November 12, 2021

Delta Plus: What We Know About the Latest COVID-19 Mutation

And you already know how to protect yourself from it

Delat Varient

Every time we turn around, there’s a new COVID-19 variant at the door. And with each one’s arrival, more panic seems to set in. While it’s natural to fear the unknown, it’s also good to know that the scientific community is monitoring all variants of COVID-19 in the United States and globally.


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Infectious disease specialist Kristin Englund, MD, shares some insights about variant AY.4.2, also known as “Delta Plus,” and reminds us why we still need to be careful as we roll into the indoor months.

Q: Should we be worried about virus mutations or are they pretty normal?

A: Mutations that occur when a virus makes copies of itself are quite common. Some mutations cannot survive, some have no effect and others can make a virus more transmittable or more severe. AY.4.2 is due to a mutation of the SARS-CoV-2 delta variant. The impact of this mutation is not quite clear yet.

Q: When was AY.4.2 discovered and has it been a variant of interest for a while?

A: AY.4.2 has been followed by the World Health Organization (WHO) since July and is present now in dozens of countries. Most of the cases have occurred in the U.K. but even there, it’s only present in about 6% of the cases. In the United States, it’s been present in less than 1% of cases.

Q: How is AY.4.2 different from the original delta variant?

A: The AY.4.2 variant has three mutations, with two of them being on the spike protein. The coronavirus uses the spike protein on its outer surface to infect cells by attaching to a protein called the ACE2 receptor that is found on the surface of the lungs and other cells.


Q: Should we be worried about vaccine resistance when it comes to mutations like delta plus?

A: Mutations can cause vaccine resistance. However, there is no evidence that the AY.4.2 variant is resistant to the vaccines that are currently available. The more people get vaccinated, the fewer mutations occur and the less likely we will see a variant that is vaccine-resistant.

Q: What can we do to protect ourselves from delta plus?

A: As long as you are practicing the precautions already in place such as hand washing, masking, physical distancing and most importantly getting vaccinated, these appear to be as effective in preventing infection with AY.4.2 as with the delta variant. ​

Q: What have we learned about the original delta variant?

A: The delta variant is transmitted much easier than the first COVID-19 virus. It has hit younger populations (people in their 30s through 60s) much harder. Children and teenagers are being infected and many of these infections are resulting in ICU admissions and even death. We just topped 5 million deaths worldwide from COVID.

Other ways that the delta variant differs from earlier versions of COVID-19:

  • The delta variant is highly contagious. It’s more than twice as contagious as previous variants.
  • It causes more severe illness in unvaccinated people as compared to other variants so far.
  • It can be spread by fully vaccinated people however, they’ll spread it for less time as compared to unvaccinated people.
  • Delta infections were detectable four days after exposure. The original strain could be detected around six days. Delta infections were also contagious for a longer period of time. The period was 18 days as compared to 13 for the original strain.

Q: Why can’t we afford to ignore COVID-19 and more possible mutations as we head into winter and the holidays?

A: COVID-19 symptoms can be difficult to differentiate from flu symptoms. That’s why we must remain vigilant about flu-like illnesses and assume that they could be COVID-19. Also, as we head indoors more, the risk for transmitting COVID-19 increases.

Q: What would you say to someone who is convinced that vaccines don’t work because of breakthrough COVID-19?

A: Ninety percent of patients who have been admitted to hospitals have been unvaccinated. Unvaccinated patients are dying every day. If vaccinated patients do get a breakthrough infection, they are much more likely to either have no symptoms at all or experience mild illness.

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