Vaccinated individuals with breakthrough infections with the Delta variant still have the risk of transmitting the virus even to their vaccinated family members, British researchers found.

Secondary attack rates after Delta exposures were 38% in unvaccinated contacts and 25% in vaccinated contacts, a non-significant difference, though "consistent with the known protective effect of COVID-19 vaccination against infection," wrote Ajit Lalvani, MD, of Imperial College London, and colleagues in The Lancet Infectious Diseases.

...