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CU Boulder study aims to determine if vaccinated people can transmit COVID-19

Posted at 9:59 PM, Mar 30, 2021
and last updated 2021-03-31 11:40:01-04

BOULDER, Colo. — A study among students at the University of Colorado Boulder (CU) aims to help determine if the Moderna vaccine reduces or prevents the transmission of COVID-19.

CU is one of 21 universities taking part in the national trial. The National Institute of Health is funding the five-month study at Fred Hutchinson Cancer Research Center in Seattle.

Currently, more than 15% of the population in the United States is fully vaccinated, but that doesn’t guarantee a return to normal.

Recently, clinical trials for the Moderna and Pfizer vaccines only focused on the effectiveness of reducing and preventing the severity of the disease. According to the Centers for Disease Control, medical experts are still learning how well COVID-19 shots keep people from spreading the virus.

“There is some data available demonstrating that the vaccine is effective at reducing transmission, so we want to add to that information and make that information more clear,” said Chris DeSouza, a professor of integrative physiology at CU.

The study will focus on the Moderna vaccine.

Olivia Parsons, a senior at CU, is one of 12,000 students across the U.S. between 18 and 26 years old that will take part in the study. CU is hoping to enroll 700 students in the trial. Volunteers will be split into two groups: half will receive the Moderna shot, and the other half will wait four months.

“I think you have to think about the greater good and the general public ahead of yourself. While, yes, you are receiving the vaccine, which is a great bonus, the research that's coming out of it is impacting so many people,” Parsons said.

She also had to enroll three close contacts in the trial.

“If anyone tests positive, of course, we will then follow up with their close contacts and determine whether those close contacts, in turn, become infected,” DeSouza said.

Volunteers will do nasal swabs daily, get tested twice a week on campus and have their blood drawn periodically.

“The major breakthrough will be two things: one, is the Moderna vaccine effective in college students; two does it limit or prevent transmission,” DeSouza said. “If no one around you is becoming infected, that would give us an indication that the virus is effective at reducing transmission.”

The data will also help determine if the general public should continue to wear masks and social distance.

The results of the vaccine transmission research are expected to be available by late fall or winter of 2021.

Student volunteers are still needed in the study. You can learn more by emailing,