How much more communicable is the new variant of Coronavirus?

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

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

Led by Erik Volz, PhD at ICL, 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 a change in R0.

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

For the US context, previous research found that seasonal flu had an average breeding number of 1.28, while the average breeding number for the 1918 flu pandemic was 1.80.

This variant has already crossed the lake, with a Colorado man being the first documented case in the US last week, although reports of the variant have surfaced in other states during the holiday, including California and Florida.

CDC officials informed reporters about the variant on Wednesday, noting that it appears 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 by the UK’s Center for Mathematical Modeling for Infectious Diseases on 23 December originally estimated that transmission could be at least 56% and up to 70% higher. They updated their findings on December 31, 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 epidemiological and genetic data, including 1,904 whole genomes from October and 5 December, with a genetic background of 48,128 genomes collected in the same period. Notably, they found a “high correlation” between the failure of the S gene (SGTF) during the COVID-19 PCR test and the frequency of the variant, which means that the failure of the S gene can 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 epidemic growth in almost all areas … which is reinforced by the empirical assessment of weekly and weekly growth factors specific to the area of [variant] and not-[variant] case numbers, “wrote Volz and his colleagues.

They noted a “small but significant” shift in the sense that individuals under the age of 20 are most affected by the variant, even after adjusting for various confounding factors. Any number of factors can be responsible for this: a general increase in the transmissibility of the variant, younger people being more susceptible or greater symptoms with the variant.

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

“Social distance measures will need to be stricter than they would otherwise be. A particular concern is whether it will be possible to maintain control over the transmission and, at the same time, allow schools to reopen, ”wrote the group.

But there is still no indication that the variant will resist vaccine-mediated immunity, or that it will be more lethal, except as hospitals become more burdened with cases and therefore less able to provide high-level care to everyone. patients.