Laura Boekel and colleagues pooled data from two large ongoing prospective cohort studies and analysed post-vaccination serum samples for evidence of breakthrough infection. They report that the incidence of breakthrough infections was comparable between patients taking immunosuppressants and controls. Hospitalization was required in similar proportions in both groups – and in general hospitalized cases were older, and had more comorbidities compared with non-hospitalized cases.
Hospitalization rates were significantly higher among patients treated with anti-CD20 therapy compared to any other immunosuppressant. Although anti-CD20 therapy might increase susceptibility to severe COVID-19 breakthrough infections, the authors argue that traditional risk factors continue to make a critical contribution. With this in mind, most patients with IRDs should not necessarily be seen as a risk group for severe COVID-19, and integrating other risk factors should become standard practice when discussing treatment options, vaccination, and adherence to infection prevention measures with patients.
Breakthrough infection data was also presented by Dr Rebecca Hasseli, with a focus on the German COVID-19-IRD registry as of 31st January 2022. In total, 271 cases of breakthrough infections were reported, of whom 91% had received two doses of vaccines, and 9% patients three doses, and the median time from last vaccine dose to infection was 148 days.
Although the rate of comorbidities and median age were higher in triple-vaccinated patients, infected patients showed a lower rate of hospitalization, COVID-19 related complications, need of oxygen treatment, or death.
These results support the general recommendations to reduce the risk of severe COVID-19 disease by administering three doses of vaccine, especially in patients with older age, presence of comorbidities, and those on immunomodulatory treatment.