A recently published article by the CDC and authored by Gharpure et al states that rate of transmission of COVID-19 among fully vaccinated and unvaccinated may not be too different, rather that the viral load reduction is what is driving the differences between the two groups. Unsurprisingly, the fully vaccinated have an advantage over the unvaccinated by having a shorter period of transmissibility, this is further complicated when large mass gathering events occur. During these events, vaccination does not offer much protection against mild infection, as seen in this study where 74% of people infected in a large outbreak in Provincetown, MA that occurred in July 2921, were associated with breakthrough infections of the delta variant. 918 persons who were included in this study because they experienced breakthrough infections included 504 (55%) individuals who received the Pfizer/BioNTech vaccine, 293 (32%) received the Moderna vaccine, and 121 (13%) received the Johnson & Johnson vaccine.
Based on this study, the authors reinstate the need to remain fully masked regardless of vaccine status.
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