months.

The Oxford University study found at the time that 90 days after a second shot 
of the Pfizer or AstraZeneca vaccine, their efficacy in preventing infections 
had slipped to 75% and 61% respectively. That was down from 85% and 68%, 
respectively, seen two weeks after a second dose.

Writing by William Schomberg and Ludwig Burger; Editing by Andrew MacAskill and 
Giles Elgood

----------------------------

Also, perhaps of interest ...

https://www.scientificamerican.com/article/covid-vaccines-show-no-signs-of-harming-fertility-or-sexual-function/

“COVID Vaccines Show No Signs of Harming Fertility or Sexual Function”

The novel coronavirus, in contrast, can disrupt both things in unvaccinated men 
and women

By Emily Willingham on August 24, 2021 ...
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