Skip to Content

Can you transmit COVID-19 even after vaccination? CU Boulder conducting new study

CU Boulder vaccine study
CU Boulder

BOULDER, Colo. (KRDO) -- A new study at CU Boulder seeks to better understand COVID-19 transmission after vaccination.

This comes as Colorado considers further easing COVID-19 restrictions before the end of April.

According to CU Boulder researchers, reopening the state largely depends on vaccine efficacy. This means it's not just about protecting those who are already vaccinated from the virus, but preventing person-to-person transmission as well.

"We are pretty clear now that it will be very effective at preventing you from becoming sick," Professor Christopher DeSouza, said. "But, the big questions is whether it prevents transmission."

DeSouza is the Co-Principal Investigator for the study. CU Boulder is the first among 21 colleges in the U.S. that are participating in the trial, led by the federally funded COVID-19 Prevention Network.

"If you’re vaccinated and you do become exposed, once again to the virus, does being vaccinated prevent you from transmitting the virus to someone else?" 

At least 700 students from the college will participate in the study of more than 12,000 nationwide. CU Boulder senior Chase Willie received his first dose of the Moderna vaccine last Thursday.

"I kind of found that as an opportunity to be a part of a study that's actually making a big impact in the world," Willie said.

 He said he's hopeful the study's findings will help in the transition back to in-person learning this fall.

"A lot of our classes are going back in person, and I feel like people are having to re-adapt to that college experience."

Over the next five months, participants and their close contacts will be monitored for any signs of the virus through regular testing.

"This ties into a lot of the follow up questions that are important now regarding the vaccine," DeSouza said.

He said this includes discussions regarding how quickly COVID-19 safety restrictions should be lifted at the state and local level, as well as how soon vaccinated individuals should relax mask wearing or social distancing.

"It will absolutely determine whether those types of restrictions can be relaxed or relaxed in a safe way."

The study focuses on the Moderna vaccine. However, researchers said they're confident the results will also apply to other mRNA vaccines, like Pfizer. Results are expected to be finalized this fall.

Coronavirus / Health / Health / Local News / Reporter Stories / Video
Author Profile Photo

Jen Moynihan

Jen Moynihan is a weekend anchor and reporter for KRDO. Learn more about Jen here.



  1. They already did a study by the drug companies and the answers is : Yes, you can still get and transmit the covid after vaccination.

    1. Exactly. Vaccination cuts down on your chances of becoming infected, and mitigates the seriousness of your illness if you DO become infected again. But it doesn’t eliminate the possibility of becoming infected, and therefore doesn’t eliminate the ability to spread it.
      Does it reduce the likelihood of spreading the infection? I’m betting it does. But it doesn’t eliminate it.

  2. Food for thought for all of you…long read…if you research you find the truth!!

    The Ever-Moving Goal Post

    If you’ve paid attention, you’ve likely noticed that the goal post for “public safety” has been moved further and further away as we’ve gone along. At regular intervals, there’s been another Chicken Little warning that the sky is still falling and that we must not let down our guard.

    First it was the number of deaths that was cause for alarm. Now we know that many of the so-called COVID-19 deaths were not, in fact, caused by the virus, while erroneous epidemiological models predicted millions of deaths lest drastic measures were taken.

    As PCR testing took off, rising “case” loads seemed to confirm such dire predictions, sparking widespread panic. With 20/20 hindsight, we now realize that the cycle thresholds of these tests were set so high that even healthy, uninfected and noninfectious people tested positive.

    This, in turn, allowed for the myth of asymptomatic spread to take root, and that then became the fear trigger, with everyone being a potential threat, no matter how healthy they appear.
    The solution offered was for everyone to wear a mask at all times. Or two. Or perhaps three. Fortunately, even the experts backed off from suggestions of four layers. Yet, from the start, we knew, based on published science, that masks don’t work against viruses.

    As “cases” skyrocketed in tandem with fraudulent PCR testing, we were then told the best thing to do is shut everything down for two weeks to prevent overloading hospitals. Stay home, save a life, let the virus die out.

    But even though hospitals remained at functional capacity in most areas, as “cases” (read false positives) continued to rise, two-week lockdowns were turned into three weeks, then four. In some areas, lockdowns dragged on for months, yet it didn’t seem to have the desired effect on the case load. By this time, hospital capacity was entirely forgotten.
    As lockdowns continued and people started to grumble, the “experts” in charge of this global organization (or more accurately, reorganization) warned that this was the new normal. Settle in. Get used to it. The virus doesn’t seem to be going anywhere, so our only hope is a vaccine. We just have to keep it together until then, and then we’ll all be safe again.

