SARS CoV-2 Delta Variant: What To Know

At a Glance

Viruses mutate due to their rapid reproduction and the ease with which they can exchange genetic material. This has held true with the COVID-19 virus, most recently with the variant B.1.617.2, better known as the “Delta variant,” considered a variant of concern.

What Is A Variant of Concern?

As defined by the CDC, a variant of concern is “A variant for which there is evidence of an increase in transmissibility, more severe disease (e.g.,  increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.”  CDC currently lists the alpha, beta, gamma, and delta variants as variants of concern.

Why Is Delta a Variant of Concern?

As of this writing, the primary concern is that the Delta variant appears to be more transmissible. Data from the UK has indicated that the variant has an estimated 60% higher risk of household transmission, which is more infectious than the original virus and the previously dominant Alpha variant.

Testing data shows that Delta variant is well on its way to becoming the most common form of COVID-19 in several parts of the world, including the United States where experts predict it will become the dominant strain within 2-3 weeks. There is currently no indication that it causes more hospitalizations or fatalities than other variants. However, as it’s more likely to be transmitted, it will increase the overall number of cases among those vulnerable, leading to more hospitalizations and deaths. There may also be a rise in so-called “breakthrough” cases, where a vaccinated person becomes infected.

Who Is Most At Risk From The Delta Variant?

The unvaccinated have the most to be concerned about with Delta. While hospitalization and death do not seem to be higher according to available data, the increased likelihood of transmission raises the overall chances this group will be infected and run the risk of negative outcomes. Those with only one shot in a two-shot series, such as Pfizer or Moderna vaccines, are also at higher risk.

Are Vaccines Less Effective Against The Delta Variant?

More data is needed, but what’s been collected by British health authorities indicates vaccines remain highly protective against COVID-19. So far, the data has found that when the full course of vaccination is complete, the Pfizer-BioNTech vaccine is 96% effective against hospitalization by the Delta variant, and that Oxford-AstraZenica is 92% effective.

Currently, it’s not clear how effective any vaccine is at preventing death, although the high effectiveness against hospitalization points to similarly high ability to limit mortality.

Also unclear is whether effectiveness will remain high for asymptomatic infections, where a person may have no outward symptoms, or an infection with only minor symptoms, which may be mistaken for a common cold or flu without testing. This may raise the transmission rate still further.

What Can I Do If I’m Concerned About The Delta Variant?

  • Get vaccinated if it’s a possibility for you. Vaccines are the most effective way to protect yourself and to limit the possibility of infecting others.
  • If you display symptoms of any respiratory infection, even if you’re vaccinated, get tested for COVID-19 and stay home.
  • Wear a mask if you’re unvaccinated or partially vaccinated.  Even if you’re fully vaccinated, consider wearing a mask if you’ll be indoors with people you don’t know. Second to vaccines, masks are next in line in importance for preventing virus transmission.
  • Stick to social distancing protocols, and stay six feet away from others where possible.
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