What You Need To Know About the COVID Delta Variant

August 6, 2021

The Delta variant is the current genetic variant of coronavirus predominating the nation and proving to be more contagious, with a faster onset of symptoms, than other strains of the SARS-CoV-2. According to the Center for Disease Control and Prevention (CDC), the Delta variant currently accounts for more than 80% of new cases in the United States. Health experts say it is not unusual for a new strain of a virus to be more contagious because it often becomes much more efficiently transmitted as it mutates.

What are Variants?

As the virus transmits from person to person, genetic variants of coronavirus continue to emerge and circulate the world. Since November 2020, the CDC has regularly received SARS-CoV-2 samples from state health departments and other public health agencies for sequencing, further characterization, and evaluation. Viral mutations and variants in the United States are routinely monitored through sequence-based surveillance, laboratory studies, and epidemiological investigations.

A US government SARS-CoV-2 Interagency Group (SIG) developed the Variant Classification scheme below that defines three classes of SARS-CoV-2 variants:

  1. Variant of Interest
  2. Variant of Concern
  3. Variant of High Consequence

The B.1.1.7 (Alpha) from the United Kingdom, B.1.351 (Beta) from South Africa, B.1.617.2 (Delta) from India, and P.1 (Gamma) from Japan and Brazil are variants of concern currently circulating in the United States. As of now, no variants of high consequence have been identified in the United States.

Why is Delta More Transmissible?

Researchers at the Guangdong Provincial Center for Disease Control and Prevention noted that the amount of virus produced in infected individuals, the viral load, is up to 1,000 times higher with the delta variant. A preprint study also suggests the average time from infection to being able to readily detect the virus was about four days, compared to about six days during the original outbreak. The delta variant appears to be much better at binding to cell receptors than the original strain, which means it can replicate much faster and be detected earlier.

Unlike previous variants, the Delta variant has proven to be transmitted by both vaccinated and unvaccinated individuals. New data from the CDC published on July 30, 2021, shows that the viral load measured in breakthrough cases among those fully vaccinated is similar to the levels detected among unvaccinated individuals. Although vaccination does not prevent transmission of the Delta variant, it does prevent the severity of symptoms, with the majority of vaccinated individuals showing minimal symptoms or no symptoms at all. According to CDC data, more than 99.99% of people fully vaccinated against Covid-19 have not had a breakthrough case resulting in hospitalization or death.

Download the Checklist: 10 OSHA Recommendations for COVID-19 Mitigation Policies

What Groups are at Risk?

Unvaccinated individuals continue to be at the highest risk of infection, with the high transmissibility of the delta variant observed in communities with low vaccination rates. CDC estimates the unvaccinated individual make up 97% of hospital COVID-19 admissions in July 2021. Unvaccinated individuals are encouraged to take steps to protect themselves against COVID-19 by wearing a mask, physical distancing, and avoiding crowds and areas with poor ventilation.

According to the latest CDC guidance updated on July 27, 2021, fully vaccinated individuals can proceed in activities the same as before with a few precautions. To maximize protection from the Delta variant and prevent possible transmission, vaccinated individuals are encouraged to wear a mask indoors in public when in areas of substantial or high community transmission. Community transmission levels are updated daily and tracked on the Center for Disease Control COVID-19 Integrated County View. Regardless of the level of community transmissions, prevention strategies are most critical for those with weakened immune systems or underlying medical conditions which pose an increased risk for severe disease, especially if unvaccinated.

Breakthrough cases for vaccinated people are rare but do occur. The CDC changed their isolation and testing recommendations on July 27, 2021, for fully vaccinated people to address these cases.

  • Fully vaccinated people experiencing COVID-19 symptoms are asked to get tested.
  • If you are directly exposed to someone who tests positive for COVID-19 or you suspect may have COVID-19, you are asked to get tested 3-5 days after exposure and wear a mask for 14 days or until you test negative for the virus.
  • If you test positive for COVID-19, the CDC says you need to isolate.


Vaccination is the primary prevention strategy to protect against COVID-19. Whether or not you are vaccinated, it’s also essential to follow updated CDC prevention guidelines and local regulations concerning prevention strategies. Layered approaches to prevent infection, such a masking, physical distancing, and increased ventilation in crowded areas, combine to form added protection when vaccination levels are not sufficient. As long as the virus continues to be transmitted across the globe, new strains will continue to develop and impact communities. The most important thing you can do to protect yourself and your community from variants is to get fully vaccinated.

If you have any questions, you can click here to schedule a customized consultation with Shari Solomon, President of CleanHealth Environmental. In addition, we invite you to download our checklist with 10 OSHA recommendations to help mitigate the transmission of COVID-19 at your workplace.

Download the Checklist: 10 OSHA Recommendations for COVID-19 Mitigation Policies