The British variant is 45% extra contagious than the unique virus

The British variant is 45% more contagious than the original virus

From left to right: Prof. Ariel Munitz Dr. Dan Yamin Prof. Moti Gerlitz Photo credits: Tel Aviv University

A new study at Tel Aviv University found that the UK variant (referred to as: B.1.1.7) of COVID-19 is 45% more contagious than the original virus. The researchers drew on data from approximately 300,000 PCR tests for COVID-19 obtained from the COVID-19 testing laboratory that was set up in partnership with the Electra Group.

The new study was carried out by Prof. Ariel Munitz and Prof. Moti Gerlitz from the Department of Clinical Microbiology and Immunology at the Medical Faculty Sackler together with Dr. Dan Yamin and Ph.D. Student Matan Yechezkel from the Epidemic Modeling and Analysis Laboratory (LEMA) at the Department of Industrial Engineering at Tel Aviv University. The results of the study were published in the renowned journal Cell Reports Medicine.

The Electra-TAU laboratory was set up in March 2020 immediately after the first wave of the pandemic broke out in Israel. To date, hundreds of thousands of tests from across the country have been analyzed – from public drive-in testing facilities to programs that target specific populations – such as "Shield for Fathers and Mothers," which routinely performed vulnerable tests on hotspots like retirement homes.

Prof. Ariel Munitz explains: "We use a kit that tests three different viral genes. In the British variant, also known as B.1.1.7, one of these genes, the S-gene, was deleted by the mutation. As a result, we were able to we can track the spread of the variant without genetic sequencing. "

According to Prof. Munitz, the data from the laboratory show that the British variant spread very quickly: on December 24, 2020, only 5% of the positive results were attributed to the British variant. Just six weeks later, in January 2021, this variant was responsible for 90% of COVID-19 cases in Israel. The current figure is 99.5%.

"To explain this dramatic increase, we compared the R-number of the SARS-CoV-2 virus with the R-number of the British variant. In other words, we asked the question: how many people get the disease on average of each person who has either variant? We found the UK variant to be 45% – almost 1.5 times – more contagious. "

In the second phase of the study, the researchers segmented the infection by age group. The results showed that the tipping point for the population over 60 compared to other age groups was two weeks after the first vaccine shot by 50% of the population over 60 in Israel.

"Until January we saw a linear dependence of almost 100% between the different age groups in new cases per 1,000 people," says Dr. Dan Yamin. "Two weeks after 50% of those 60+ received their first dose of vaccine, that graph broke sharply and significantly. In January, a dramatic decrease in the number of new cases in the 60+ group was observed, along with a sustained increase in Rest of the population. Put simply, since more than 90% of those who have died from COVID-19 were over 60, we can say the vaccine saved hundreds of lives – even in the short term. "

The new study also shows that active surveillance of vulnerable populations works. "There is a threshold for determining whether a particular test is positive or negative for the virus – a lower value indicates a higher viral load," says Prof. Munitz. "When we compared the thresholds of the different genes in more than 60 residents of retirement homes with the values ​​measured in more than 60 people in the general population, we saw significantly higher values ​​in the retirement homes. This means that the viral load was in the retirement homes lower compared to the rest of the population.

Since retirement home residents are routinely tested, while other people are usually only tested when they are uncomfortable or have been in contact with someone who tests positive for the virus, we conclude that constant monitoring of populations at risk is a method that works. It is important to emphasize: the relatively low viral load was noted in retirement homes, although the British variant had already spread to all population groups. As a result, we show that nursing home surveillance, along with vaccination, prioritizing vulnerable populations, prevents disease and mortality. "

Dr. Yemin sums up: "Due to the overcrowded conditions, the large households and the age distribution of the Israeli population, the environment for the coronavirus to spread to Israel was more favorable compared to most Western countries. Our message to the world is if with our problematic Home If there is a significant decrease, other western countries can expect a dramatic decrease in severe post-vaccination cases of 50% of the elderly population despite the high level of contagion from the UK variant, along with targeted risk testing by Epicentres. "

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More information:
A. Munitz et al., BNT162b2 vaccination effectively prevents the rapid rise in SARS-CoV-2 variant B.1.1.7 in high-risk populations in Israel, Cell Reports Medicine (2021). DOI: 10.1016 / j.xcrm.2021.100264

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Tel Aviv University

The UK variant is 45% more contagious than the original virus (2021, April 20th)
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