Trial Underway To Determine Whether COVID-19 Vaccines Prevent Spread

Mar 26, 2021, 4:32 PM | Updated: Jul 12, 2023, 4:12 pm

SALT LAKE CITY — Researchers in Washington state have launched a nationwide clinical trial to answer one of the lingering questions about the COVID-19 vaccines — whether they prevent infection as well as spread and transmission of the virus.

So far, the vaccine has been proven effective at keeping the vaccinated person from getting sick, but health experts still don’t know for certain whether that person can still become infected and spread COVID-19.

“If we could find that the vaccine is very effective at preventing asymptomatic infection, and then also secondarily transmissions to others, then we could begin to lighten up probably even more on these restrictions that we have after people get fully vaccinated,” said Dr. Emily Spivak, an associate professor of medicine in the Division of Infectious Diseases at University of Utah Health.

The results will help individuals and communities make science-based decisions about mask use, social distancing and gathering.

If the virus is not spread after a person has been vaccinated, they would not need to wear masks.

“People keep saying, ‘Well, I’m getting my vaccine,’ but then we’re saying, ‘But you still need to wear your mask when you’re in public, you still need to avoid large crowds, large gatherings, and poorly-ventilated spaces because we don’t know if you can get it and not know that you got it from that setting and then transmit it to others,’” said Spivak.

Thousands of college students on more than 20 campuses will be vaccinated and monitored over a five-month period. The students will swab their noses daily for COVID infection, provide periodic blood samples and fill out electronic questionnaires.

People identified as close contacts of the students will also provide samples. 

Transmission of the virus from vaccinated students will be determined by the infection rate in the close contacts.

If results come soon enough, Utah’s vaccination strategy could change.

If you find that the vaccines really drop infectiousness and transmission, then maybe we don’t have to vaccinate as many people,” said Spivak.

That might matter in the next couple of months when eagerness for vaccination is replaced by hesitancy. 

Researchers said they hope to have answers before the start of school in the fall.

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Trial Underway To Determine Whether COVID-19 Vaccines Prevent Spread