Background Adults with intellectual disabilities (ID) may be at higher risk of COVID-19 death. We compared COVID-19 infection, severe infection, mortality, case fatality and excess deaths, among adults with, and without, ID.

Methods Adults with ID in Scotland’s Census, 2011, and a 5% sample of other adults, were linked to COVID-19 test results, hospitalisation data and deaths (24 January 2020–15 August 2020). We report crude rates of COVID-19 infection, severe infection (hospitalisation/death), mortality, case fatality; age-standardised, sex-standardised and deprivation-standardised severe infection and mortality ratios; and annual all-cause mortality for 2020 and 2015–2019.

Findings Successful linkage of 94.9% provided data on 17 203 adults with, and 188 634 without, ID. Adults with ID had more infection (905/100 000 vs 521/100 000); severe infection (538/100 000 vs 242/100 000); mortality (258/100 000 vs 116/100 000) and case fatality (30% vs 24%). Poorer outcomes remained after standardisation: standardised severe infection ratio 2.61 (95% CI 1.81 to 3.40) and mortality ratio 3.26 (95% CI 2.19 to 4.32). These were higher at ages 55–64: 7.39 (95% CI 3.88 to 10.91) and 19.05 (95% CI 9.07 to 29.02), respectively, and in men, and less deprived neighbourhoods. All-cause mortality was slightly higher in 2020 than 2015–2019 for people with ID: standardised mortality ratio 2.50 (95% CI 2.18 to 2.82) and 2.39 (95% CI 2.28 to 2.51), respectively.

Conclusion Adults with ID had more COVID-19 infections, and worse outcomes once infected, particularly adults under 65 years. Non-pharmaceutical interventions directed at formal and informal carers are essential to reduce transmission. All adults with ID should be prioritised for vaccination and boosters regardless of age.