Infectious Delta variant (B.1.617.2) first discovered in India and now making rounds across the countries, particularly the UK, spreads fast in a household setting, according to a study by Public Health England, a UK Government health organisation, thus decoding why several households have reported multiple cases of Covid-19 infection this time as compared to mostly single cases in families in the earlier wave.
The report noted that the Delta variant is fueling the Covid-19 second wave in many parts of India including south Indian states and spurt in cases in some countries like the UK. However, the report said that those vaccinated do not show severity of infections, thus calling for an increase in global vaccinations.
While other variants mostly infect one person in a household, the Delta infects more than one. This explains why several members in many families were down with Covid-19 this time. The Public Health England has compared the transmission rate of the Delta variant in a household setting with that of the Alpha variant (B.1.1.7), which is also a variant of concern. The Alpha variant was first discovered in the UK.
“Overall, we found increased household transmission of Covid-19 associated with B.1.617.2 compared to B.1.1.7. These findings show households are important settings for rapid transmission of the lineage B.1.617.2. With household settings being an important factor in wider community spread, strategies to prevent transmission in these settings are vital to control the Covid-19 pandemic,” the PHE study said.
It noted that there is a 64 percent increase in the odds of household transmission associated with infection with B.1.617.2 variant compared to B.1.1.7. “This study provides early real-world evidence of the effect B.1.617.2 variant on household transmission. The findings support existing evidence that B.1.617.2 has a substantially increased transmissibility advantage over the B.1.1.7 variant,” the PHE researchers said.
This study also found evidence of increased household transmission among households with an index case of Asian ethnicity,” the researchers added. They said households are high risk settings for transmission of Covid-19 and are an important factor in wider community spread. “By assessing the extent to which B.1.617.2 results in onward transmission to household members compared to B.1.1.7, we can assess the relative transmissibility of this variant, and provide information vital to the national and international pandemic response,” they added.