High COVID-19 vaccination rates were expected to reduce transmission of SARS-CoV-2
in populations by reducing the number of possible sources for transmission and thereby
to reduce the burden of COVID-19 disease. Recent data, however, indicate that the
epidemiological relevance of COVID-19 vaccinated individuals is increasing. In the
UK it was described that secondary attack rates among household contacts exposed to
fully vaccinated index cases was similar to household contacts exposed to unvaccinated
index cases (25% for vaccinated vs 23% for unvaccinated).