Nearly one in five American adults who have had COVID-19 still have long COVID, the Centers for Disease Control and Prevention reported this week.

According to the Household Pulse Survey, more than 40 percent of adults in the United States have had a bout with COVID-19 and 19 percent of them are still having symptoms three or more months after infection.

And with high virus transmission in Yolo County — and the BA.5 variant evading immune protection from prior infection or vaccination — that’s another reason to wear masks in indoor public spaces, Health Officer Dr. Aimee Sisson said Tuesday.

“We’re still learning about long COVID, which is symptoms that last longer than several weeks after the original infection,” Sisson said.

Those longterm symptoms may include tiredness or fatigue, difficulty thinking or concentrating, forgetfulness, memory problems (sometimes called “brain fog”), difficulty breathing or shortness of breath, joint or muscle pain, fast-beating or pounding heart (heart palpitations), chest pain, dizziness on standing, menstrual changes, changes to taste/smell or inability to exercise.

The risk for long covid seems to be higher in those who have more severe symptoms with their infection, Sisson said, but there are plenty of people with mild or nearly asymptomatic infections who have a long duration of symptoms that qualifies as long covid.

“Being vaccinated does protect against long COVID, but it’s not a hundred-percent guarantee that you won’t get long COVID,” Sisson said. “And having had COVID before is not a guarantee that you won’t end up with prolonged symptoms.

“So that’s all the more reason to mask up indoors even if you’re fully vaccinated, boosted and/or have had COVID before.”

According to the CDC, one in 13 American adults has long COVID, defined as symptoms lasting three or more months after first contracting the virus.

Older adults are less likely to have long COVID than younger adults, with nearly three times as many adults ages 50 to 59 having long COVID compared to those 80 and older. Women are more likely than men to have long COVID, the CDC reported.

Long COVID is most prevalent among Hispanics, with nearly 9 percent of Hispanic adults currently having long COVID, compared to 7.5 percent of non-Hispanic white adults; 6.8 percent of Black adults; and 3.7 percent of Asian adults, according to the CDC.

The latest data on long COVID comes as many are experiencing a different sort of COVID fatigue — a desire to return to a pre-pandemic normal.

Running up against that desire is the strong recommendation from Sisson and other health officers to continue wearing face masks even though high virus transmission is not leading to a comparable rise in hospitalizations and deaths. It can lead to long COVID, they note.

Not to mention, “every infection is an opportunity for the virus to mutate and evolve,” said Sisson.

“And the widespread levels of infection that we’re experiencing not just in California but around the U.S. and around the world, is why it feels like this pandemic is never going to end, because the more infections there are, the more mutations there are. We get variants that evade immunity and are highly infectious and we keep going through this vicious cycle.

“So certainly if we’re able to reduce the number of cases through vaccination, through indoor masking, then we get one step closer to endemic,” Sisson said.

— Reach Anne Ternus-Bellamy at aternus@davisenterprise.net. Follow her on Twitter at @ATernusBellamy.