How much more transmissible is the new variant of coronavirus?

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

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

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

Volz and colleagues also noted a higher share of individuals under the age of 20 in the reported cases of variant cases than in non-variant cases, calling this “a change in age composition.” They estimated that the R0 variant is 40% -80% higher than for the wild-type virus.

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

This variant has already traveled across the pond, with a man from Colorado as the first case documented in the US 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 is unlikely to impact the effectiveness of the COVID-19 vaccine, although it may make some treatments less effective, such as convalescent plasma. The agency says it expects more data on the variant soon.

A preliminary report from the Center for Mathematical Modeling of Infectious Diseases in the UK on 23 December, the initially estimated transmission may be at least 56% and up to 70% higher. They updated their findings on 31 December, noting that the frequency of the variant “increased substantially in all regions of England”, with a frequency of 50% or higher 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 over the same period. In particular, they found a “high correlation” between S gene target failure (SGTF) during COVID-19 PCR testing and variant frequency, meaning that S gene target failure could act as a biomarker to detect the variant in the community.

“We see a very clear visual association between the frequency of SGTF and the increase in the epidemic in almost all areas … which is strengthened by the empirical assessment of weekly growth factors [variant] and non-[variant] case numbers, “Volz and his colleagues wrote.

They noticed a “small but significant” change in people under the age of 20, who are more affected by the variant, even after adjusting for more confusing. Any number of factors could explain this: an overall increase in the transmissibility of the variant, the younger people being more susceptible or a greater symptomatology with the variant.

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

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

But there is still no indication that the variant will withstand vaccine-mediated immunity or be more lethal, unless hospitals become more overloaded with cases and thus less able to provide high-level care to each patient.