Nine in ten of these patients had not had the updated vaccine

Design

Retrospective cohort study using national collaborative electronic health record data with mixed-effects logistic regression

Population

60,980 adults with autoimmune rheumatic conditions and incident COVID-19, December 2020 to August 2024, median age 62

Primary outcome

COVID-related hospitalisation by vaccination status

Effect

Adjusted OR vs unvaccinated: initial series 0.59 (95% CI 0.56-0.63), booster 0.29 (0.27-0.31), updated 2023-2024 vaccine 0.31 (0.28-0.34); absolute risk reduction 5.6% for booster or updated over initial series alone

Sixty thousand nine hundred and eighty adults with autoimmune rheumatic conditions and incident COVID-19 between December 2020 and August 2024 were analysed from a national research collaborative, with mixed-effects logistic regression adjusting for demographics, clinical risk, social vulnerability and medications. Median age was 62 and 76% were women.

The dose-response is clean. Against no vaccination, adjusted odds of COVID-related hospitalisation were 0.59 (95% CI 0.56-0.63) after the initial series, 0.29 (0.27-0.31) after a booster and 0.31 (0.28-0.34) after the updated 2023-2024 vaccine. Comparing those who stopped at the initial series with those who went on to a booster or updated dose, the absolute risk reduction was 5.6%.

The number that should prompt action is elsewhere in the paper: only 6,336 of 60,980 patients - 10% - had received the updated vaccine. In a population defined by immunosuppression and by regular specialist contact, that is a coverage failure rather than an evidence gap. Rheumatology clinics see these patients several times a year and are well placed to ask, and mostly do not, because vaccination is assumed to belong to primary care. An absolute risk reduction of 5.6% for hospitalisation is a number worth quoting to a hesitant patient, and it is larger than the benefit of several drugs these clinics spend far longer discussing.

• Ask about COVID vaccination status at every review, as a clinic responsibility rather than primary care's
• Quote the absolute figure - about a 5.6% lower chance of hospitalisation going beyond the initial series
• Time vaccination around rituximab and other B-cell depleting therapy rather than skipping it
• The booster and updated vaccine performed similarly; the gap that matters is between initial series and anything beyond it
• Record the conversation, including declines, so the next clinician is not starting from nothing

Why it matters

The gap here is not in the evidence for vaccination, it is in who takes responsibility for asking.

Don't overread it

Observational - people who seek boosters differ from those who do not in ways adjustment cannot fully capture.

The statistics, in plain English

The near-identical odds ratios for boosted (0.29) and updated (0.31) vaccination are worth noting: on these data the updated formulation is not clearly better than an older booster, and the benefit is in having had more than the initial series at all. The odds ratios come from observational data adjusted for measured confounders, and the largest unmeasured one is health-seeking behaviour - people who get boosted differ from people who do not in ways no adjustment fully captures, which will exaggerate the apparent benefit. The absolute risk reduction of 5.6% is the more useful figure for a consultation, because an odds ratio of 0.29 sounds like a 71% reduction and is not.

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