The rapid detection of an ultra-rare blood clotting reaction in some Covid-19 vaccine recipients has shown the strength of the federal vaccine safety warning system, but experts worry that blind spots in the program could prevent the detection of other unexpected side effects.
Before the pandemic began, the Food and Drug Administration reduced the program it successfully used to track adverse events during and after the 2009 H1N1 flu pandemic, and the agency is still increasing its replacement, said Dr. Robert Chen. Scientific Director of Brighton Collaboration, a global network for the safety of non-profit vaccines.
“It was extremely unfortunate that they were between the systems when Covid struck,”
FDA officials acknowledged that the analysis of some data would not begin for weeks or months, but said the government was monitoring vaccine reactions with “state-of-the-art” systems.
“The FDA and CDC have robust safety and efficacy monitoring systems to monitor Covid-19 vaccines approved for emergency use in the United States,” Abby Capobianco, an FDA spokesman, wrote in an email.
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There is no doubt that the country’s vaccine monitoring system worked as expected this spring, when it found unusual cases of blood clots combined with low platelet counts in 15 people who received the disposable Covid-19 vaccine from Johnson & Johnson, he said. Dr. Jesse Goodman, a former FDA chief scientist. Three people died.
“The good news about a very rare event is that it will appear on VAERS,” Goodman told reporters, citing the Vaccine Adverse Event Reporting System, jointly managed by the FDA and CDC since 1990.
But other potentially dangerous, unintended reactions to vaccines may not be as obvious in VAERS, a system thought to miss many potential side effects – or in additional country monitoring systems, including Datalink for vaccine safety and new follow-up. on the phone on CDC program, v-safe.
“It’s quite a mix of different data collection systems,” said Dr. Catherine Jiech, a biologist and epidemiologist who specializes in monitoring vaccines at Harvard Pilgrim Health. “It’s worth noting that he’s not as good as he could be.”
The vaccine safety data sheet, while highly valued, does not include enough vaccinations in its data from nine hospital systems covering 12 million people to catch the J&J problem, CDC officials said. And enrollment in v-safe is lower than expected, with about 6 million people enrolled at the end of March, only 6.4 percent of those vaccinated so far.
This means that at a time when about 100 million Americans have been fully vaccinated against Covid-19, the United States continues to rely on a patch network of vaccine monitoring systems that may fail to monitor a large enough population, experts said. before KHN.
“I’m very concerned about that,” said Goodman, who also heads the FDA’s or CBER’s Center for Biological Products Assessment and Research and is now a professor of infectious diseases at Georgetown University. “I think we need to monitor this reporting for all these vaccines. It was promised that this would happen four months ago. ”
The three vaccines used in the United States – manufactured by Pfizer, Moderna and Johnson & Johnson – have been shown to be safe and effective in clinical trials of tens of thousands of volunteers.
But even the best trials are not large enough to cover all problems, especially rare ones if they occur only in certain groups or outside a certain period of time. It is important to monitor side effects once vaccines are distributed to the population – an effort known as pharmacovigilance – to ensure not only safety but also public confidence.
Vaccine safety experts have said they are concerned that the FDA has downgraded the system known as the Safety Post-License Immunization Safety Network or PRISM, long considered a surveillance workhorse.
“Before PRISM, I felt like we were in the dark ages,” said Steve Anderson, director of the FDA’s Office of Biostatistics and Epidemiology, during a seminar in 2016. “When PRISM came along, it really changed the game for us.”
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PRISM links four major health plans in different parts of the country to eight state immunization registries. During the H1N1 pandemic, he found signals of three adverse events possibly related to the vaccines, and was used to rule out two unrelated ones, and this one, Guillain-Barré syndrome, which was.
The system includes records of nearly 40 million people, said Daniel Salmon, a former director of vaccine safety at the National Vaccine Service. Having a large volume of records of vaccinated people “really drives your ability to understand what’s going on,” he said.
The PRISM, which was modified for drug safety, now contains data from about 60 million people, but was not used to track vaccine reactions during the Covid-19 pandemic, said Salmon, who heads the safety monitoring of the H1N1 vaccine.
“PRISM and I tested it in a crisis and it worked for a decade,” he said. “I was really surprised when it wasn’t used for the Covid-19. That’s why we built it. “
A newer system, called the Organic Product Efficacy and Safety System, or BEST, was launched in 2017, but only recently began monitoring weekly data on 15 pre-determined adverse events among Medicare recipients. It will be expanded to include commercial databases from the end of June, according to Capobianco, an FDA spokesman.
There is no responsible person. You have to have someone responsible.
The 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 are included in BEST, which can examine data from 100 million people. Experts told KHN that it is not widely used to monitor the effects after vaccination, but Capobianco said: “We do not agree.”
“BEST is built as a modern system for active monitoring,” 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 signal post-vaccination problems that may or may not be related to the photos. . A robust ‘active’ surveillance system can look for large volumes of patient care records to compare the incidence of adverse events in people who have received vaccines with those who have not.
In addition, some vaccine safety experts point to a lack of clear authority in the area. The Trump administration has shut down the NVPO, a federal office with experience in monitoring vaccine safety, merging it into a government agency focused on infectious diseases.
As a result, monitoring the safety of Covid-19 vaccines has been fragmented among federal agencies, said Salmon, who now heads the Vaccine Safety Institute at the Johns Hopkins Bloomberg School of Public Health.
“There is no one in charge,” he said. “You have to have someone to answer.”
Biden officials praised the national vaccine monitoring system, saying it reported Johnson and Johnson’s problems within weeks of the vaccine being released. Federal officials stopped the distribution to assess further cases and next steps. They were helped by the fact that European regulators have found similar problems in another vaccine.
“VAERS performed exactly as planned in this case,” said Dr. Tom Shimabukuro, head of the CDC’s Covid-19 Vaccine Working Group.
That’s true, said Dr. Stephen Black, co-director of the Global Vaccine Data Network. Still, he noted, there is room for improvement, especially more funding and better co-operation.
“This is a precautionary measure for our population,” Black said. “Whether it’s flu vaccines or Covid vaccines, you need a viable and strong system. Just because we think they’re safe doesn’t mean you don’t need systems to support that view. “
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