3 Things To Know About the Delta Variant

Vlad Khaustovich
3 min readAug 7, 2021


Photo by Viktor Forgacs on Unsplash

In 2021, people began to feel some optimism that the coronavirus pandemic could finally come to an end with the rollout of COVID-19 vaccines. However, there was still the threat that mutations of the virus could bring it back. On July 27, 2021, the Centers for Disease Control and Prevention (CDC) has released updated guidance, emphasizing the need to increase vaccination coverage due to concerning developments related to the Delta variant. The Delta variant originated in India in December 2020, spreading rapidly across the country and Great Britain before reaching the US recently. According to the CDC, the Delta variant accounts for 83% of all coronavirus cases in the US, and this percentage is forecast to increase to 93%.

What is the Delta variant?

The Delta variant represents one of the mutations, which is more dangerous compared with other variants. From time to time, a virus changes in a way that helps it survive and reproduce. Since March 2020, there were multiple COVID-19 mutations. To illustrate different levels of the threat posed by such variants, the CDC has developed a variant classification scheme, which includes the variant of interest, the variant of concern and the variant of high consequence. Variants of interest are the lowest risk variants that typically spread locally. Variants of high consequence are the highest risk variants that significantly reduce the effectiveness of medical intervention and prevention measures. Luckily, there are currently no variants that rise to the level of high consequence. The Delta variant belongs to the variant of concern group, which exhibits higher transmissibility, more severe disease and a significant reduction in neutralization by antibodies generated during previous infection or vaccination.

How contagious is the Delta variant?

According to the CDC, the Delta variant is almost twice as contagious as previous variants. The organization states that the Delta variant might cause more severe illnesses in unvaccinated individuals, referring to two different studies, including a study from Scotland, which indicated that patients infected with the Delta variant were more likely to be hospitalized than patients with the original virus or other variants. A recent study by Public Health England also showed that the Delta variant is more resistant to vaccines. For patients receiving the first shot of the Pfizer-BioNTech mRNA vaccine, effectiveness was 47.5% for the alpha variant but only 35.6% against the delta variant. After two doses, effectiveness grew, although it was still lower for people infected with the Delta variant. Despite Delta variant’s higher spread and better resistance to vaccines, more research is needed to determine the level of threat it represents.

How to protect yourself against the Delta variant?

A coronavirus vaccine remains the best method to protect yourself against the Delta variant. The greatest risk of the Delta variant transmission is among unvaccinated people who are more likely to contract and transmit the disease, according to the CDC. Therefore, the best way to protect against the Delta variant is to take one of the COVID-19 vaccines. However, even vaccinated individuals are at risk of getting infected with the Delta variant, although such risk is lower and vaccinated people appear to be infectious for a shorter period. Thus, encouraging everyone to wear masks in public places remains an effective method to keep everyone safe.