As COVID-19 vaccines were first being approved for emergency use in the United Kingdom, the UK Joint Committee on Vaccination and Immunisation decided to extend the interval before the second dose from 4 to 12 weeks to maximize the amount of people who could be vaccinated.
This week, two Lancet Infectious Diseases studies estimated vaccine effectiveness (VE) for the elderly after receiving just one dose.A study involving more than 10,000 people 65 years and older found a VE of 65% to 68% 5 to 7 weeks post-vaccination, while one involving 404 people 80 years and older found a VE from 71% to 80%."In both studies, the confidence intervals for estimates of vaccine efficacy are wide," write Maria Prendecki, MBBS, PhD, and Michelle Willicombe,