The rapid detection of an ultra-rare blood clot reaction in some Covid-19 vaccine recipients demonstrated the strength of a federal vaccine safety alert system, but experts fear that blind spots in the program may inhibit the detection of other unexpected side effects.
Before the pandemic began, the Food and Drug Administration had scaled down a program it successfully used to track adverse events during and after the H1N1 flu pandemic in 2009, and the agency is still increasing its compensation, said Dr. Robert Chen, Scientific Director of Brighton Collaboration, a nonprofit global vaccine safety network.
FDA officials acknowledged that some data analyzes would not start in weeks or months, but said the government is keeping an eye on vaccine responses with “advanced” systems.
“The FDA and CDC have robust safety and efficacy monitoring systems for monitoring Covid-19 vaccines approved for emergency use in the United States,” Abby Capobianco, a spokesman for the FDA, wrote in an email.
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There is no doubt that the country’s vaccine monitoring system worked as expected in the spring, as it identified unusual cases of blood clots combined with low platelet counts in 15 people who had received Johnson & Johnson’s one-shot Covid-19 vaccine, Drs. Jesse Goodman, a former lead researcher at the FDA. Three people died.
“The good news for a very rare event is that it will appear on VAERS,” Goodman said in a call with reporters referring to the FDA and CDC’s Vaccine Adverse Event Reporting System since 1990.
But other potentially dangerous, unexpected reactions to vaccines may not be so obvious in VAERS, a system thought to miss many potential side effects – or in the country’s supplementary monitoring systems, including Vaccine Safety Datalink and CDC’s new telephone-based tracking program, v-safe.
“It’s a whole lot of different data collection systems,” said Dr. Katherine Yih, a biologist and epidemiologist who specializes in vaccine monitoring at Harvard Pilgrim Health Care. “It’s worth saying it’s not as good as it could be.”
Vaccine safety data link, although highly respected, did not include enough vaccinations within its data from nine hospital systems covering 12 million people to catch the J&J problem, CDC officials said. And enrollment in v-safe has been less than expected, with about 6 million people enrolled by the end of March, only 6.4 percent of those who had been vaccinated at the time.
This means that at a time when approx. 100 million Americans have been fully vaccinated against Covid-19, the United States continues to rely on a patchwork network of vaccine monitoring systems that may not monitor a large enough section of the population, experts told KHN.
“I’m very concerned about this,” said Goodman, who also headed the FDA’s Center for Biologics Evaluation and Research, or CBER and is now a professor of infectious diseases at Georgetown University. “I think we need to see that reporting on all these vaccines. It was promised four months ago that it happened. ”
The three vaccines in use in the United States – produced by Pfizer, Moderna and Johnson & Johnson – proved to be safe and effective during clinical trials with tens of thousands of volunteers.
However, even the best attempts are not large enough to capture all problems, especially rare if they occur only in certain groups or outside a certain time frame. It is important to track side effects when vaccines are distributed throughout the population – an effort known as pharmacovigilance – to ensure not only safety but also public confidence.
Vaccine safety experts said they were concerned that the FDA was downsizing a system known as the Post-Licensure Rapid Immunization Safety Monitoring network, or PRISM, long considered a workhorse for surveillance.
“Before PRISM, I felt like we were kind of in the dark ages,” Steve Anderson, director of the FDA’s Office of Biostatistics and Epidemiology, said at a workshop in 2016. “When PRISM came, it was really a game changer for us.”
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PRISM linked four major health plans in different parts of the country with eight state immunization registers. During the H1N1 pandemic, it detected signals for three side effects possibly associated with the vaccines and was used to rule out the two that were not related and one, Guillain-Barré syndrome, that was.
The system included records from nearly 40 million people, said Daniel Salmon, former director of vaccine safety at the National Vaccine Program Office. Having a large amount of records of vaccinated people “really drives your ability to figure out what’s going on,” he said.
PRISM, which was recycled for drug safety, now contains data from about 60 million people, but it has not been used to track vaccine reactions during the Covid-19 pandemic, said Salmon, who oversees safety monitoring of the H1N1 vaccine.
“With PRISM, we tested it in a crisis, and it worked for a decade,” he said. “I was really surprised when it was not used for Covid-19. That’s why we built it. ”
A newer system, called the Biologics Effectiveness and Safety System, or BEST, was launched in 2017, but only recently began monitoring data weekly for 15 predefined side effects among Medicare recipients. It is expanding to include commercial databases starting in late June, according to Capobianco, an FDA spokesman.
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A search for possible cases of the rare condition associated with the J&J vaccine began in mid-April and will be expanded in the next few weeks, she added.
FDA officials said PRISM’s capabilities have been incorporated into BEST, which can examine data from 100 million people. Experts told KHN that it has not been widely used to monitor effects after vaccination, but Capobianco said: “We disagree.”
“BEST is built as an advanced active monitoring system,” she wrote.
The concern is that officials have relied heavily on VAERS, a “passive” system that relies on reports from patients and healthcare providers to mark post-vaccination problems that may or may not be related to the shots. A robust “active” monitoring system can search large amounts of patient records to compare the number of side effects in people who received vaccines with those who did not.
In addition, some vaccine safety experts point to a lack of clear authority in the area. The Trump administration closed NVPO, a federal office with expertise in vaccine safety monitoring, and merged it into a government agency focusing on infectious diseases.
As a result, surveillance of Covid-19 vaccine safety is fragmented among federal agencies, said Salmon, who now heads the Department of Vaccine Safety at the Johns Hopkins Bloomberg School of Public Health.
“There is no single person in charge,” he said. “You have to have someone in charge.”
Biden administration officials have praised the nation’s vaccine monitoring system, pointing out that it marked Johnson & Johnson problems within weeks of the vaccine’s rollout. Federal officials temporarily halted distribution to assess further cases and next steps. They were helped by the fact that European regulators had found similar problems in another vaccine.
“VAERS performed exactly as intended in this case,” said Dr. Tom Shimabukuro, Head of the CDC’s Covid-19 Vaccine Task Force.
That is true, said Dr. Steven Black, Co-Director of the Global Vaccine Data Network. Still, he noted that there is room for improvement, especially more funding and better collaboration.
“This is a protection for our people,” Black said. “Whether it’s for flu vaccines or Covid vaccines, you need to have a viable and strong system. Just because we think they are safe does not mean you do not need systems in place to back that view. ”
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