Prevalence of 406 rare diseases by ethnicity and recorded COVID-19 infection rates among 62.5 million people in England

Abstract Rare diseases (RD) are individually uncommon but collectively affect millions of people. Yet national estimates of their prevalence, especially across ethnic groups, are limited, and how the COVID-19 pandemic affected people with RD across ethnic groups is unknown. We aimed to estimate the prevalence of 406 RD by ethnicity, and to describe recorded COVID-19 infection across these RD and ethnic groups, in England. We conducted a cross-sectional study within the National Health Service (NHS) England Secure Data Environment, accessed via the British Heart Foundation (BHF) Data Science Centre’s CVD-COVID-UK/COVID-IMPACT Consortium, linking primary care, hospital, and mortality records for individuals alive on 31 July 2023. We calculated age- and sex-standardised prevalence for 406 RD, and recorded COVID-19 infection rates for the overall group, for each RD, and across the six-group Office for National Statistics (ONS) and 19-group NHS ethnicity classifications. Of 62.5 million people, 1.05 million (1.7%) had at least one of the 406 RD. Recorded COVID-19 infection was higher in the RD group than in the non-RD population (32.8% vs. 29.0%). Within the RD group, infection rates varied by ethnicity (e.g. 27.7% in the Pakistani and 23.8% in the Black African groups, versus 33.7% in the White British group) and by specific RD (24.6–41.2% among the 25 most common). Age- and sex-standardised prevalence also varied widely across ethnic groups, with substantial heterogeneity emerging only when broad categories were disaggregated into the more granular NHS classifications (for example, markedly elevated discoid lupus erythematosus prevalence in Black Caribbean but not Black African individuals, obscured within the aggregate “Black” category). This national, ethnicity-resolved map shows that rare-disease prevalence varies substantially across ethnic groups, with differences largely hidden within broad categories, and that recorded COVID-19 infection among people with RD varied across ethnic groups, with the highest rates observed in the ONS White and NHS White British groups. These findings provide a baseline to support earlier, fairer diagnosis and more targeted care.