How much more transmissible is the new variant of coronavirus?

The new SARS-CoV-2 variant that appears for the first time in the south of England has a transmission advantage of 0.4 to 0.7 points greater in number of reproduction, also known as R0, compared to the strain initial, British researchers found.

This variant, called 202012/01, has a “substantial transmission advantage,” meaning that its reproduction numbers could range from 1.4 to 1.8, according to a multidisciplinary team based at Imperial College. London (ICL), which published its results on its website.

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

Volz and colleagues also noted a higher proportion of individuals under the age of 20 among reported cases of the variant compared to non-variant cases, which they dubbed “a change in age composition.” . They estimated that the R0 of the variant is 40% -80% higher than that of the wild-type virus.

For context in the U.S., previous research found that seasonal flu had an average reproduction number of 1.28, while the average reproduction number of the 1918 flu pandemic was 1.80.

This variant has already crossed the lake, with a Colorado man as the first documented case in the United States last week, although reports of the variant appeared in other states during the holidays, including California and Florida.

CDC officials told reporters Wednesday about the variant, noting that it appears unlikely to affect the effectiveness of the COVID-19 vaccine, although it may make certain treatments less effective, such as convalescent plasma. The agency says it expects more data on the variant soon.

A preliminary report from the UK Infectious Disease Mathematical Modeling Center on 23 December estimated that transmission could initially 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 substantially 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. It should be noted that they found a “high correlation” between S-gene target failure (SGTF) during COVID-19 PCR testing and variant frequency, meaning that S-gene failure could act as to biomarker to detect the variant in the community.

“We see a very clear visual association between the frequency of SGTF and the growth of the epidemic in almost all areas … which is reinforced by the empirical assessment of the specific factors of weekly growth [variant] and no[variant] case numbers, ”Volz and his colleagues wrote.

They noted a “small but significant” shift toward people under the age of 20 who were most affected by the variant, even after adjusting to several confusing ones. Any number of factors could explain this: an overall increase in the transmissibility of the variant, younger people more susceptible, or greater symptomatology with the variant.

The group warned that while additional research is needed, a variant with increased transmissibility indicates that public health measures may be needed to contain the virus.

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

But there are still no indications that the variant will withstand vaccine-mediated immunity or be more lethal, except to the extent that hospitals are more case-laden and therefore less able to provide high-quality care. level in all patients.