Delta Variant and Long COVID Are the Biggest Pandemic Issues, Experts Say

Last week, infectious diseases experts from the Johns Hopkins Bloomberg School of Public Health met to discuss two major public issues of the pandemic: the Delta variant and long-COVID. The July 14 media briefing came on the heels of Delta becoming the dominant COVID-19 strain in the United States.

Immunity and the Delta Variant

COVID-19 infection rates were lower in May and June than at any time since the start of the pandemic, said David Dowdy, MD, an associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

“This is largely attributable to vaccination, with nearly 60% of adults in the U.S. being fully vaccinated," Dowdy said at the briefing. "Of those who have not been [vaccinated], probably over a third have been infected and are also likely immune.”

This means the majority of the population has a significant level of immunity against COVID-19, he added.

But Dowdy said the number of reported cases has doubled in the last couple of weeks. Many of these cases are due to the Delta variant, which appears to be more easily transmitted than other strains and which has now become the dominant strain of virus in the United States.

“It's hard to know how much of the current increasing cases is due to the variant versus changes in behavior as our society has opened up,” he said. “It doesn’t mean a major wave is inevitable.”

What is clear, however, is that younger people—many of whom are unvaccinated—are at a higher risk for Delta.

“The people who are getting infected now are not the same as people who were getting infected the beginning of the pandemic," Dowdy said. "They are younger and may have different contact networks."

Although new variants may be more easily spread from person to person, they are not more likely to cause severe disease or death, Dowdy said. And for those who are able to get vaccinated, vaccines are still the best weapon against the variant.

“It's important to note that there's no evidence that the current vaccines are any less effective against the Delta variant,” he said. “Vaccines still work and work very well.”

The Prevalence of Long COVID

Eighteen months ago, at the start of the pandemic, focus was on the mortality of COVID-19. Hospitals were overrun and large number of people were dying. Now that death rates are down, researchers can focus on morbidity—the experience of someone who is unwell because of COVID-19.

“We now have what we call the chronic state of infection, and that's what we're starting to see emerge in very large numbers for COVID," Priya Duggal, PhD, professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, said at the media briefing, referring to long COVID. She says 30% of people with COVID-19 report symptoms that last more than 30 days and even up to a year after infection.

According to Duggal, long COVID symptoms are varied and include prolonged loss of taste or smell, brain fog, anxiety, depression, heart problems, kidney conditions, excessive fatigue, and difficulty breathing. It's systemic, meaning many different organ systems can be affected.

“These are all real symptoms that we're starting to see across the age spectrum of individuals who are infected with COVID-19,” Duggal said. “What’s really interesting, and what is perhaps more devastating, is that we're also seeing it among those individuals who were mildly or moderately affected, and in some cases, those who were previously asymptomatic."

About 5% of people say they have symptoms that are debilitating enough to interfere with their function in their daily life, she noted.

While Johns Hopkins is collecting information for a study of long COVID, Duggal said "we don't know what the numbers are supposed to tell us."

Information collected so far shows that long COVID tends to affect younger people: those in their 30s, 40s, and 50s. Younger women are more likely to report lasting symptoms than younger men, but it is not known if there are any differences due to race, socioeconomic class, or to other diseases a person might have.

“Until we get a handle on what the symptoms are and the spectrum of symptoms for long COVID, it's going to be difficult for healthcare workers to address,” Duggal said.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.