SAN DIEGO, Calif. — Amid the shortage of COVID-19 vaccines, some new research offers a potential way to free up supply: give people who have recovered from the virus just one dose instead of two.
Two studies released this month show people who were previously infected with the virus produced a robust antibody response after their first vaccination. Neither study has been peer-reviewed.
Researchers from the Icahn School of Medicine at Mount Sinai also found that COVID survivors tended to experience more severe short-term side effects from the vaccine. “This begs the question if individuals with pre-existing immunity should even receive a second dose of vaccine,” the authors wrote.
That study out of New York analyzed antibody levels in 109 people. It found the level of antibodies produced in COVID survivors after just one mRNA vaccine dose is “equal to or even exceeds” the levels found in unexposed people who get two doses. COVID survivors had 10 times more antibodies after the first shot.
“Now, there's no change in policy yet,” cautioned Dr. Christian Ramers of Family Health Centers of San Diego, who was not involved in the study. “Part of that is because we don't really know exactly what level of antibodies you need to be fully protected.”
Currently, the Centers for Disease Control and Prevention recommends eligible adults get two doses of the mRNA vaccines, including COVID survivors. Those who have recovered from the virus should wait 90 days or more before seeking a vaccine because they have a minimal risk of reinfection during that time.
Experts say it’s not surprising that COVID survivors would produce more antibodies on first contact with the vaccine. Their immune systems are already on high alert to identify the spike protein found on the surface of the coronavirus. mRNA vaccines spur the body’s cells to manufacture a dummy version of the spike protein.
In a related finding, the New York study showed COVID survivors tended to have more severe side effects to the first shot than patients who did not have pre-existing antibodies. About 50 percent of the COVID survivors experienced fatigue after the first shot, compared to about 25 percent of the unexposed patients.
The COVID survivors also experienced significantly higher rates of headache, chills and fever.
Dr. Mark Sawyer of Rady Children’s Hospital said the findings make sense because those side effects are a sign your body’s immune system is jumping into action.
“So we know that second doses of the vaccine have more side effects. This is essentially the same as that: vaccination after infection is just like having a second dose of vaccine,” he said.
Dr. Peter Chin-Hong, an infectious disease expert at UC San Francisco, said the findings were in line with his own anecdotal experience in the clinic.
"Just the other day I was in the hospital and I talked to one of my colleagues who unfortunately had COVID a few months ago. He got the shot and he said wow, it really knocked him out," Chin-Hong said.
The study authors urged the CDC to reconsider the advice that COVID-19 survivors receive two doses.
“Changing the policy to give these individuals only one dose of vaccine would not negatively impact on their antibody titers, spare them from unnecessary pain and free up many urgently needed vaccine doses,” the authors wrote.
However, other experts say implementing the one-dose policy could be tricky. People’s past infection status would have to be confirmed.
Dr. Sawyer, who sits on the FDA’s vaccine advisory committee, noted the data is thin.
“I don't think we have enough data on the single dose following infection to know whether that is going to be good enough,” he said, “so I don't think we're ready to make that recommendation.”
This story was first published by Derek Staahl at KGTV in San Diego, California.