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On Monday, the Food and Drug Administration (FDA) updated the label of the Johnson & Johnson vaccine to account for the possibility, however remote, that patients could develop a rare neurological condition called Guillain-Barré syndrome. This is not the crisis some might believe: The FDA has not been able to definitively establish whether the vaccine itself causes the disease, and the chances of contracting the disease from a COVID vaccine. 19 are lower than those of SARS-CoV. -2, the virus that causes COVID-19.
Even so, scientists who want to get as many people vaccinated as possible still recognize the need to be upfront about the possibility of vaccine side effects. Public confidence in science is facing a minor crisis, as evidenced by the number of Americans who believe in pseudo-scientific vaccine conspiracy theories; to this end, transparency about vaccines and their side effects is crucial to gaining public trust.
“How to communicate about vaccines is a real dilemma,” Michael Bang Petersen, professor of political science at Aarhus BSS, Aarhus University, told SciTechDaily. “Politicians have a desire to stop the pandemic as quickly as possible, and this may prompt them to mitigate the negatives of vaccines in order to vaccinate as many people as possible.”
However, reluctance to vaccinate may stem, in part, from a problem of basic scientific knowledge. Few Americans know the immunological reasons why vaccines can cause side effects. Indeed, immunology is not a subject taught in elementary or secondary schools – at least not in detail – in the United States.
Although vaccines sometimes have serious side effects such as swelling of the face and throat, difficulty breathing, dizziness and weakness, rash or rapid heartbeat, the symptoms are usually milder: chills and fever. .
So why do these things happen? The function of a vaccine is to give your immune system a helping hand, protecting you from pathogens (any microorganism, such as bacteria or viruses, that causes disease). Think of your immune system like a symphony orchestra: different instruments must be used for everything to work smoothly. Leukocytes (better known as white blood cells) directly attack pathogens by devouring them (phagocytes) or recording important information about them so that the body is on guard in the future, as well as helping to destroy them (lymphocytes). There are two types of lymphocytes, B lymphocytes which identify pathogens and T lymphocytes which eliminate them. B lymphocytes play an essential role here, as they create antibodies to recognize antigens (foreign substances) when they are detected.
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This is where vaccines come in. Their job is to help your lymphocytes recognize potential pathogens in a way that won’t put you at risk. They train the immune system to recognize pathogens by introducing either a weakened or dead version of the pathogen or (in the case of mRNA vaccines) a synthetic strand of RNA that will help cells produce proteins similar to those of the pathogen.
This is essential for understanding the origin of vaccine side effects. Like Jonathan Jarry M.sc. Written for McGill University, the immune system is wonderfully complex, meaning that there are many variables that play a role in how a vaccine is received by the body.
“Our immune system is a lot like those massive battle sequences in the ‘Lord of the Rings’ movies: impressive in scope and involving countless agents all performing different functions,” Jarry explained. For example, the immune system releases a molecule after a vaccination known as a vasodilator, which swells local blood vessels and can cause swelling and redness near the injection site. If other molecules released after a vaccination interact with the central nervous system, they can tell the brain to contract blood vessels and produce heat inside, causing chills.
The composition of the vaccine itself is also of crucial importance. Different vaccines contain varying amounts of the pathogen in question and use different adjuvants or included molecules to stimulate immune responses. These can play a role in how individual bodies respond to vaccines, as can the injection site (muscle injections usually cause fewer side effects than injections into subcutaneous fat). This means that often side effects are the result of reactions to the adjuvants, and not of the virus deactivated in the vaccine itself.
Since vaccines must be manufactured under sterile conditions and carefully controlled, any laxity or error on the part of the manufacturers can lead to side effects. The state of mind of the person receiving the injection also has an influence: if you are more stressed, you are more likely to experience an adverse reaction from stress hormones or simply to panic.
However, we don’t know much about vaccine side effects, for the simple reason that it can be very difficult to prove that a given medical problem was caused by a vaccine. Often there are no specific biomarkers to check that can determine if a vaccine has caused a given problem. In addition, since side effects can occur in the days or weeks after the vaccination itself, it is often difficult to know if a given problem was actually caused by the vaccine.
Fortunately, drug companies don’t want you to experience side effects more than you do, and as such, clinical trials are in place to protect consumers. These clinical trials are conducted in phases, although the phases are really considered separate trials. Scientists do not jump from developing a vaccine to administering it; they are extremely careful at every step of testing their vaccines on groups of patients to make sure they are safe and effective. Phase I involves a small group of people to determine if it is safe and induces a detectable immune response, researchers are moving to Phase II, which expands the study to include people from groups that are particularly in need of the vaccine, such as the elderly or sick. Phases III and IV further expand the group once the first two phases have revealed sufficient safety. They often include thousands of participants and last until a vaccine is released to the public.
Despite these safety measures, there have been a handful of major vaccine-related tragedies. In 1955, the government quickly approved a polio vaccine which then accidentally mass-produced a version that included live versions of the polio virus instead of inactivated versions. This fiasco became known as the Cutter Incident, leaving several hundred children paralyzed and around 10 dead. Then there was the batch of polio vaccines contaminated with the simian virus 40 (SV40), which comes from monkeys because scientists were growing the virus on tissues of rhesus macaques. This had an effect on 10 to 30% of polio vaccines distributed between 1955 and 1963.
These occasions are rare, and while there is evidence that the Johnson & Johnson vaccine caused the side effects that raised the alarm, it is still highly unlikely that there will be a fiasco comparable to the Cutter incident. . Scientific authorities are not trying to discourage people from getting vaccinated, but are advocating a nuanced approach to the subject. The risks of not getting the vaccine are much, much, much greater than the risks of getting the vaccine.
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