The coronavirus variant that was first detected in India, and is now known as the delta variant, is a \u2018variant of concern\u2019. Delta variant has been reported in 96 countries. There are a number of factors that are contributing to increased transmission around the world: people infected with it produce far more virus than those infected with the original version of SARS-CoV-2, making it very easy to spread.<\/p>\n\n\n\n
According to current estimates, the Delta variant could be more than twice as transmissible as the original strain of SARS-CoV-2. To find out why, epidemiologist Jing Lu at the Guangdong Provincial Center for Disease Control and Prevention in Guangzhou, China, and his colleagues tracked 62 people who were quarantined after exposure to COVID-19 and who were some of the first people in mainland China to become infected with the Delta strain.<\/p>\n\n\n\n
The researchers tested study participants\u2019 \u2018viral load\u2019 i.e a measure of the density of viral particles in the body. The viral load was tested every day throughout the course of infection to see how it changed over time. Researchers then compared participants\u2019 infection patterns with those of 63 people who contracted the original SARS-CoV-2 strain in 2020.<\/p>\n\n\n\n
In a preprint posted 12 July1, the researchers noted that the virus was first detectable in people with the Delta variant four days after exposure, compared with an average of six days among people with the original strain, potentially faster viral replication and greater infectiousness of Delta during early infection. Individuals infected with Delta also had viral loads up to 1,260 times higher than those in people infected with the original strain.<\/p>\n\n\n\n