WWhile the world awaits the results of large clinical trials of Covid-19 vaccines, experts say the data so far suggests an important possibility: the vaccines may be a little difficult.
In the language of vaccines, they appear to be “reactogenic,” meaning that they have caused short-term discomfort in a percentage of people who have received them in clinical trials. This type of discomfort includes headache, arm pain, fatigue, chills, and fever.
As long as the side effects of potential Covid-19 vaccines are transient and not serious, they would not be a source of alarm; in fact, they may be signs of an accelerating immune system. It is a simple fact that some vaccines are more unpleasant than others. Think about the pain of a tetanus shot, for example.
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But experts say it makes sense to prepare people now for the possibility that Covid-19 vaccines may be reactogenic.
“I think one of the things that we will have to realize is that all of these vaccines will be reactogenic … they will all be associated with reactions,” said Kathryn Edwards, scientific director of the Vanderbilt Vaccine Research Program in Nashville, Tenn.
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“I think if you had to point that out, look, this is going to be a little painful, but there is an end and there is a greater good to be gained here, I think it’s probably worth it,” agreed Brian Southwell, senior director of the science program. in the public sphere at the Center for Communication Sciences at RTI International, an expert group located in Research Triangle Park, NC
At least two manufacturers, Moderna, based in Cambridge, Massachusetts, and CanSino, a Chinese vaccine manufacturer, stopped testing the highest doses of their Covid-19 vaccines due to the number of serious adverse events reported among participants in their clinical trials.
Ian Haydon, one of the volunteers who received the highest dose in the Moderna Phase 1 clinical trial, ended up seeking medical attention after he had risen from 103 Fahrenheit fever 12 hours after receiving a second dose of the vaccine. (Most Covid-19 vaccines will probably require two doses to work.)
Side effects are seen in several different vaccines, made in different ways. This does not appear to be a problem related to a specific type of Covid-19 vaccine.
The University of Oxford-AstraZeneca vaccine, which uses a virus harmless to humans that infects chimpanzees as a backbone, saw adverse events reported by 60% of recipients in their initial testing phase, reported last week in The Lancet magazine. Half of the patients who received the highest dose of the Pfizer-BioNTech vaccine, which like Moderna is a messenger RNA vaccine, reported side effects.
Even after dropping out of the highest-dose study, CanSino saw that nearly three-quarters of people in the vaccine arms in its phase 2 trial reported side effects, although none were serious. The CanSino vaccine uses a human adenovirus as the backbone.
Preparing people for the fact that Covid-19 vaccines can be reactogenic allows them to know what to expect when the vaccine becomes available, said Kathleen Neuzil, director of the Center for Vaccine Development at the University of Maryland School of Medicine. .
“As with many vaccines, we have found that if we let people know what to expect, then they have less worry if side effects occur,” said Neuzil.
There is plenty of evidence that people will accept reactogenic vaccines, practically rush to obtain them, if they are concerned enough about the condition that the vaccine is designed to prevent.
Edwards said GSK’s Shingrix herpes zoster vaccine, which reportedly makes people feel quite miserable for a short period after injection, is a perfect example. Despite the potential for discomfort, from the moment the vaccine was released to the market, the company was unable to keep up with demand. (GSK recently announced that the vaccine was no longer in short supply.)
Most people know someone who has had herpes zoster; You have heard how painful the condition, a reactivation of the latent chickenpox virus, a late side effect of chickenpox infection, for people who develop it.
But the behavior of many Americans suggests that they don’t see Covid-19 as a particular threat, as many resist wearing masks and follow recommendations for social distancing that have successfully decreased transmission in other parts of the world.
A variety of surveys suggest that between half and 70% of Americans plan to get vaccinated when Covid-19 vaccines become available, figures that raise concerns in some quarters about the ability of the vaccines to activate collective immunity in the population of USA
Noel Brewer, professor of health behavior at the University of North Carolina, is not concerned at the moment with those election numbers. Currently, it is not even clear if the vaccines will work, he said, which means that pollsters are asking people about what-if decisions they may have to make at some unknown time in the future.
“It’s all just a bunch of question marks,” said Brewer, who actually thinks the poll numbers look pretty good in these circumstances. “Once people are faced with a specific vaccine and a particular effectiveness profile, etc., they can make a decision based on one thing, rather than an idea of one thing.”
For most people right now, Covid-19 is invisible “unless you are in an ICU,” he said. “For most of us every day, we don’t see people who are really sick.”
Brewer, who is part of a World Health Organization subcommittee on the safety of Covid-19 vaccines, said people expect some discomfort when getting vaccinated.
“The real question is: how much discomfort compared to what other things you may be facing? So if you are 70 years old and you cannot leave your house, you will have a calculation compared to if you are someone who is 20 years old, ”he said.
The conditions at the time the vaccine is ready for use will be a major influencing factor when vaccines are offered to the public, Southwell said. In the meantime, however, he believes it is essential to communicate with the public on issues such as how vaccines are manufactured and that Covid-19 vaccines can be reactogenic.
People are paying attention to these issues, he said, arguing that members of the public have a greater capacity for understanding than is generally credited.
“There could be a much bigger case of acceptance if we do our job to build trust now and lay the groundwork now,” said Southwell. “But we are not necessarily as focused on that as we could be.”
