FAQ: What to know about the delta variant, its spread in Maryland and what it might mean for vaccine boosters

Cases of COVID-19 in Maryland and around the country are way down from their winter peak, as are hospitalizations and deaths. That’s all thanks to the vaccines, which have proved highly effective in preventing severe disease, public health officials say. But the pandemic isn’t over, and the level of threat depends on where you live, your vaccination status, and now, a much more transmissible version known as the delta variant.

What do we know about the delta variant?

Dr. Anthony Fauci, the nation’s top infectious disease doctor, recently called the variant “the greatest threat” to containing the coronavirus pandemic.


The variant, a cluster of mutations first reported in India, appears to be at least twice as transmissible than the original virus and maybe more.

The U.S. Centers for Disease Control and Prevention reported last week that the variant is now responsible for more than half of new cases nationwide, up from about a quarter a week ago. In some states, it’s already closer to 80%.


In Maryland, officials have been testing samples from infected people in state, private and university labs. They logged 69 cases involving the delta variant through July 7. That’s a small portion of the state’s overall cases, which are still dominated by the alpha variant first seen in the United Kingdom — but the Maryland Department of Health reports delta cases are fast increasing.

The CDC is also keeping watch for other emerging variants. That includes the delta-plus variant, with an extra mutation, and the lambda variant first seen in Peru. Both appear more transmissible than the original strain and may be better at resisting vaccines.

What is the risk specifically from the delta variant?

Delta and other variants are largely a risk to those not vaccinated, health officials say.

Maryland health officials say that during June, 93% of new cases, 95% of hospitalizations and 100% of deaths were in unvaccinated people. They can’t say how many cases were caused by the delta variant, but nonetheless, public health experts say vaccines appear to continue providing protection generally from severe COVID disease.

“I’d like to emphasize the positive, that the vaccines are working,” said Andrew Pekosz, a virus researcher and professor of microbiology and immunology in the Johns Hopkins University Bloomberg School of Public Health in Baltimore.

“When we talk about a potential surge in the fall, we’re not going back to the early months of the pandemic,” he said. “The focus will be on primarily unvaccinated people.”

Then what’s the big deal for vaccinated people from the variant?

Pekosz said that vaccinated people can become infected, though they are far more likely to have mild or no symptoms, even with the delta variant.

The long-term effects of even mild infections are unknown, however, and a certain number of people develop what’s known as long-haul syndrome with persisting and new symptoms.


And the more transmissible delta variant creates a numbers game — more infections means more cases among vaccinated as well as unvaccinated people. That puts others who can’t or won’t get vaccinated at risk.

At least one country, Israel, raised concerns about a large number of “breakthrough” cases among vaccinated people. Officials say it’s not clear, however, if vaccines are really less effective at stopping infections or if immunity is waning in people vaccinated early on.

The vaccines remain the best bet to prevent severe disease, officials say. And while Maryland has a higher rate of vaccination — about 75% of adults with at least one shot, versus the U.S. average of 67% — there are pockets of vulnerable people. That raises concerns that the delta variant will be the one to catch them.

“The appearance of contagious variants, including the delta variant, underscore the urgency for all eligible Marylanders to get a vaccine, which have shown to be effective in protecting people from variants of COVID-19,” said Charles Gischlar, a spokesman for the Maryland Department of Health.

Do rising cases here and in other countries mean we need booster shots?

Pfizer said last week that it plans to pursue authorization of a third booster shot for added protection from the delta variant, possibly next month. Though, the CDC and FDA responded that officials there don’t believe that is necessary.

Officials around the country, including at the University of Maryland in Baltimore, began studying booster shots before the delta variant began dominating. They were looking into using the same vaccine or even mixing and matching different existing vaccines.


Experts say officials may determine that boosters are appropriate for seniors or those who are immunocompromised, but not for everyone.

Pfizer officials also say they are working on an updated vaccine specifically to target the delta variant. It’s also possible that vaccine makers will produce newer versions annually to target circulating strains, as they do for influenza.

Dr. Kirsten Lyke is an infectious disease expert who is heading up the booster study at the University of Maryland School of Medicine’s Center for Vaccine Development and Global Health.

“Are we going to need a booster? The answer is no one knows,” she said. “We’re looking at it in a very methodical way.”

She said officials always assumed there would be variants to contend with, but delta has spread much faster than expected, giving her work more urgency. She expects to have some answers in coming months about who should get another shot, if swapping out vaccines is a good idea and if the delta variant or other variants mean the existing vaccines need retooling.

What is being done to get more people vaccinated now that the delta variant is surging?

Federal officials, and those in Maryland, have created task forces to address gaps in vaccinations among minority groups, the hardest hit during the pandemic and among the least vaccinated. Given the swift spread of the delta variant, Democratic President Joe Biden last week suggested more needs to be done, even going door-to-door.


Data also shows that across the country and in Maryland, the youngest people have the lowest vaccination rates. Those as young as age 12 qualify for a vaccine.

Studies are ongoing in younger children, including at the University of Maryland. Pfizer has said it would request emergency authorization for its vaccine in September for those aged 5 to 11. Lyke said it would likely take federal regulators four or five weeks to review the data and then more time to distribute guidance to providers about administering doses, which are expected to be smaller than the adult dose.

What do we do in the meantime about precautions?

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The CDC says those vaccinated can resume normal activities and stop wearing masks indoors and outdoors, except in their workplaces or at businesses that continue to require masks.

Pekosz and Lyke said the unvaccinated, including children, should continue to wear masks indoors or when they can’t stay distanced from a crowd. They also said it was a good idea for vaccinated parents or those often around unvaccinated people to wear masks indoors when they aren’t at home. Everyone traveling should consider a mask when traveling to places with lower vaccination rates to contain spread of the virus.

“Travel, that’s how the virus got here in the first place,” Lyke said.

Both said many kids would head back to school in the fall without protection, either because they aren’t yet eligible or haven’t gotten a shot yet. That could contribute to a bigger uptick in cases if precautions aren’t taken.


The CDC issued guidance late last week that called on schools reopen in person in the fall, even if they can’t keep students the recommended 3 feet apart. The schools should take protective steps, such as masking unvaccinated students and staff, adding air purifiers and encouraging vaccinations for those eligible.

Experts such as Pekosz said it would not be unreasonable to ask staff and others to wear masks around unvaccinated students to protect the students and other vulnerable people at their homes.

“Transmission is going to be less likely when a lot of people are vaccinated,” Pekosz said. “But especially if you know people in your household are highly susceptible to infection, wearing face coverings is an easy thing to do to protect them.”