How much more transmissible is the new Coronavirus variant?

The new SARS-CoV-2 variant, which appears for the first time in the South of England, has a transfer advantage of 0.4 to 0.7 points higher than the reproduction number, also known as R0, compared to the initial voltage, British researchers found.

This variant, called 202012/01, has a “substantial transfer advantage”, which means that its reproduction numbers can range from 1.4 to 1.8, according to a multidisciplinary team based at Imperial College London (ICL), which shares their findings. about the school’s publication. website.

Led by ICL’s Erik Volz, PhD, the team found a “large and statistically significant imbalance” in regions where the incidence of the variant increased and the incidence of the non-variant decreased, and vice versa, which would indicate on a change in R0.

Volz and colleagues also noted that a greater proportion of individuals were younger than 20 among the cases of the variant versus non-cases, and this calls for a shift in the composition of the age ‘. They estimate that the variant’s R0 is 40% -80% higher than for the wild-type virus.

Regarding the context in the US, previous research found that seasonal flu had a median reproduction number of 1.28, while the median reproduction number for the 1918 flu pandemic was 1.80.

This variant has already traveled across the dam, with a Colorado man as the first documented case in the US last week, although reports of the variant surfaced in other states during the holidays, including California and Florida.

CDC officials informed reporters on Wednesday about the variant, pointing out that it is unlikely to affect COVID-19 vaccine efficacy, although it may make certain treatments less effective, such as recovery plasma. The agency says it expects more data on the variant soon.

A preliminary report from the UK’s Center for Mathematical Modeling of Infectious Diseases on 23 December may initially estimate that transmission would be at least 56% and up to 70% higher. They updated their findings on 31 December, noting that the frequency of the variant “has grown significantly in all regions of England”, with a frequency of 50% or more in all regions of the national health system.

The Imperial College group examined both epidemiological and genetic data, including 1,904 whole genomes from October and December 5 with a genetic background of 48,128 genomes collected during the same period. In particular, they found a ‘high correlation’ between S-gene target failure (SGTF) during COVID-19 PCR testing and the frequency of the variant, which means that the failure of the S-gene target as a biomarker can serves to locate the variant in the community.

‘We see a very clear visual relationship between SGTF frequency and epidemic growth in almost all areas … which is reinforced by empirical assessment of the area-specific week on week factors of [variant] and non-[variant] case numbers, ”Volz and colleagues wrote.

They noted that a “small but significant” shift toward individuals under the age of 20 is more affected by the variant, even after being adapted for multiple confusion. A number of factors may be responsible for this: an overall increase in transmissibility of the variant, younger people being more susceptible, or greater symptomatology with the variant.

The group warned that although further investigation is needed, a variant with increased transmissibility suggests that increased public health measures may be needed to contain the virus.

“Social distance measures will have to be stricter than they would otherwise have been. A particular concern is whether it will be possible to maintain control over the transfer while schools can reopen,” the group wrote.

But there is still no indication that the variant will resist the vaccine-mediated immunity, or that it is more lethal, except to the extent that hospitals are more overloaded with cases and therefore less able to provide high-level care. to offer each patient.