Changes in symptomatology, reinfection, and transmissibility associated with the SARS-CoV-2 variant B.1.1.7: an ecological study
Study of positive COVID-19 tests reported by 36,920 COVID Symptom Study app users from Sept 28 to Dec 27, 2020, found no changes in reported symptoms or disease duration associated with B.1.1.7. and no evidence that the frequency of reinfections was higher for this variant.
Source:
The Lancet Public Health
SPS commentary:
Based on these current findings, researchers conclude that existing testing and surveillance infrastructure do not need to change specifically for the B.1.1.7 variant. In addition, given that there was no apparent increase in the reinfection rate, vaccines are likely to remain effective against the B.1.1.7 variant.
According to a commentary, this study adds to the consensus that B.1.1.7 has increased transmissibility, which has contributed in large part to the sharp rise in cases in the UK over the study period, though it reaches somewhat different conclusions about differences in symptoms than those of the UK Office for National Statistics, which reported that a higher proportion of individuals who tested positive for the B.1.1.7 variant had at least one symptom compared with those without the variant. Loss of taste and smell were also less common among individuals infected with B.1.1.7, whereas cough, sore throat, myalgia, and fatigue were more frequently reported (although absolute differences were small). It notes the researchers do acknowledge the limitations of using self-reported digital data for this type of analysis, and ecological analyses can be a limited statistical approach to establishing associations, particularly when both the dependent variable and independent variable might be subject to considerable measurement errors and such errors might themselves vary over time.
The commentary notes that fortunately, B.1.1.7 appears to be quite effectively combatted by existing vaccines (e.g. AstraZeneca ChAdOx1 nCoV-19 vaccine showed estimated 75% efficacy against B.1.1.7, compared with 84% against other lineages), although not all vaccines have released estimates of protection against the major variants of concern. It highlights the importance of monitoring the effectiveness of various vaccines against specific variants using coordinated post-approval infection studies. It concludes that although B.1.1.7 might have similar symptomatology to that of other lineages, the emergence of new variants is inevitable as long as SARS-CoV-2 transmission continues at scale.