In this preprint, Ladhani et al. analysed SARS-CoV-2 infection rate and seropositivity in residents and staff members from six care homes in London, UK. 40% of residents and 21% of staff had SARS-CoV-2 infection confirmed by RT-PCR at baseline. Five weeks later, 86% of the surviving residents and 73% of staff were tested for antibodies. Nearly all (97–100%) SARS-CoV-2 RT-PCR-positive individuals and the majority (66–85%) of SARS-CoV-2 RT-PCR-negative individuals seroconverted. Importantly, neutralizing antibodies were present in 89% of seropositive individuals, irrespective of gender, age, symptoms or PCR status. The finding that elderly residents can mount neutralizing antibody responses to levels similar to younger staff members offers hope for future vaccine efficacy in aged populations.