New variant does not increase reinfection risk, disease severity, deaths

Preliminary results from a cohort study show no statistically significant difference in hospitalisation, 28-day case fatality and reinfection between the new variant and wild-type comparator cases.

Preliminary results from a cohort study show no statistically significant difference in hospitalisation and 28-day case fatality between cases with the new variant (VOC 201212/01) and wild-type comparator cases. There was also no significant difference in the likelihood of reinfection between variant cases and the comparator group, says a second technical briefing report by the Public Health England.

The new variant was first identified in Kent and Greater London in end-September.

The preliminary assessment of outcomes of hospitalisation and case fatality caused by the new variant was performed by using a matched cohort study. In this, 1,769 genome sequenced variant cases were matched with the same number of cases which are distinctly different from the new variant. The median age of variant cases was 36 years and 35 for the wild-type cases. Over 51% of both the variant cases wild-type comparator cases were female.

Fewer variant cases (16 cases) were admitted to hospital compared to wild-type comparator cases (26 cases) but the difference is not significant, the report says. For case fatality assessment, 1,340 people belonging to each group who have completed 28 days since the specimen date were compared. The study found  that 12 of 1,340 (0.89%) people infected with the new variant died within 28 days compared with 10 of 1,360 (0.73%) people infected with virus not belonging to the new variant. The difference in case fatality between the two groups is “not significant”, the report says.  

No increased reinfection risk

Scientists also studied whether the new variant caused increased reinfection rates. A possible case of reinfection was considered if a PCR test was positive before 90 days of a previous infection with SARS-COV-2 virus. While only two reinfections were caused by the new variant, there were three reinfections in the other group.

Variant renamed

Following risk assessment, the nomenclature of the new variant has been changed. While the variant was earlier called Variant Under Investigation (VOI), it is now known redesignated as Variant of Concern (VOC). As a result, the new variant, which was earlier called VUI 202012/01 on detection, has been re-designated on December 18 as VOC 202012/01.

Published in The Hindu on December 29, 2020