Preceding the COVID-19 vaccine era
It should be noted that the research was conducted in fall 2020, before access to COVID-19 immunization.
“The study was performed prior to vaccine availability in a cohort of young people. It adds further data to support prior observations that the majority of infections are spread by a much smaller group of individuals,” David Hirschwerk, MD, said in an interview.
“Now that vaccines are available, I think it is very likely that a repeat study of this type would show diminished transmission from vaccinated people who were infected yet asymptomatic,” added Dr. Hirschwerk, an infectious disease specialist at Northwell Health in New Hyde Park, N.Y., who was not affiliated with the research.
Mechanism still a mystery
“This finding has been in the literature in piecemeal fashion since the beginning of the pandemic,” Dr. Sawyer said. “I just think we were the first to realize the bigger implications of these plots of viral load that we have all been seeing over and over again.”
How a minority of people walk around asymptomatic with a majority of virus remains unanswered. Are there special people who can harbor these extremely high viral loads? Or do many infected individuals experience a short period of time when they carry such elevated levels?
The highest observed viral load in the current study was more than 6 trillion virions per mL. “It is remarkable to consider that this individual was on campus and reported no symptoms at our testing site,” the researchers wrote.
In contrast, the lowest viral load detected was 8 virions per mL.
Although more research is needed, the investigators noted that “a strong implication is that these individuals who are viral ‘super carriers’ may also be ‘superspreaders.’ ”
Some of the study authors have financial ties to companies that offer commercial SARS-CoV-2 testing, including Darwin Biosciences, TUMI Genomics, Faze Medicines, and Arpeggio Biosciences.
A version of this article first appeared on Medscape.com.