Should I be worried about the Delta variant?

June 29, 2021

As a new coronavirus strain known as the Delta variant has emerged, public health experts are warning that it may lead to new outbreaks in the U.S., with unvaccinated individuals being most at risk. First identified in India, this variant, also known as B.1.617.2, is showing to be the most contagious form of SARS-CoV-2 yet observed and could cause outbreaks in areas of the country where there are large clusters of unvaccinated people. Researchers at Penn State help explain why this is the case and what we all can do to help prevent a new epidemic heading into the fall.

I’m unvaccinated. How might the Delta variant affect me?

Because the Delta variant has been shown to be more contagious, people who are unvaccinated are not only putting their own health at risk but are also jeopardizing the safety of other unvaccinated people, including children. In addition to the health impacts, new outbreaks in communities with low vaccination coverage may further delay the relaxation of restrictions or trigger the return to restrictions, thus hampering our ability to resume our normal activities, including traveling and attending concerts and sporting events. Vaccination will slow the spread of all the variants, thus reducing the chance that new and potentially more dangerous variants may emerge and helping to put an end to the pandemic more quickly. 

What is the expected impact of the Delta variant?

Already responsible for 1 in 5 infections in the U.S., the Delta variant is expected to dominate infections across the country in the coming weeks. Given the increased contagiousness of Delta, models predict that COVID-19 could increase from 1,000 deaths per week this summer to more than 3,000 deaths per week this fall and winter. But the models also suggest that 10,000 cumulative deaths could be avoided by late November if 86% of Americans are vaccinated. At the current vaccination pace, the U.S. is expected to hit 75% by September and 86% by November. However, the Delta variant could trigger surges of infections in parts of the country where there are larger pockets of unvaccinated people, thus delaying our ability to resume normal activities.

Do the vaccines work against the Delta variant?

Yes. All the vaccines appear to provide excellent protection against all the variants, including Delta. In fact, research shows that two doses of the Pfizer vaccine are 88% effective at reducing a person’s risk of developing COVID-19 symptoms for the Delta variant. By contrast, research shows that a single dose of the Pfizer-BioNtech vaccine only reduces risk by 33%; therefore, it is critically important to follow through with your scheduled second dose of the Pfizer-BioNtech or Moderna vaccine.

So, if individuals are fully vaccinated there is a small, but unlikely, chance of getting the Delta variant. And if you do, it is more likely you will be asymptomatic or have only a mild case of COVID-19, and the viral load will likely not be high enough to transmit. This new variant is yet another reason to get vaccinated.

Are the vaccines safe?

All three vaccines — Pfizer-BioNTech, Moderna and Johnson & Johnson — have been thoroughly tested and found to be safe and effective. In addition to their demonstrated safety in clinical trials, the vaccines have been safely administered to millions of people in the U.S. The FDA and CDC continue to carefully monitor the vaccines for any adverse reactions. By contrast, getting COVID-19 can be dangerous, and some patients may develop long-haul symptoms lasting for months.

What about immunity from previous infection? Will that prevent infection from the Delta variant?

No, not necessarily. Research suggests that getting vaccinated after recovering from COVID-19 provides stronger and longer-lasting combined protection against future infections than from naturally occurring antibodies alone. So far, full vaccination (with any of the vaccines) has shown strong protection against all common variants. Therefore, people are strongly encouraged to get fully vaccinated even if they’ve already had COVID-19.

Is the Delta variant as transmissible as the coronavirus can get?

We don’t yet know if the Delta variant is as transmissible as SARS-CoV-2 can get. We do know that in areas where vaccination rates are low, variants can more easily emerge and spread. These variants have the potential to be more transmissible, as we are seeing with the Delta variant. The more opportunities that SARS-CoV-2 has to circulate in an unvaccinated population, the stronger it may become, which again reinforces how important it is to get vaccinated.

Is there anything we can do to prevent missing out on activities?

Get vaccinated. It is the most important thing you can do to help us all get back to the activities we enjoy. The vaccines are proving to be effective at preventing serious illness and transmission, which protects both the individual and people with whom they are in contact. Hang in there until vaccines are available for kids, but if you’re in a household with a child or someone unvaccinated, we recommend that you exercise caution and avoid situations where there are higher chances to get infected.

You can help by getting the vaccine and encouraging everyone ages 12+ to do so, as well. Unvaccinated people need to continue to be diligent about mask-wearing, physical distancing and other precautions.

Penn State students, faculty and staff are strongly encouraged to get the COVID-19 vaccine and should upload their vaccination records as soon as possible. With this information, University officials will be able to better assess vaccination rates across Penn State and plan for the fall activities that we all love. The latest vaccination information is available on Penn State’s virus information website.

Last Updated August 11, 2021