New Study Explains Virulence of New Variants


Day 336: Stay Safe Minnesota

According to a new study, the high transmission rate of B.1.1.7 variant could be due to the amount of time it lingers inside an infected person.

The new COVID variant from the UK, known as B.1.1.7, is reportedly is expected to be the most dominant coronavirus in the US and around the globe. According to Centers for Disease Control and Prevention (CDC), 1661 new cases of the B.1.1.7 variant is reported from 44 states (as of Feb 21). The variant is now doubling every 10 days in US, according to a new study.

Increased Variant Spread Expected

In the LifeScience, Yasemin Saplakoglu writes that the B.1.1.7. is growing exponentially in prevalence in the US, “making up around 2% of currently circulating strains as of January and likely doubled to 4% of circulating strains 10 days later, and 10 days after that, will double to 8%, then 16% and so on. By March it will likely be the most common variant in the country”.

The authors of a new preprint study posted on medRxiv on Feb. 7 and not yet peer-reviewed, wrote:

“The variant, which seems to be about 40% to 70% more transmissible than previous forms of SARS-CoV-2, the virus causing COVID-19, has ‘gained a strong foothold across the world’.”

According to the study, the B.1.1.7 variant is still at a “relatively low frequency,” in the U.S., it is 35% to 45% more transmissible than earlier forms of the virus.

Understanding the Virulence of New Variants

In the Washington Post, Erin Cunnigham highlights findings of two new studies that that sheds light in understanding virulence of the new COVID variants.

Researchers from the Harvard in a recent study posted in Harvard website found that high transmission rate of B.1.1.7 variant could be “due to the amount of time it lingers inside an infected person”. The researchers found that “the B.1.1.7 variant’s average infection period was 13.3 days, up from the 8.2 days associated with the original strain”.

If borne out by additional data, a longer isolation period than the currently recommended 10 days after symptom onset may be needed to effectively interrupt secondary infections by this variant.

A New Harvard Study (source: Washington Post)

In an another study posted to the bioRxiv preprint server last week, researchers from China “examined how variants first identified in Brazil and South Africa interacted with antibodies and infected cells”.

Both the Brazil and South Africa variants are known to contain the E484K mutation on the virus’s spike protein, which breaks into cells and ultimately allows it to evade the body’s immune defenses.

According to the study reported from China, “after the spike protein enters the cell, it has ‘more favorable’ electric charges that strengthen the bond to its target. Those charges created by the E484K mutation, the authors said, help stave off antibodies that were effective in neutralizing previous versions of the virus”.

Studies are underway to better understand the higher virulence of variants and design vaccines to minimize their further spread.

COVID-19 Vaccination Watch

According to the US Centers for Disease Control and Prevention (CDC) COVID vaccination tracker page (as of Feb 26, 9 a.m.) 94,300,910 doses have been distributed and 70,454,064 doses administered. According MDH COVID-19 Response vaccine data (as of Feb 24) a total of 1,212,816 doses of Covid-19 (Pfizer & Moderna) vaccines have been administered in Minnesota. According to the MDH latest tally (as of Feb 26) the confirmed COVID-19 cases in Minnesota are 482,978 (out of 7,289,410 tested) with 6,462 deaths.