Reference:
Riemersma, K. K., Haddock, L. A. III, Wilson, N. A., Minor, N., Eickhoff, J., Grogan, B. E., Kita-Yarbro, A., Halfmann, P. J., Segaloff, H. E., Kocharian, A., Florek, K. R., Westergaard, R., Bateman, A., Jeppson, G. E., Kawaoka, Y., O’Connor, D. H., Friedrich, T. C., & Grande, K. M. (2022). Shedding of infectious SARS-CoV-2 despite vaccination. medRxiv. https://doi.org/10.1101/2021.07.31.21261387
Summary:
The emergence of the SARS-CoV-2 Delta variant raised concerns about the transmission capabilities of vaccinated individuals. A study analysed 20,431 nasal swab specimens from vaccinated (n=9,347) and unvaccinated (n=11,084) individuals between June and December 2021, revealing no significant difference in cycle threshold (Ct) values based on vaccination status. Notably, 67% of vaccinated individuals had low Ct values (<25), indicating potential infectiousness. The study demonstrated that vaccinated individuals could shed infectious virus at similar rates and titers to unvaccinated counterparts. This suggests that vaccinated individuals can contribute to the spread of COVID-19, highlighting the importance of ongoing public health measures, even amidst high vaccination rates. The findings underscore the necessity for continued vigilance in testing andadherence to preventative measures to mitigate transmission risk.