Delta variant

Delta Variant: What We Know About the Strain That's Causing a Surge in COVID Cases

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Public health officials are sounding alarm bells throughout the United States, as the delta variant of the COVID-19 virus has led to a massive surge in cases in recent weeks.

According to research from Johns Hopkins University, the average number of daily COVID cases in the U.S. has gone up 66% in just the last week, and is up 145% from two weeks ago. Hospitalizations are also up during that time, leading officials to warn of potential mitigations in some locations.

So what exactly is the delta variant? What makes it different from previous strains of the COVID-19 virus? Do vaccines protect you against it?

Here is what we know about the delta variant so far.

What Makes the Delta Variant Different Than Previous Strains?

The biggest difference between the delta variant and other strains is that it is significantly more contagious. According to scientists at Yale Medicine, the delta variant is 50% more contagious than the alpha variant, which originated in the United Kingdom and is the most common strain of the virus seen in Illinois.

The alpha variant was 50% more contagious than the original strain of COVID-19, meaning that the number of people that could potentially be infected by each COVID-positive individual is significantly higher. According to experts, the average COVID-positive individual, in a completely unmitigated environment without masks or other barriers, would infect an average of 2.5 people.

The same person, if they had the delta variant of the disease, would infect four people or more, according to researchers.

The more contagious a strain of COVID is, the more quickly it will spread, as evidenced by the fact that Illinois health data shows that the number of new daily COVID cases has doubled in the last two weeks alone.

In the United States, the average number of new daily cases is up 66% from just a week ago, and up 145% from two weeks ago, according to Johns Hopkins University. Hospitalizations, traditionally a lagging indicator of new COVID outbreaks, are already up 26%, and that number is also expected to climb.

Is It More Dangerous Than Previous Strains?

While the delta variant is known to be more contagious than previous strains, conclusive evidence is not yet available on whether the variant is more dangerous, or more likely to land patients in hospitals.

According to Yale Medicine, one study in Scotland did show that delta was twice as likely to cause hospitalization as the alpha variant, but other studies have shown little to no difference between the two in that regard.

It is also unclear on whether delta will cause more breakthrough cases in those patients who are already fully vaccinated against COVID-19, according to a research article.

Chicago Mayor Lori Lightfoot said she was “sounding the alarm” Tuesday due to a recent uptick in coronavirus cases across the city. NBC 5’s Natalie Martinez has the story.

Will it Become the Dominant Strain in Illinois?

Judging by how quickly the virus has become the dominant strain of the disease in the US, making up an astonishing 83% of sequenced cases in the United States according to new data from the Centers for Disease Control and Prevention, it’s likely only a matter of time until it is the dominant strain in Illinois as well.

According to Chicago Department of Public Health Commissioner Dr. Allison Arwady, city and state health officials expect the delta variant to become the dominant strain of the disease within the next month.

As a result, COVID cases and hospitalizations are on the rise in virtually every state, including in Illinois. Some parts of the state are seeing positivity rates approaching the 8% mark, including in Region 4 in southwestern Illinois, and others are already seeing increases  because of the disease.  

Dr. Allison Arwady, commissioner of the Chicago Department of Public Health, delivers a COVID-19 update on Tuesday, July 20, 2021.

Are Current COVID Vaccines Effective Against the Variant?

Despite the rapid increase in COVID cases, researchers and public health officials are still urging residents to get vaccinated against the virus, saying that all three treatments that have emergency use authorization from the FDA offer protection against the delta variant.

According to researchers, the Pfizer/BioNTech vaccine is 84% effective against the variant after two doses, and is even more effective at preventing hospitalizations, doing so in at least 96% of cases, according to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

The Moderna vaccine is still undergoing testing, but company officials say that the vaccine has produced “promising protection in a lab setting” against the variant, along with several others that are currently spreading in the US.

The Johnson & Johnson vaccine shows “strong, persistent” protection against the variant, according to a statement by the company, with former FDA commissioner Dr. Scott Gottlieb estimating that the one-shot vaccine is approximately 60% effective against the variant.

Researchers at all three companies are working on potential booster shots to help counteract the effects of the delta variant, with Pfizer announcing that it will soon begin clinical trials on a booster, pending approvals from federal health officials.

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