COVID-19 vaccines and the Delta variant

Updated: Dec 15, 2021


While massive vaccination campaigns are ongoing worldwide, the inability to vaccinate a vast majority to achieve the theoretical threshold of ‘herd immunity' has resulted in SARS-CoV-2 circulating at a more than desirable rate and newer variants emerging. Among the many variants, the Delta variant has successfully dominated the globe, and newer data on its infectiousness and transmission is developing day by day.


Looking directly at how well the Oxford-AstraZeneca and Pfizer-BioNTech vaccines prevent the spread of the Delta variant, one of the first studies of its kind demonstrates that people who received two doses of the COVID-19 vaccines and later contracted the Delta variant were less likely to infect their close contacts compared to the unvaccinated people infected with Delta. Along with several other unknowns and anomalies, unfortunately, the vaccine’s beneficial effect on Delta transmission waned to almost negligible levels over time, with reports of a vaccinated person with a Delta infection transmitting the virus more frequently than someone infected with Alpha.


These alarming findings underscore the importance of concerted efforts of vaccination, social distancing, and proper mask-wearing, even by the vaccinated individuals, to control the pandemic.


Click here to learn more about this study.

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