■ COVID’S lingering effects can put the brakes on elective surgeries.

The week before Brian Colvin was scheduled for shoulder surgery in November, he tested positive for COVID-19. What he thought at first was a head cold had morphed into shortness of breath and chest congestion coupled with profound fatigue and loss of balance.

Now, seven months have passed and Colvin, 44, is still waiting to feel well enough for surgery. His surgeon is concerned about risking anesthesia with his ongoing respiratory problems, while Colvin worries he’ll lose his balance and fall on his shoulder before it heals.

“When I last spoke with the surgeon, he said to let him know when I’m ready,” Colvin said. “But with all the symptoms, I’ve never felt ready for surgery.”

As the number of people who have had COVID grows, medical experts are trying to determine when it’s safe for them to have elective surgery. In addition to concerns about respiratory complications from anesthesia, COVID may affect multiple organs and systems, and clinicians are still learning the implications for surgery. A recent study compared the mortality rate in the 30 days following surgery in patients who had a COVID infection and in those who did not. It found that waiting to undergo surgery for at least seven weeks after a COVID infection reduced the risk of death to that of people who hadn’t been infected in the first place. Patients with lingering COVID symptoms should wait even longer, the study suggested.

But, as Colvin’s experience illustrates, such guideposts

may be of limited use with a virus whose effect on individual patients is so unpredictable.

“We know that COVID has lingering effects even in people who had relatively mild disease,” said Dr. Don Goldmann, a professor at Harvard Medical School who is a senior fellow and chief scientific officer emeritus at the Institute for Healthcare Improvement. “We don’t know why that is. But it’s reasonable to assume, when we decide how long we should wait before performing elective surgery, that someone’s respiratory or other systems may still be affected.”

The study, published in the journal Anaesthesia in March, examined the 30-day postoperative mortality rate of more than 140,000 patients in 116 countries who had elective or emergency surgery in October. Researchers found that patients who had surgery within two weeks of their COVID diagnosis had a 4.1 percent adjusted mortality rate at 30 days; the rate decreased to 3.9 percent in those diagnosed three to four weeks before surgery, and dropped again, to 3.6 percent, in those who had surgery five to six weeks after their diagnosis. Patients whose surgery occurred at least seven weeks after their COVID diagnosis had a mortality rate of 1.5 percent 30 days after surgery, the same as for patients who were never diagnosed with the virus.

Even after seven weeks, however, patients who still had COVID symptoms were more than twice as likely to die after surgery than people whose symptoms had resolved or who never had symptoms.

Some experts said seven weeks is too arbitrary a threshold for scheduling surgery for patients who have had COVID. In addition to patients’ recovery status from the virus, the calculus will be different for an older patient with chronic conditions who needs major heart surgery, for example, than for a generally healthy person in their 20s who needs a straightforward hernia repair.

“Long COVID” patients like Colvin who continue to have debilitating symptoms months after 12 weeks have passed require a more thorough evaluation before surgery, said Dr. Beverly Philip, president of the American Society of Anesthesiologists.

For Colvin, whose right rotator cuff is torn, delaying surgery is painful and may worsen the tear. But the rest of his life is on hold, too. A sales representative for an auto parts company, he hasn’t been able to work since he got sick. His balance problems make him reluctant to stray far from his home in Crest Hill, Illinois.

Some days he has more energy and isn’t as short of breath. Colvin hopes it’s a sign he’s slowly improving. But it’s hard to be optimistic about the virus.

“It’s always something,” he said.