All You Need to Know About the Delta Variant

Q: Can you explain what variants are, particularly the Delta variant?

The coronavirus tends to have a high mutation rate and that is why we keep seeing a changing genomic signal of the virus in the population. The genomic signal is what the CDC monitors and these tests are done throughout the country to monitor the variant that is most prevalent.

The CDC tracks multiple variants circulating in the United States and provides an estimate of how common they are at the national and regional levels. This data can change over time as more information becomes available.

There are hundreds of mutations if not more. The variants of interest or concern per the CDC were named, originally by their site where first identified such as the U.K. variant, the Brazil variant and so on. Now names are given in order of discovery using the Greek alphabet so alpha, then beta and so on. There is also a coding system used to identify each variant—B.1.1.7 is known as the Alpha variant.

The Delta variant is currently of most concern. However, the latest variant to be highlighted by the World Health Organization is called Lambda, and now been found in at least 27 different countries. It is not yet listed as a ‘variant of concern’, rather a ‘variant of interest’ by the WHO, meaning it has been identified as causing transmission or detected in multiple countries.

Q: Where did the Delta variant come from and how far has it spread?

Delta, also known as B.1.617.2, was first identified in India during a ferocious wave of infections there in April and May. Delta is currently on the rise in the United States, particularly in the Midwest and Southeast. The CDC declared it a variant of concern on June 15, 2021.

Delta is spreading fast. Using a rapid genotyping test, companies have found that the proportion of cases caused by Alpha fell from more than 70% in late April to around 42% as of mid-June, with the rise of Delta driving much of that shift. Delta seems to be around 60% more transmissible than the already highly infectious Alpha variant identified in the United Kingdom in late 2020.

Q: How can you tell if you have the Delta variant? Are there additional symptoms?

Some reports suggest that the Delta strain could cause different symptoms than other variants. A U.K. study, for example, reported a change in the top-ranked symptoms since Delta starting dominating. Cold-like symptoms, including headache, runny nose and a sore throat, now top the list in that study, while more traditional COVID-19 symptoms — loss of smell, shortness of breath, fever and persistent cough — have since moved down. Doctors in the U.S. are noting a similar trend, especially in areas that have some of the highest rates of Delta cases.

Regular COVID-19 tests do not detect which variant is involved in a patient’s case—that information does not change the approach to care or therapy. The variant identification requires genomic sequencing, a process separate from regular virus tests and one that not all labs are able to do or do not do on a routine basis for patient care but are done more for public health monitoring.

Q: Is the Delta variant more deadly?

While an increase in infections alone is troubling and can lead to more deaths—both through the increase in cases and by overwhelming the health system—early research suggests Delta is possibly more dangerous than the Alpha variant and twice as likely to lead to hospitalization.

Q: Is the vaccine effective against the Delta variant?

Yes. All of the vaccines available in this country have been shown to be highly effective against all current variants meaning that the vaccine reduces the chances of getting a severe illness, being hospitalized or dying from COVID-19. However, Delta is moderately resistant to vaccines in people who have received just a single dose of the Pfizer or the Moderna vaccine. So, the message is that the vaccines, in individuals who are fully vaccinated, are effective against the Delta variant.

Q: Do masks protect against the Delta variant? What other things can be done to protect against it?

Because of what we know about the way coronavirus spreads, masks help protect against infection by decreasing the ability to inhale the droplets. So yes, mask do protect against the Delta variant. All other measures that we have used to date to mitigate spread of the virus which includes the hand washing and social distancing, and most importantly getting vaccinated, are the best ways to protect against getting COVID-19 whether it is from the Delta variant or any other variant.

For this reason, a decision about mask wearing should take into account some additional factors. The CDC says that vaccinated people do not need to wear masks when in public and can resume pre-pandemic activities unless other local regulations or restrictions are in place. But, depending on your comfort level and your underlying health status, you may still consider wearing a mask if you are potentially around a lot of people who may be unvaccinated, especially in a crowded space, to decrease that risk of low-grade infection. You should also consider wearing a mask if you are in an area of the country where surges, possibly due to the Delta variant are occurring.

Q: Is there anything else you think the public needs to know?

The dominance of this variant in the U.S. now coupled with the loosening of social distancing restrictions means we are seeing surges of COVID-19 cases, hospitalizations and deaths in areas of the country where vaccination rates are low. The best way to protect yourself is to get vaccinated. Recent data suggests that 99% of the current deaths in this country caused by COVID-19 are among unvaccinated individuals. Get vaccinated!