Delta Variant as Infectious as Chickenpox: What to Know Now

09/09/21 By Dana Szymkowiak

According to an internal document from the CDC, the Delta variant surging across the United States is more transmissible than the viruses that cause MERS, SARS, Ebola, the common cold, the seasonal flu, and smallpox, and it is as contagious as chickenpox. This makes Delta the fastest and fittest version of the coronavirus we’ve seen.

The document also suggests the Delta variant may cause more severe illness. However, there isn’t enough data to say that’s the case.

Furthermore, people who get the Delta variant reportedly have higher viral loads than those with the original strain. Researchers are currently looking into how viral loads in vaccinated people translate to how transmissible it is.

What we know about how the Delta variant spreads

Scientists believe the Delta variant is spreading up to 60% faster than the Alpha variant, which was believed to spread 50% faster than the original strain. 

There was essentially no 2020-2021 flu season, thanks to all the precautions we took to prevent COVID-19. But, despite the precautions, the Alpha and Delta variants continued to be contracted, affecting millions of people. This data leads scientists to believe that Delta is more contagious than the flu and is on par with measles or chickenpox.

A vastly more transmissible virus

To determine how easily an infectious disease such as COVID-19 spreads, epidemiologists use a metric called the basic reproductive number or R0 (pronounced “R naught”). R0 is the average number of susceptible people that each infected person is expected to infect. 

The CDC estimates that people infected with Delta pass the virus to between five and 9.5 people, much higher than the original virus (R0 between 2.3 and 2.7), and the Alpha variant (R0 between four and five). As a result, Delta can be as infectious as chicken pox, which has an R0 between 9 and 10.

A higher viral load

Chinese researchers found that people infected with Delta had about 1,000 times the viral load in their respiratory tract compared to those infected with the original strain. This variant also makes people contagious in about four days, rather than six, as with other variants.

Molecular details

Delta’s efficiency comes down to the molecular details. The Delta variant carries multiple mutations, including within the spike protein, which it uses to latch onto and enter cells. Scientists are still trying to understand Delta’s unique combination of genetic mutations. 

Stay safe as the Delta variant spreads

Hand Sanitizer

Hand sanitizer has become a staple item around facilities since the onset of COVID-19. It’s important to stay stocked up on your supply so that you don’t run out as the Delta variant continues to spread. Safetec’s instant hand sanitizer formulations kill up to 99.99% of widespread germs and contain 66.5% ethyl alcohol, above the CDC’s recommended amount.

Face Masks

The latest guidance by the Centers for Disease Control and Prevention (CDC) recommends the use of masks again for vaccinated people in high transmission areas. Safetec’s EZ-Personal Protection Kit provides complete exposure protection containing a pair of vinyl gloves, fluid-resistant gown, combo mask/safety shield, and p.a.w.s.® Antimicrobial Hand Wipe.


As COVID-19 cases climb again, it’s time to stock up on disinfecting products. Maintaining frequent cleaning and disinfecting of facilities and stocking supplies remains a priority. On the EPA List N: Disinfectants for use against SARS-CoV-2 (Covid-19), SaniZide Pro 1, and SaniZide Plus are EPA Registered ready-to-use surface disinfectant sprays and wipes.