Accidental diseases threaten to give Covid-19 vaccines a bad name
As Covid-19 vaccines are widely used, some rare side effects of vaccination will almost certainly appear, such as reports of a small number of people developing anaphylaxis. But so will medical events, the timing of which depends purely on chance – and the potential spillover effects of these reports are already worrying experts.
Every day people die unexpectedly. They have strokes, heart attacks, and seizures. On average, 110 people in this country can develop Bell’s palsy, temporary facial paralysis, and 274 more will develop Guillain Barre syndrome, a form of paralysis that usually goes away over time. The trigger for these medical events is often not known. But when they do happen soon after someone has received a vaccine – especially a new one – well, conclusions will be drawn.
“It makes sense for people to say: this person suffered something and something serious happened in the hours or days that followed,” said Art Reingold, president of the epidemiology and biostatistics division. from UC Berkeley’s School of Public Health. “And if it was you or a member of your family, you would be inconceivable that this was not true.”
Except, of course, that this is often not the case. Heart attacks most often happen in the morning, but we don’t blame breakfast for causing them. A heart attack the day after a Covid-19 vaccine? It may be another matter.
But the public does not fully understand the concept that many problems that arise after vaccination are probably not related to the vaccination itself. This is in part because this context has been absent from public health messages on Covid-19 vaccinations.
“I think the general public is not at all prepared to understand this,” said Kate O’Brien, director of the WHO immunization, vaccines and biologicals program.
Quickly distinguishing a true side-effect signal from an abundance of noise will be essential to mitigate the alarm of an already cautious public about vaccines being developed at “warp speed,” experts have warned.
The risk that the public will misinterpret such anecdotal reports can be particularly acute early in the deployment, when the elderly and those with health concerns are given priority for immunization. Nursing home residents are in phase 1a – currently underway – and people aged 75 and over are in phase 1b. People aged 65 to 74 and those with medical conditions that increase the risk of severe Covid disease are in phase 1c. These are the people to whom medical events occur most often.
“Things are going to happen to them,” O’Brien said, although she noted that more medical woes would happen to people in these groups if they were not vaccinated.
Helen Keipp Talbot, who is part of the panel of experts who designed the priority vaccine distribution lists for the Centers for Disease Control and Prevention, actually voted against putting nursing home residents on the front line, in part because vaccinating unhealthy people in the first place could inadvertently undermine confidence in the vaccine, given the frequency of heart attacks, strokes and even deaths are in this population.
“All the events will be temporally associated. But how do you explain this to the caregiver who takes care of this patient and loves her like her own grandmother? Who then decides that she is not going to get the vaccine and tells everyone not to get the vaccine? Talbot told STAT.
“I fear a loss of confidence in the vaccine. That the vaccine will be really safe, but there will be associated events over time and people will be afraid to use the vaccine, ”said Talbot, associate professor of infectious diseases at Vanderbilt University.
In some cases, there is reason to believe that the reports of adverse events are likely due to the vaccine. Anaphylaxis – a potentially fatal allergic reaction – has been linked to several types of vaccines in the past.
Britain has reported several cases of anaphylaxis in people who received the Pfizer vaccine. In the United States, about 11 cases have been reported since the vaccine rolled out began earlier this month, according to the CDC. Most followed receipt of the Pfizer vaccine, but a Boston doctor with a shellfish allergy developed a severe allergic reaction after receiving the Moderna vaccine. If and when other Covid vaccines are authorized, health authorities will closely monitor whether anaphylaxis is linked to all Covid vaccines, or just those like the Pfizer and Moderna vaccines which are made from messenger RNA.
A three-year review of adverse reports recorded in a United States National Vaccine Database found that anaphylaxis after vaccination is rare, occurring at a rate of approximately 1.31 per million doses of vaccine administered. Of these cases, 85% involved people with a history of allergies. None of the 33 cases – out of 25 million vaccinations – died. Some needed epinephrine, the medicine in EpiPens, but others recovered after treatment with antihistamines.
Bell’s palsy has also been linked in at least one circumstance to a vaccine, an influenza vaccine administered intranasally which was briefly marketed in Switzerland.
