#COVID vaccines cut the risk of transmitting Delta — but not for long
▻https://www.nature.com/articles/d41586-021-02689-y
“There’s a step-change with Alpha versus Delta, but then there’s also a change over time,” says co-author David Eyre, an epidemiologist at the University of Oxford, UK. The results “possibly explain why we’ve seen so much onward transmission of Delta despite widespread vaccination”.
But the results also offer the “intriguing possibility that if you do run a booster campaign because you want to protect individuals, it may also have this effect of reducing transmission,” says Eyre.
Booster campaigns raise a new uncertainty, says Stephen Riley, an infectious-diseases researcher at Imperial College London: “whether the same waning of protection from infectiousness will occur after the third dose”.
The study has not yet been peer reviewed.