The Medical Minute: What to know about the delta variant

July 14, 2021

Right in the middle of a summer that is looking and feeling much more like normal, news of a rapidly spreading delta variant of SARS-CoV-2―the virus that causes COVID-19―is unsettling and causing lots of questions.

According to data released by the Centers for Disease Control and Prevention (CDC), the SARS-CoV-2 delta variant has increased from about a third of cases in the U.S. in early June to more than half of new cases in early July.

It is much more easily transmitted from person to person, and some reports suggest it causes more severe disease ― although more information is needed to say for sure.

What’s my best protection?

Get vaccinated.

“This variant will have the greatest impact on the unvaccinated,” said Dr. Catharine Paules, an infectious diseases physician at Penn State Health Milton S. Hershey Medical Center. “The vaccines may be a little less effective at preventing delta-related illness, but remain over 90% effective at preventing hospitalizations and death.”

“People who are vaccinated and develop a breakthrough infection are not thought to have very high levels of the virus in their respiratory tracts, so they are thought to be less likely to transmit infection to others, although less is known about the risk of vaccinated people spreading the delta variant,” said Dr. Leslie Parent, an infectious diseases physician at the Milton S. Hershey Medical Center and vice dean for research and graduate studies at Penn State College of Medicine.

“Vaccination also lessens the chance that new variants will emerge that could spread more easily, cause more severe disease or become more resistant to vaccines, antibody treatments and antiviral drugs,” she said.

Do we have a lot of the delta variant in Pennsylvania?

Fortunately, a relatively high percentage of Pennsylvania’s adult population has been vaccinated, according to the CDC COVID data tracker. More than 60% of people older than 18 have been fully vaccinated, and 75% have received a first dose. At this time, a small proportion of the COVID-19 cases in Pennsylvania are caused by the delta variant. This is in contrast to places with lower vaccination rates. In Missouri, for example, where just 39.7% of the population is fully vaccinated, the delta variant accounts for 73% of new COVID-19 cases.

“At Hershey Medical Center, we have detected about one delta variant a week; however, the U.K. variant remains the most common, and hopefully it stays this way,” said Wallace Greene, director of the Diagnostic Virology Laboratory at the Medical Center, noting that COVID-19 testing and positive samples continue to decrease.

In that case, should I even be concerned?

As people travel on summer vacations to places where vaccination rates are lower and gather again in larger groups that undoubtedly include some unvaccinated adults and children, now is not the time to let your guard down.

States with lower vaccination rates have seen an uptick in cases, and “we certainly don’t want to bring any of that here,” Greene said.

People who are not vaccinated are more susceptible to becoming infected and can transmit the virus more readily to others, even if they themselves have no or few symptoms, Parent said. “Those transmitted infections may cause severe disease in some people and overwhelm the health care system in the area,” she said.

Are the symptoms of the delta variant different or more dangerous?

“The symptoms appear to be similar, although we will learn more as new studies are published,” Parent said. “Information from Scotland published in the Lancet (medical journal) suggests that people in younger age groups are being infected with the delta variant and infection with delta is associated with a two-fold increased risk of hospitalization compared to the alpha variant.”

Should I think about masking or social distancing again?

While guidelines on wearing masks and social distancing have loosened, people should take into account their surroundings, their own health considerations and what they know about the region of the country where they are, doctors said.

“I work with stem cell transplant patients, so I continue to wear a mask and social distance even though I am vaccinated, because I don’t want to risk bringing anything to them,” Paules said. 

“It is important to consider both your own risk and the risk to your loved ones, particularly children who cannot yet be vaccinated and immunocompromised individuals who may respond less well to the vaccine,” Paules added. “This is especially true in regions of the country with high rates of delta transmission.”

Should immunocompromised people who are vaccinated take special precautions?

“Because we can’t assess at an individual level how well an immunocompromised person will be protected after vaccination or previous infection, it would be safest for those with risk factors for serious complications and anyone who is immunocompromised to continue to wear masks, avoid large gatherings and maintain social distancing, even if they have been vaccinated,” Parent said.

What’s the latest on booster shots for the COVID-19 vaccine?

“We just don’t know yet. If we see vaccine breakthrough infections in larger amounts, that may be a clue that a booster is needed,” Paules said. “There may ultimately be different recommendations for someone who is 80 years old versus someone in their 20s or immunocompromised patients.”

Right, now, she said, the most important step is get vaccinated. “Do it for yourself, for your loved ones and for your community. That’s how we’ll get out of this,” she said.

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The Medical Minute is a weekly health news feature produced by Penn State Health. Articles feature the expertise of faculty, physicians and staff, and are designed to offer timely, relevant health information of interest to a broad audience.

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Last Updated August 12, 2021