The US Centers for Disease Control and Prevention (CDC) reported on July 29 that the COVID-19 Delta variant is as transmissible and contagious as chickenpox.

The said variant is also reported to be more severe than the other ones. The US CDC said that Delta is more transmissible than MERS & SARS, Ebola virus, Common cold, Seasonal flu & 1918 (“Spanish”) flu, and Smallpox.

The risk of infection with the Delta variant may be higher compared to the Alpha variant as written in the report, but only if prior infection occurs before or within 180 days.

Moreover, even if vaccines prevent less than 90% of severe disease, they may still be less effective at preventing infection or transmission so more breakthroughs and more community spread is expected despite vaccination.

CDC has published records regarding the spread of the variant in several countries as evidence of Delta’s risks. Canada and Scotland are reported to have higher odds of hospitalization while Singapore joins Canada in having higher odds of ICU admission and death. Singapore alone has higher odds of oxygen requirement and pneumonia. Meanwhile, India was reported to be of lower cycle threshold (Ct) values in Delta breakthrough cases compared to non-Delta breakthrough cases.

As of writing, the Delta variant has reached at least 98 countries as mentioned by Tedros Adhanom Gebreyesus of the World Health Organization in his biweekly press conference last July 2.

Source: https://fm.cnbc.com/applications/cnbc.com/resources/editorialfiles/2021/07/30/CDC_slides.pdf