Summary Background Following the start of COVID-19 vaccination in New...Leer más
A US Food and Drug Administration (FDA) advisory committee on Friday voted 19-0 to authorize second doses of the Johnson & Johnson COVID-19 vaccine in an effort to boost immunity. It was the second vote in as many days to back a change to a COVID vaccine timeline.
In its vote, the committee said that boosters could be offered to people as young as age 18. However, it is not clear that everyone who got a Johnson & Johnson vaccine needs to get a second dose. The same panel voted Thursday to recommend booster shots for the Moderna vaccine, but for a narrower group of people.
It will be up to a Centers for Disease Control and Prevention (CDC) panel next week to make more specific recommendations for who might need another shot. The CDC’s Advisory Committee on Immunization Practices is scheduled to meet next Thursday to discuss issues related to COVID-19 vaccines.
Studies of the effectiveness of the Johnson & Johnson vaccine in the real world show that its protection — while good — has not been as strong as that of the mRNA vaccines made by Pfizer and Moderna, which are given as part of a two-dose series.
In the end, the members of the FDA’s Vaccines and Related Biological Products Advisory Committee said they felt that the company hadn’t made a case for calling their second shot a booster, but had shown enough data to suggest that everyone over the age of 18 should consider getting two shots of the Johnson & Johnson vaccine as a matter of course.
This is an especially important issue for adults over the age of 50. A recent study in The New England Journal of Medicine found that older adults who got the Johnson & Johnson vaccine were less protected against infection and hospitalization than those who got mRNA vaccines.
The company presented data from six studies to the FDA panel in support of a second dose that were limited. The only study looking at second doses after 6 months included just 17 people.
These studies did show that a second dose substantially increased levels of neutralizing antibodies, which are the body’s first line of protection against COVID-19 infection.
But the company turned this data over to the FDA so recently that agency scientists repeatedly stressed during the meeting that they did not have ample time to follow their normal process of independently verifying the data and following up with their own analysis of the study results.
Peter Marks, MD, director of the FDA’s Center for Biologics Evaluation and Research, said it would have taken months to complete that rigorous level of review.
Instead, in the interest of urgency, the FDA said it had tried to bring some clarity to the tangle of study results presented that included three dosing schedules and different measures of effectiveness.
“Here’s how this strikes me,” said committee member Paul Offit, MD, a professor of pediatrics and infectious disease at Children’s Hospital of Philadelphia in Pennsylvania. “I think this vaccine was always a two-dose vaccine. I think it’s better as a two-dose vaccine. I think it would be hard to recommend this as a single-dose vaccine at this point.”
“As far as I’m concerned, it was always going to be necessary for J&J recipients to get a second shot.” said James Hildreth, MD, PhD, president and CEO of Meharry Medical College in Nashville, Tennessee.
Archana Chatterjee, MD, PhD, dean of the Chicago Medical School at Rosalind Franklin University of Medicine and Science in Illinois, said she had changed her vote during the course of the meeting.
She said that, based on the very limited safety and effectiveness data presented to the committee, she was prepared to vote against the idea of offering second doses of Johnson & Johnson shots.
But after considering the 15 million people who have been vaccinated with a single dose and studies that have suggested that close to 5 million older adults may still be at risk for hospitalization because they’ve just had one shot, “This is still a public health imperative,” she said.
“I’m in agreement with most of my colleagues that this second dose, booster, whatever you want to call it, is necessary in these individuals to boost up their immunity back into the 90-plus percentile range,” Chatterjee said.
Who Needs a Second Dose?
On Thursday, the committee heard an update on data from Israel, which saw a wave of severe breakthrough infections during the Delta wave.
COVID-19 cases are falling rapidly there after the country widely deployed booster doses of the Pfizer vaccine.
The FDA’s Marks said today that the agency was leaning toward creating greater flexibility in the emergency use authorizations (EUAs) for the Johnson & Johnson and Moderna vaccines so that boosters could be more widely deployed in the United States too.
The FDA panel on Thursday voted to authorize a 50-milligram dose of Moderna’s vaccine — half the dose used in the primary series of shots — to boost immunity at least 6 months after the second dose.
Those who might need a Moderna booster are the same groups who’ve gotten a green light for third Pfizer doses, including people over 65, adults at higher risk for severe COVID-19, and those who are at higher risk because of where they live or work.
The FDA asked the committee on Friday to discuss whether boosters should be offered to younger adults, even those without underlying health conditions.
“We’re concerned that what was seen in Israel could be seen here,” Marks said. “We don’t want to have a wave of severe COVID-19 before we deploy boosters.”
Trying to Avoid Confusion
Some members of the committee cautioned Marks to be careful when expanding the EUAs, because it could confuse people.
“When we say immunity is waning, what are the implications of that?” said Michael Kurilla, MD, PhD, director of the Division of Clinical Innovation at the National Institutes of Health.
Overall, data show that all the vaccines currently being used in the United States — including Johnson & Johnson — remain highly effective for preventing severe outcomes from COVID-19, like hospitalization and death.
Booster doses could prevent more people from even getting mild or moderate symptoms from “breakthrough” COVID-19 cases, which began to rise during the recent Delta surge. The additional doses are also expected to prevent severe outcomes like hospitalization in older adults and those with underlying health conditions.
“I think we need to be clear when we say waning immunity and we need to do something about that, I think we need to be clear what we’re really targeting [with boosters] in terms of clinical impact we expect to have,” Kurilla said.
Others pointed out that preventing even mild-to-moderate infections was a worthy goal, especially considering the implications of long-haul COVID-19.
“COVID does have tremendous downstream effects, even in those who are not hospitalized. Whenever we can prevent significant morbidity in a population, there are advantages to that,” said Steven Pergam, MD, MPH, medical director of infection prevention at the Seattle Cancer Care Alliance in Washington.
“I’d really be in the camp that would be moving towards a younger age range for allowing boosters,” he said.
Créditos: Comité científico Covid