Advance with MUSC Health

The COVID Delta Variant and Here We Go Again

Joseph Gerald (Jerry) Reves, M.D.
August 24, 2021
A graphic of miniature people amongst giant purple Coronavirus balls.

As the Delta variant of COVID-19 rages across South Carolina, sickening younger people and once again packing hospital ICUs, some of our leaders say we have nothing to worry about.

Actually, we have a great deal to worry about if we want to remain healthy and send our children back to school safely. Roughly half our fellow citizens refuse to get vaccinated. Moreover, the fact that children are not yet eligible to receive the vaccine has led to serious cases in children under 12.

Good public health requires that everyone get vaccinated. We have known this since the initial outbreak of COVID-19.

The Delta Variant - What We Know

The original version of the COVID-19 virus, now called the Alpha strain, spread worldwide, infecting hundreds of millions of people and killing millions.

If the Delta variant proves more lethal than the Alpha strain, then we are headed for more devastation in our state. South Carolina's case mortality rate for the Alpha strain is about 1.6%, meaning nearly two of every 100 people who test positive will die. That is a much higher mortality rate than the seasonal flu.

Viruses are small, but they're "smart" even though they don't have a brain like we do.

They live in host animals. Counter-intuitively, their mission is to multiply and kill their host, but they also die when the host dies unless they can spread to a new host. This is where the virus has "learned" to mutate, or change into a new strain.

Not only can that change increase the virus' ability to spread, but the new virus strain can overcome a host&'s defenses, thus ensuring its survival. The great fear is that a new strain can change enough to be resistant to the vaccine.

The Delta variant is now the predominant strain of the new cases of COVID in South Carolina and is approaching that level throughout the country. The Delta variant of COVID-19 is 40 to 60% more infectious that the Alpha strain. (See Figure 2). This means contracting the virus is much easier. It also can be spread to vaccinated people who can themselves spread the virus, but for a shorter period of time than unvaccinated people.

Fortunately, those who have been vaccinated are far less likely to get sick or die from the Delta strain, compared to the unvaccinated. In addition to spreading more easily, the Delta variant is making unvaccinated people sick. Most of those who are hospitalized and dying are unvaccinated. The victims are also younger than in the earlier peaks of the Alpha strain.

What is the Strategy?

Why nearly half of South Carolina's eligible population has chosen not to get vaccinated is a public health failure. Everyone eligible should get vaccinated. Plainly stated, the best strategy to end the pandemic is to achieve herd immunity. That can be done only if people get vaccinated or develop natural immunity after acquiring the disease.

Given our state's low vaccination rate, if we're concerned about our health and that of others, we must all, regardless of our vaccination status, again observe the rules that almost got rid of the virus.

  • Wear masks indoors in public places.
  • Keep our physical distance from others - 6 feet is the ideal.
  • Wash our hands frequently.

Figure 1 shows the weekly running average of new COVID-19 cases in South Carolina. This graph can be reproduced in those states that have low vaccination rates.

A graph that represents new COVID cases in South Carolina.
Figure 1. The dark blue line shows the average weekly number of new COVID-19 recorded in S.C. The light blue lines go between individual day new case numbers. The 7-day average as of this writing is similar to December 7, 2020. Lowest 7-day average was June 22, 2021 at 75. The current 7-day average is 2,452.
Source: The New York Times
A graphic from the CDC 2 demonstrating a major difference between the Delta variant and its cousin the original Alpha COVID-19 virus, which is its infectivity.
Figure 2 A major difference between the Delta variant and its cousin the original Alpha COVID-19 virus is its infectivity. From: Delta Variant: What We Know About the Science | CDC