The Delta variant (since October 5th 2020), aka B.1.617.2, is the most contagious strain of covid-19 to date. It began in India in October, likely killing millions by April and May (probably the case, but not yet proved). By July 20th in the US it accounted for 83% of all new cases, which are now on the rise once again:
The UK saw a similar rise in June. Because of the Delta variant, most spectators will be barred from the Tokyo Olympics that start tomorrow (July 23rd).
The Delta variant is about three times more contagious than the original coronavirus, putting it on track to become the main variant worldwide, as it already is in the US and UK. It is unclear whether it is deadlier. Early studies show that people become infectious sooner (in four days instead of six) but are not any more likely to be hospitalized.
Symptoms: as with other variants, a persistent cough, headache, fever, and sore throat. One study showed that cough and loss of smell are less common, but headache, sore throat, runny nose, and fever are more common.
If you have been vaccinated you do not have much to worry about: there is a 93% chance the vaccine will prevent the Delta variant from hospitalizing you. Pfizer wants to make a booster shot. The CDC says there is no need yet for a booster shot so long as you are fully vaccinated.
If you are not vaccinated, then your chances of getting covid have just gone up. As Dr. Ashish Jha, dean of the Brown School of Public Health, puts it:
“This is a very, very dangerous moment to be unvaccinated with this variant circulating.”
Based on vaccination rates in the US, the Delta variant will hit red states, Blacks and Hispanics the hardest. In June, over 99% of those who died of covid were unvaccinated.
Herd immunity: Because the Delta variant is more contagious, that means higher rates of vaccination will be required before covid-19 becomes a thing of the past, probably more than 70%. So this whole thing is going to drag on longer than expected. Worldwide only 10% are vaccinated. In the US, 67% of adults are at least partly vaccinated.
Variants of covid-19 so far:
- Alpha (aka B1.1.7): began in September 2020 in the UK.
- Beta (aka B.1.351): began in May 2020 in South Africa.
- Gamma: (aka P.1): began in November 2020 in Brazil.
- Delta (aka B.1.617.2): began in October 2020 in India.
“Delta” is the name the World Health Organization (WHO) gave it. “B.1.617.2” is what scientists call it based on its genetic lineage.
No doubt Epsilon and other variants are yet to come.
The Delta variant has a new and improved spike. Those red spikes you see in pictures is how the coranavirus sticks to your lung cells so that it can infect them. (The spikes, by the way, are not red. That is an artistic convention. Viruses are too small to have colours.)
– Abagond, 2021.
Sources: mainly PBS, NPR, WebMD, BBC, BNC News.
See also:
- germs, the last 13,000 years
- pandemic
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