The severity of infection with the SARS-CoV-2 B.1.1.7 lineage was investigated in COVID-19 patients hospitalised in Belgium

The interplay of host attributes, viral traits, and environmental factors influences COVID-19 pathogenesis. In hospitalized Belgian patients infected with SARS-CoV-2 variant B.1.1.7, we compare the severity of COVID-19 disease with people infected with previous variations.

By merging surveillance registries in Belgium, a causal approach was applied to evaluate the intensity of SARS-CoV-2 mutations. In terms of severe COVID-19 symptoms, ICU admission, and in-hospital mortality, infection with the SARS-CoV-2 B.1.1.7 strain ('exposed') was compared to people infected with previous strains ('unexposed'). To match the unexposed and exposed groups, the hospital and the ICU occupancy during the patient's hospital stay were used.

There was no difference between the unexposed and exposed groups in terms of severe COVID-19 infection or in-hospital deaths. The estimated standardized risk of being admitted to the ICU was considerably higher when infected with the B.1.1.7 variant. According to an age-stratified analysis, the SARS-CoV-2 variation B.1.1.7 was strongly associated with both serious COVID-19 progression and ICU hospitalization among the younger age group (65 years).

Our matched observational cohort analysis found no evidence of a higher risk of serious COVID-19 infection or death connected to B.1.1.7 infection in patients who had previously been admitted to the hospital. When infected with the B.1.1.7 strain, the likelihood of being admitted to the ICU was dramatically enhanced, particularly among the younger population. More extensive sequencing of specimens from COVID-19 patients in hospitals is suggested.