A federally funded study taking place at 21 college campuses will test how well Moderna's COVID-19 shot prevents vaccinated people from spreading the coronavirus,
The Washington Post reported.
Clinical trials have shown that the
Moderna vaccine is more than 94% efficacious at preventing illness from COVID-19, and that the shots are especially protective against severe disease, hospitalization and death from the virus. However, the clinical trials were not designed to answer an important question: Can vaccinated people still carry the
coronavirus in their nose and mouth and unwittingly spread it to others?
Real-world studies in
Israel and the
U.K. hint that COVID-19 vaccines cut down the risk of both symptomatic and asymptomatic infections, meaning those without any outward signs of illness, the Post reported. These two studies each focused on the
Pfizer and
AstraZeneca vaccines, respectively. Another study in 4,000 health care and essential workers in the U.S. provided additional evidence that the Pfizer and Moderna
vaccines protect against all infections, including those without symptoms,
Stat News reported.
Related: Quick guide: COVID-19 vaccines in use and how they work
While these studies provide clues that vaccinated people may be less likely to spread the
virus, because they appear to avoid infection overall, they cannot confirm this conclusively. The new college campus study, called PreventCOVIDU, will attempt to directly answer the question through contact tracing — where COVID-19 infections are tracked among vaccinated people, unvaccinated people and a large group of their close contacts.
Tracking if and how infections ripple through this large group of people should help reveal how often vaccinated people pass the virus to those around them, regardless of whether the vaccinated person falls ill.
"This study is addressing the important issue about what does it mean to be vaccinated, as far as your risk for transmitting SARS-CoV-2 to people in your bubble of trust," Dr. Lilly Immergluck, a pediatric infectious-disease specialist at Morehouse School of Medicine in Atlanta, told the Post.
