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Doctor who volunteered for Moderna study felt ‘lousy’ after second shot, but touts vaccine

Dr. Jorge Arroyo was among those who volunteered for the test of Moderna's vaccine at Brigham and Women's Hospital.Jessica Rinaldi/Globe Staff

Jorge Arroyo isn’t certain whether he was injected with Moderna’s coronavirus vaccine or a placebo when he volunteered to receive two shots four weeks apart during the summer. Participants and researchers in the study at Brigham and Women’s Hospital were kept in the dark to eliminate the power of suggestion.

But to Arroyo, it sure felt like he got the real thing.

The Harvard-affiliated ophthalmologist ― one of about 30,000 participants in the Cambridge biotech’s nationwide trial ― says he began feeling ill about 10 hours following the second shot. The symptoms included body aches, slight nausea, and chills. What’s more, his husband, who also participated in the trial, had a similar reaction.


Still, as plans are put into action for the expected rollout this month of Moderna and Pfizer vaccines on an emergency basis, Arroyo is urging people to get their shots “as soon as it becomes available to you.” He says the side effects, which disappeared within 24 hours, would be a small price to pay for the benefits of immunization.

“It made me feel lousy, albeit for a day,” said Arroyo, associate chief of ophthalmology at Beth Israel Deaconess Medical Center. “Had I got infected with COVID, I imagine I’d feel much worse and possibly dying.”

Indeed, the malaise he felt the morning after receiving the second shot in his left shoulder didn’t stop him from working out with a 150-pound barbell at his Brookline house, or from seeing patients afterward.

Arroyo, who gives his age as between 50 and 60, says he has described his experience to about 100 of his eye patients, as well as to relatives and friends. He is a native of Puerto Rico, and roughly half of his patients speak Spanish. Many are skeptical of getting a vaccine despite the disproportionate toll the epidemic has taken on Hispanic people.


Dr. Lindsey Baden, an infectious-diseases specialist at the Brigham who was among three investigators who led the nationwide late-stage trial of Moderna’s vaccine, said the side effects described by Arroyo were in line with those experienced by some other participants.

“Most people don’t actually have the reaction [he did], but a significant portion do, and that’s the pattern that’s been seen,” Baden said. “There are increased reactions after the second dose. It comes on pretty quickly ― 10 or 15 hours after the second vaccination ― and then it’s gone by the next day.”

Baden, who doesn’t know which participants got the vaccine and which got the placebo, likened the potential side effects to those reported by some recipients of Shingrix, a vaccine for shingles made by GlaxoSmithKline that was approved in 2017.

“By knowing about it, you can plan, so the day after the second [coronavirus] shot, you’re not surprised that you have some degree of discomfort,” Baden said.

An independent board that evaluated Moderna’s study results for the National Institutes of Health found no serious safety concerns and determined that the vaccine was more than 94 percent effective at preventing COVID-19. The two-dose vaccine developed by Pfizer and a German biotechnology partner, BioNTech, uses the same technology and generated similar results.

An advisory committee to the Food and Drug Administration plans to vote Thursday on whether the Pfizer-BioNTech vaccine should be authorized for emergency use by people at high risk for catching the coronavirus or who are likely to get severely ill because they are older or have underlying conditions. The same committee is expected to vote on Moderna’s vaccine on Dec. 17.


At least 500 volunteers received shots at Moderna’s trial site at the Brigham, Baden said. Moderna had about 100 such sites across the country.

Arroyo, who shared his story after the Globe contacted the Brigham, said he volunteered for several reasons. He firmly believes in scientific research, especially at a time when, as he put it, “we are in the middle of a major trust deficit.” As a retina surgeon, he treats many patients whose vision problems stem from diabetes, a significant risk factor for suffering severe COVID-19.

On a personal level, at least once a week he visits his 79-year-old mother, Carol Arroyo, who has early dementia. She lives at Goddard House, an assisted-living center in Brookline, and he doesn’t want to put her at risk.

Arroyo and his husband, a primary care doctor at Beth Israel, got their first shots in early August. Their only side effects were slightly sore shoulders, he said, which led them to believe they may have gotten a placebo.

But the night of their second shots in early September, they suffered the side effects. To Arroyo, it felt as if he had a migraine coming on. The couple’s temperatures were slightly elevated but within the normal range.

They were still under the weather the following morning, but went about their usual routines, and within 24 hours of getting the shot, they felt fine. They have had no problems since then. Researchers believe immunity kicks in one to two weeks after the second shot.


Both the Pfizer and Moderna vaccines rely on synthetic messenger RNA, a variation on the natural substance that directs protein production in cells throughout the body. The vaccines contain custom-made messenger molecules that instruct cells to create part of the coronavirus and then stimulate the immune system to make antibodies to fend off the disease if exposed to the actual virus. No mRNA vaccine has ever been approved.

“The messenger RNA vaccine, even though it is novel, is without a doubt in my mind the simplest and safest way to give your immune system an appetizer, a taste, of a potentially lethal pathogen that it otherwise would not be exposed to,” Arroyo said.

Although the FDA said months ago it would probably approve a vaccine that was safe and at least 50 percent effective, the mRNA vaccines performed far better than that. Arroyo said when he recently read that Moderna’s data showed its vaccine was more than 94 percent effective, “I was sort of blown away.”

Baden, the researcher, said he would gladly take the Moderna or Pfizer vaccine when one becomes available. He expects to be among the earliest recipients because he treats patients with COVID-19 and is at high risk for catching it. He expects the FDA will also soon discuss when to inform people in the Pfizer and Moderna trials whether they got a vaccine or a placebo.


Pfizer’s chief executive, Albert Bourla, has said his firm is morally obliged to offer the vaccine early to people in the placebo group because they volunteered for the study.

Arroyo said that if he finds out he got the vaccine, as he believes he did, he will still wear a mask, frequently disinfect his hands, and practice social distancing.

“If everyone did that, we would not be in the situation we’re in now,” he said.

Jonathan Saltzman can be reached at jonathan.saltzman@globe.com.