The U.S. Food and Drug Administration on Tuesday released a 53-page report summarizing data from Pfizer and BioNTech’s COVID-19 candidate vaccine trials. The data support previous findings that the vaccine is safe and prevents 95% of the population from becoming ill with COVID-19.
The companies are asking the FDA for permission to use the vaccine in people aged 16 and over. They have also started testing the vaccine at the age of 12-15, but have not yet collected enough data to request permission in that age group.
The FDA panel, which must review the vaccine before the approval meets all day Thursday, with approval expected immediately that evening. Another candidate vaccine, made by Moderna, will be reviewed next week.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University School of Medicine in Nashville, Tennessee, said he recently received a briefing on the Pfizer / BioNTech data, though he would not say who presented it or who else received it. .
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“The group I was with and who heard the data arrived interested and left the presentation enthusiastic,” Schaffner said. “The extraordinary thing is that there were no major areas of concern.”
Others also seemed impressed with the results.
“The FDA did not notice any surprising findings,” said Dr. John Grabenstein, a former Merck director and former director of the U.S. Department of Defense military immunization program. Efficiency and product quality look good, Grabenstein said in an email, and there were only a few serious cases of COVID-19 in the vaccine group.
That report provides more details about how certain groups of people coped with the vaccine, called BNT162b2, including people over the age of 65, those with pre-existing medical conditions, such as diabetes, and those who are black and / or Hispanic – all of whom appeared to be as well protected as the general population.
About one-third of participants met the definition of obesity, lower than the general population in the United States but still high. The mean age of the participants was 51. They appeared to be as well or better protected than anyone else, addressing the concern that the vaccine may not work as well in people who are elderly or have conditions that may make them more vulnerable to serious illness. . .
The report also noted that the first vaccine dose appeared to be 52% protective, although because everyone received a second dose three weeks after the first, there is no evidence that protection lasts longer than a few weeks.
With other vaccines, a second or booster shot extends the protection they provide.
“We do not just want to get you through the night,” Schaffner said, adding that he would rather be pleasantly surprised if the vaccines prove to work after just one dose than unpleasantly surprised that people get sick who stopped at their first shot.
Many subjects endured side effects for a day or two after receiving their shots, especially the other. The most commonly reported adverse reaction among vaccine recipients under the age of 55 was a sore arm, followed by fatigue (60% after the second shot); headache (52% after the second shot); other muscle pain (37%); and chills (35%). Approx. 28% took painkillers after the first shot and 45% after the second shot.
There were “no surprises” in terms of safety, Grabenstein noted. Four people in the vaccinated group developed Bell’s palsy – a temporary weakness in the muscles of the face that causes one side to sag or stiffen – but which may or may not be caused by the vaccine, and the FDA described the cases as “non-serious. “
Other “serious adverse reactions” were reported in both groups, including two deaths among those receiving the active vaccine and four among placebo recipients, but were unlikely to be related to the vaccine, the report concluded.
Overall, the FDA report concluded that the data “live up to the agency’s expectations … The incidence of non-fatal serious adverse reactions was low (less than 0.5%) with no meaningful imbalance between the study arms.”
The study also noted that Pfizer / BioNTech will offer BNT162b2 to anyone who has received a placebo if they request it, and to all placebo recipients six months after their second dose.
Pfizer / BioNTech will continue to study these trial participants and will also conduct several new studies to follow people who receive the vaccine after it has been approved, according to the report.
While the vaccine has been shown to be safe among the 22,000 people who received it, rare health complications are likely to occur as it is used in hundreds of thousands and then millions of people.
Despite the thoroughness of the report, there are still unanswered questions.
Among the big ones:
How long does the vaccine last?
The FDA will consider “approving” this vaccine, but will not issue a full approval because there is no data on how long the vaccine will be protective.
Officials decided that in the midst of a pandemic, it was good enough to ensure that the vaccine was safe and at least transiently effective, rather than detaining it for two years to await the typical long-term results required for full approval.
Vaccine companies intend to follow the trial participants for two years and submit a complete application once they have this data.
The FDA noted in the report that Pfizer / BioNTech should periodically review the safety of their vaccine, including degradation by age, special populations such as pregnant women, and serious side effects.
Does the vaccine prevent infection or just symptoms?
Right now, we only know that Pfizer / BioNTech and Moderna candidate vaccines prevent COVID-19 symptoms and serious illness. It is not clear if anyone could catch the virus that causes COVID-19 and pass it on to someone else, even without getting sick.
The studies designed to test the candidate vaccines examined only symptomatic infections, not whether vaccinated could still be contagious.
This means that people who have been vaccinated can be pretty sure that they are not developing COVID-19 themselves, but they can still pass it on to others without knowing that they are infected.
Regulatory officials believed it was more important in the midst of a deadly pandemic to prevent disease and did not want to slow down trials by adding additional requirements. Future studies will examine this.
“This is one of the reasons why you will still have to continue to wear your masks and take social distance,” said Schaffner, who was not involved in the development of any of the COVID-19 candidate vaccines. but have followed the process closely. Evidence that vaccines prevent transmission, he said, “would have taken much longer, much more money, and possibly (required a) much larger trial.”
He defended the decision to focus on preventing disease instead of worrying about transmission.
“We want to keep people out of the hospital, outside the intensive care unit and not at risk of dying,” he said. “I will take that.”
Early indications from a study published Tuesday in Lancet suggests that the candidate vaccine for AstraZeneca / Oxford University at least partially prevents a vaccinated person from transmitting the disease.
Could the vaccine aggravate subsequent infections?
There has been concern that vaccination against COVID-19 may cause a subsequent COVID-19 infection, as some dengue vaccines have been shown to do for this disease.
The FDA concluded that the use of the vaccine has not been widespread enough to know with certainty, but that “available data do not indicate a risk of vaccine-enhanced disease and, conversely, suggest efficacy against severe disease within the available follow-up period.”
The risk remains over time as immunity to the disease declines, the FDA said, and “needs to be further evaluated in ongoing clinical trials.”
What about children and pregnant women?
The data included only children aged 16 and over, although the study has since been extended to 12 years and will include younger children as soon as the company decides what dose it will test in this group.
Pregnant and lactating women were not included in the study, so there are no data to suggest whether they should avoid vaccination. In a meeting last week by a CDC group deciding how vaccines should be distributed, several expert members said they expected the vaccine would be safe for breastfeeding mothers because the virus itself does not appear to pass through breast milk.
Overall, Schaffner said the process of developing and testing the graduate vaccine will look simple in the face of the challenges of delivering it to a country of $ 328 million and above.
It will be, he said, “a much larger, longer, intensive, costly effort and will require great commitment, great perseverance, good communication.”
Other new surveys that Pfizer / BioNTech plans to conduct include: a survey of, among others, 20,000 U.S. health workers registered in the COVID-19 HERO registry; and a 30-month study using data from the Department of Defense Health System electronic health records to examine vaccine outcomes among covered U.S. military personnel and their families. Companies will also look for any side effects associated with the vaccine using the Veterans Health Administration electronic medical record database.
This article was originally published in USA TODAY: FDA Pfizer Vaccine Evaluation: Immunization Safe, Effective