    Alas, flies in the ointment appeared in the form of inexpensive treatments that worked just fine, and scientists and medical doctors sharing concerns about these novel “vaccines” that really aren’t and the public health dangers of lockdowns.

    Censorship unlike anything the world has ever seen before was launched, and vaccine-deniers became the new enemy — worse even than those pesky asymptomatic healthy people that refuse to wear a mask.

    Something had to be done about free thinkers and question-raisers, and so the goal post was moved again. The whole world, all 7-plus billion people, must get vaccinated, or else we’re all toast.
    This way, people will turn on each other and force each other to comply and stop with the questioning.

    We cannot simply undo the harm caused by flawed policies advocated by our elites, but we can resolve that we never let this happen to our country again. ~ Florida Gov. Ron DeSantis

    And so it continues. The sky hasn’t fallen yet, but we’re promised that unless we comply, it surely will. Any day now. Just a matter of time. Obey, and the experts will make sure we survive the inevitable pandemonium. Now, vaccine passports are being rolled out, and both private companies and entire nations are considering restricting any sense of normalcy to vaccinated-only. Aren’t you tired of chasing the goal post yet?
    Chicken Little’s Puppet Masters

    In a Wall Street Journal essay2 published March 18, 2021, Florida Gov. Ron DeSantis urges readers not to trust “the elites,” pointing out that “Influential people in public health, government and the media” have “failed to rise to the moment.” He goes on:

    “The COVID-19 pandemic represented a test of elites in the U.S., from public-health experts to the corporate media. The results have been disappointing. Policy makers who bucked the elites and challenged the narrative have been proven right to do so.

    To begin with, highly publicized epidemiological models were as consequential as they were wrong … The lockdowns failed to stop the virus but did a great deal of societal damage along the way — damage that a more targeted approach, seeking to reduce total harms, would have been able to avoid (and did, in places like Sweden and Florida) …

    Elites sent conflicting messages about the efficacy of cloth masks, the uniformity of risk across age brackets, the danger of outdoor transmission … Perhaps most damaging to public trust was the public-health campaign urging ‘15 Days to Slow the Spread’ … Going from ‘save the hospitals’ to ‘zero COVID’ represents one of the greatest instances in history of moving the goal post …

    While it was abundantly clear by May that schools represented low-risk environments for the spread of COVID and that the consequences of prolonged school closures were potentially catastrophic, the corporate media did its best to obscure the data and stoke fear and panic among parents and teachers.

    Had the media presented the data on schools in a rational fashion with proper context and perspective … millions of students would be in markedly better shape academically and socially.

    For months we were told to ‘trust the experts,’ but far too often over the past year those who were most influential in our society — in public health, government and media — proved incapable of rising to the moment … We cannot simply undo the harm caused by flawed policies advocated by our elites, but we can resolve that we never let this happen to our country again.”
    Who’s in Charge, Really?

    DeSantis’ definition of “elites” is basically prominent public health and corporate media leaders. That may be appropriate for the critique offered in his article, but even these influential individuals are mere foot soldiers in the bigger scheme of things.

    Above them towers a pyramidical power structure populated by globalist entities — nongovernmental organizations, think-tanks, private corporations and billionaire philanthropists — many of which we’ve never even heard of, and who rule without being seen.


    1. Nice. You could make good money writing books. You are wasted at your other job. Just enough facts to make it believable. Try a historical fiction novel. You just need to add how everyone in the end turns into zombies and you’ll be set.

  3. Have they never done this type of study on other vaccines? With all the vaccines already being given to people they should already know the likely answer.
    Given all the COVID19 mutations going on experts are now worried that current vaccines will be made less effective or useless. If so then game over, man.

    1. Never a study…if that’s what they call it. It was rolled out with a very small control group. And to anyone else who wants me to cite my info…do your own dayum research!

    2. @colo simple facts….your getting a FLU SHOT and it only protects vs. ONE STRAIN that’s why they are so worried about the mutations. there is NO CURE its a VIRUS. viruses CANNOT be cured.

  4. Just a WA state…152 people (only the tip of the iceberg) who have been fully vaccinated have tested positive for COVID. And do you think the media is going to give us true numbers nationally? Oh by the way…for those who are skeptics…do your own research.

    1. I know a local nurse and she was “fully vaccinated” and she got covid and spread it around to her family because she was told she couldn’t get it or spread it after the shots.
      The other fun facts is how they are not reporting the side affects accurately. Some states, countries, counties and cities have halted the vaccine over concerns of the crazy side affect that have come up.
      Why push a vaccine/shot on someone who is very little risk when they can still get and transmit it. I had the COVID and it was extremely mild for me. Didn’t even think I had it.

Leave a Reply

Skip to content