CDC & Bureau of Prisons Bombshell Study: COVID-19 Vaccinated Just as Infectious as Unvaccinated

Scientists and health researchers with the U.S. Centers for Disease Control and Prevention (CDC) and the Bureau of Prisons, U.S Department of Justice, recently concluded a study, posting the results on the preprint server medRxiv.  Funded by the CDC, the study investigators probed the extent to which vaccinated persons who become infected with COVID-19, so-called breakthrough infections, contribute to transmission. The federally employed investigators sought to better understand transmission among highly vaccinated federal prison inmates during a Delta-variant-driven surge. What were the markers of viral shedding in vaccinated and unvaccinated prisoners? After this federally funded study, it becomes clearer that vaccinated persons remain just as contagious as unvaccinated persons should breakthrough infections be relevant.

The Study

The study team secured informed consent of participating incarcerated participants with confirmed COVID-19 infection who provided mid-turbinate nasal specimens daily for ten (10) consecutive days while reporting symptoms via questionnaire. 

The study team tested 978 samples (derived from 95 participants) with real-time reverse transcription-polymerase chain reaction (RT-PCR), viral whole-genome sequencing and viral culture. The investigators analyzed duration of participant RT-PCR positivity and viral culture positivity using survival analysis. 

Results

Of the 95 participants leading to 978 specimens, 78 (82%) were fully vaccinated and 17 (18%) were not fully vaccinated. The study team detected no significant differences in duration of RT-PCR positivity among fully vaccinated participants (median:13 days) versus those not fully vaccinated (median 13: days; p = 0.50), or in the duration of sample culture positivity (medians: 5 days and 5 days; p = 0.29).

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The authors report that the overall duration of sample culture positivity was shorter with the Moderna vaccine recipients versus Pfizer (p=0.048) or Janssen (p=0.003) vaccine residents. 

Conclusion: A Possible Bombshell

Individuals who are vaccinated and become infected via breakthrough infection with SARS-CoV-2 are no less infectious than unvaccinated persons. TrialSite suggests these findings build on the case that the vaccinated, if infected via breakthrough infection—which occurs with more frequency, are just as contagious as unvaccinated people. The federal government researchers know this and thus declare health agencies “should consider vaccinated persons who become infected with SARS-CoV-2 to be no less infectious than unvaccinated persons. These findings are critically important, especially in congregate settings where viral transmission can lead to large outbreaks.”

Obviously, this study isn’t yet peer reviewed and cannot be used as evidence but it most certainly represents a major data point for further study.

Lead Research/Investigator

Liesl M. Hagan, MPH, Epidemiologist, CDC (corresponding author)