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New study shows all three vaccines lose protective power over six months

Local doctors say the vaccines still hold up when preventing death, but it's important to get a booster shot when you're eligible.

MINNEAPOLIS — As COVID-19 cases continue to surge across Minnesota, a new study reveals the vaccines are losing some of their protective power.

The study is one of the most comprehensive looks at how the vaccines performed in "real life".  

The eight-month-long study is comprised of about 800,000 veterans — about 500,000 of whom were vaccinated.

The data recently published in the journal Science shows the vaccines' effectiveness dropped sometimes up to 85% over six months. 

"I think that it is a little bit concerning that we've seen some decrease in effectiveness over time, but I wouldn't say it was completely unexpected," said Allina Health's Vice President of Medical Operations for Primary Care Dr. Kevin Best.

The study says immune systems and their levels of defense can wane over time. Plus, the highly transmissible delta variant may contribute to the vaccine's falling effectiveness. 

It was especially noticeable with the single dose of Johnson & Johnson — its effectiveness falling from 86% to 13%.

Pfizer fell from 87% to 45% and Moderna fell from 89% to 58% over those six months, according to the study. 

But that doesn't mean the vaccines don't work. 

"The real test and the real bar we should be measuring this, or for those deciding whether they want to get vaccinated or not, is the difference between vaccinated and not getting vaccinated," said Best. "It's clearly, markedly superior to be vaccinated versus not." 

Best says of all the nearly 300 patients in Allina hospitals with COVID right now, more than half are unvaccinated. The same goes for those in the ICU and on ventilators.

Credit: KARE

"Having more people not vaccinated allows that virus to continue to change overtime and could increase the risk of less effectiveness of the vaccines down the road," said Best.

Dr. Best also said, while this is a large and well-done study, it is just one study. But, he said it underscores the importance of wearing a mask and staying home if you're sick, as well as getting a booster shot if you're eligible.

"The study shows to watch that immunity and that’s when boosters are recommended and who gets boosters rejuvenates that immunity," said Best.

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