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A comment from the authors of the work (not third-party comments) which has just been published in the latest batch of SAGE documents. The authors are all members of the JUNIPER consortium (https://maths.org/juniper/).
The authors of the paper said:
“The dominant variant currently causing most COVID-19 cases in the UK is B.1.1.7 and this shows S-gene negativity on testing. A number of the more well-known variants show S-gene positivity on testing, but recent sequencing results of S-gene positive COVID-19 cases have predominantly been the B.1.617.2 variant.
“This paper focuses on detections of S-gene positivity as a proxy for B.1.617.2 cases, as these data are available in a more timely manner than sequencing. This approach gives the most rapid view on a fine scale, but with the drawback of some uncertainty as the precise variant has not been confirmed for the latest cases until genetic sequencing is completed.
“S-gene positive cases have been exponentially increasing since the end of March, compared with an overall decline in all cases of COVID-19 and a decline in S-gene negative cases. In particular, S-gene positive variants are growing quickly in a number of locations while S-gene negatives are declining in the same areas. Hence in these areas at least, S-gene positive variants have a large growth advantage (more than 1.4 times faster than S-gene negative).
“While this would be consistent with B.1.617.2 being more transmissible than B.1.1.7, this is not a certainty: S-gene positive cases may include other variants, and this growth is so far observed in only a few locations.
“Further investigation is recommended, particularly to better understand the patterns in areas with growing S-gene positive cases, and whether these S-gene positive cases have been vaccinated or previously infected. Testing coverage that reveals S-gene type varies across the country, so establishment and growth of variants may not be detected in some parts of England.
“This paper to SAGE represented preliminary results, as best available at the time, and focussed on areas with the most concerning outbreaks. There are many potential biases that were not possible to be fully controlled for. We described the known biases in the limitations section in the document. Given the importance of these results, these preliminary findings were shared with SPI-M and SAGE. We hoped that by sharing this preliminary analysis, it would help inform effective public health interventions to control growth, in the areas of most concern. Work is ongoing to update our estimates as the situation develops.”
All our previous output on this subject can be seen at this weblink:
www.sciencemediacentre.org/tag/covid-19
Declared interests
None received.