Eight people in the Pfizer and Moderna trials, which enrolled nearly 74,000 participants in total, were diagnosed with the disease – seven in the vaccine arms and one in the placebo arm of the Moderna trial. The jury is still out on whether Bell’s palsy, which affects around 40,000 people a year in the United States, is an occasional side effect of taking a Covid-19 vaccine.
As vaccinations begin on a larger scale, reports of other potential side effects will likely emerge. A few cases of something are anecdotes, not data, and certainly not evidence of a causal relationship. While they must and will be investigated, investigations of this type take time.
The CDC and the Food and Drug Administration have a number of surveillance systems in place to monitor potential side effects, as some other countries do. But it’s going to be important to research and be prepared to respond to vaccine safety rumors wherever they start to swirl, said Steven Black, professor emeritus at the University of Cincinnati Children’s Hospital whose career focused on vaccine safety.
“The reason I think you have to think globally is that vaccine alerts are global,” said Black, who is also co-director of the Global Vaccine Data Network, a 17-country collaboration that studies safety and health. effectiveness of vaccines. “We know very well that disinformation spreads much faster than information, so a few deaths in Brazil or one death in Indonesia or whatever, the public outcry could cause a lack of confidence and undermine the whole program of vaccination.”
“Once there is a report that people read, no matter what we categorically prove two years later in a study, that perception will remain, and it’s hard to fight,” he said. .
This is why it is so crucial to set expectations before and during an immunization campaign. But public literacy about vaccination – the benefits, the risks and how to balance the two – is low, said O’Brien, who highlights how often people insist on getting the flu as a result. influenza vaccine, even if it is biologically impossible.
One of the ways that vaccine experts try to combat the rise in rumors and unsubstantiated claims is by knowing the baseline rates of medical events, so that when things do happen, one can know if the number case is abnormal or what one would expect. occur whether or not a vaccination program is in progress.
“If we know that Guillain Barré occurs in 1 in 100,000 people and one million people have been vaccinated, you might expect 10 cases,” Black explained. “But if you have 30, you start to wonder: maybe there is a problem here?” So knowing the base rates as a frame of reference is something that is promoted. “
Differentiating what is relevant and what is not is going to be difficult, especially with several new vaccines (hopefully) starting to be used in a short period of time. When suspicious medical events do occur, it will be important to know what vaccine the person in question has received – although this can be a bigger challenge than expected. Keeping records for vaccinations – especially adult vaccinations – is not close to where it should be, O’Brien said.
If it becomes clear that one, some or all of the vaccines have rare risks of side effects, how will the public take the news?
“At some point, if things happen, one in 100 million [vaccinations], people may be willing to accept this risk if it allows the world to get rid of Covid and return to normal life, ”Black said. “Because you have to remember that hundreds of thousands of people are dying from the disease. “
However, how this risk is communicated will be crucial, as many people cannot easily understand how to assess the significance of a rare risk. “They are wary of very rare events and then they text as they cross the street where they are much more likely to be killed. Yeah, people do that very badly, ”Black said.
Giving people a comparison that makes sense to them can help, said Alison Buttenheim, associate professor of nursing and health policy at the University of Pennsylvania who works on vaccine acceptance.
The idea that one in 500,000 people vaccinated against Covid could have a serious side effect – this is a hypothetical example – may seem too risky for some people. Explaining to them that they run the same risk of being struck by lightning in any given year can make this information take a different turn.
Likewise, pointing out that one in 500 New Jersey residents have already died from Covid-19 may remind people that the risk of not being vaccinated far outweighs the rare risks that vaccines can potentially pose, Buttenheim said.
Ultimately, helping the public understand these issues requires communication – and it doesn’t happen nationally, said Bruce Gellin, president of global immunization at the Sabin Vaccine Institute, which promotes access to immunizations.
The Department of Health and Human Services, not the CDC, has taken the lead in communication efforts on the Covid vaccine. But its production to date has been limited.
“It would have been nice if they could come up with a communications strategy at the same warp speed as that of vaccines,” said Gellin, former director of the National Vaccine Program Office at HHS.
“My mantra is that there is a world of vaccines and there is a world of vaccination, and they are not necessarily connected by an arrow. [Operation] Warp Speed was largely about the vaccine world and logistics, ”Gellin said. “Unfortunately, Warp Speed was not about a vaccination program. And now what we are seeing is that we are now facing the vaccination program and we are under-prepared. “