Dangerous Side Effects Of Vaccines - Viralzoon

Dangerous Side Effects Of Vaccines


Vaccination protects against a disease that can be serious

  • Safety is a major imperative for vaccines as they are administered to healthy people (often children).
  •  If no vaccine is either completely free of side reactions or totally effective, vaccination is one of the most cost-effective treatments. Vaccination has led to a significant reduction of many diseases, even a loss for some, inducing, by cons, a focus of attention on clinical manifestations reported after vaccination (adverse effects).
  •  While some of these events are actually due to vaccines (side reactions), others are only the result of coincidences (undercurrent events), because of the most vaccinations carried out (several million people each year).
  • The majority of vaccine controversies (multiple sclerosis, myofasciitis with macrophages, autism, etc.) have received unambiguous scientific answers: there is no evidence or suspicion of proof that vaccines are involved in these diseases.

The goal of vaccine development is to obtain a product with the highest level of protection with the lowest rate of side reactions. Their surveillance is given special attention. In addition to the traditional surveillance systems provided by the pharmacovigilance centers and the pharmaceutical laboratories, several structures have been set up around the world, in order to reinforce the effectiveness of the vaccine-vigilance and to be able to determine, if necessary, causal links. between observed manifestations and vaccines. (Box 1) In industrialized countries, vaccine-preventable diseases have become very rare as soon as a strategy has been put in place allowing high vaccination coverage. As a result, the general (and medical) population is now unaware diseases such as tetanus, diphtheria, systemic Haemophilus influenzae serotype b infections. On the other hand, the attention is now focused on the clinical manifestations reported after vaccination

Adverse reactions or side reactions: ambiguity must be removed

Given the number of children vaccinated and the number of injections performed (10 in the first two years of life, according to the French vaccination calendar), it is inevitable that clinical manifestations occur during the course of vaccination and that a causal link is mentioned by parents or doctors. All of these concerns should be considered and explained in the first place.Pharmacovigilance, which is responsible for monitoring drugs, defines as “undesirable effects” harmful and unwanted reactions suspected to be due to a drug and as “undesirable events”, harmful and unhealthy manifestations. sought, without prejudging the link with the drug. In one case as in the other, no proof is made of the involvement of the drug. Some of these effects or adverse events are due to coincidence only (the symptoms or the disease would have been observed even in the absence of vaccination), these are intercurrent events. Others are caused by the administration of the vaccine. A causal link that could be established with the product, it is then secondary reactions (or effects). The WHO uses another terminology. It defines as undesirable post-vaccination events (AEFI), any adverse event that follows vaccination, whether or not it has a causal link with the use of the vaccine. Five groups are thus defined

  1. Reaction to the vaccine product
  2. Reaction to a vaccine quality problem
  3. Vaccination error response
  4. Vaccination anxiety reaction
  5. Coincidence: caused by something other than the vaccine

Side effects and side reactions of childhood vaccines

The greatest frequency of clinical manifestations reported after vaccination in children is essentially due to two reasons:

  • The immunization schedule concentrates administrations in the first two years of life to protect infants early;
  • Viral and bacterial infections that are particularly frequent at this time of life, give clinical signs that can be mistaken for vaccines. Some symptoms, such as fever, unexplained irritability, seizures, are common in young children, who are, in fact, the most vaccinated population.

Side effects and side reactions of the first two years of life

  • Local reactions: the most common
  • General reactions
  • Serious allergic reactions: very rare

The greatest frequency of clinical manifestations reported after vaccination in children is essentially due to two reasons:

  • the immunization schedule concentrates administrations in the first two years of life to protect infants early.
  • particularly frequent viral and bacterial infections at this stage of life, give clinical signs that can be mistakenly attributed to vaccines. Some symptoms, such as fever, unexplained irritability, seizures, are common in young children, who are, in fact, the most vaccinated population. The adverse effects of all vaccines can be classified into three groups
  • local reactions, the most frequent and benign manifestations, whose imputability to the vaccine leaves little doubt.
  • general reactions, whose accountability may be more difficult to assert, given their nonspecific nature and their frequency of spontaneous manifestation in the general population.
  • finally, the exceptional serious allergic accidents that can be life-threatening.

Local reactions The most frequent

reactions due to vaccines, they may be more or less important for some vaccines. Apart from BCG for which local reactions are delayed and prolonged, for other vaccines, they generally appear in the hours following administration, are most often limited and heal spontaneously. They are observed more frequently with inactivated vaccines containing adjuvants such as aluminum hydroxide. They are more numerous and important during subcutaneous injections than intramuscular, or the need to use needles of sufficient length. Much more rarely, these reactions by their magnitude, can evoke (most often atort) a bacterial infection.Three mechanisms can be involved:

  • Most often, these phenomena are hypersensitivity phenomena like Arthus, especially with tetanus and diphtheria vaccines. Reactions may be due to hyper-immunization as evidenced by very high levels of antibodies, usually secondary to repeated doses of vaccines. The characteristic here is the importance of pain. • Sometimes, intolerance to aluminum, the main adjuvant of many non-live vaccines, may be involved. The reactions are then observed after the injection of each vaccine containing aluminum (pentavalent, tetravalent, hepatitis b, conjugated vaccines …).
  • Finally, after different vaccines, an extensive edematous, non-inflammatory, non-painful local reaction may occur whose etiology remains unknown. These important local reactions do not constitute contraindications to subsequent vaccinations because recurrence is not systematic. Nevertheless, they invite to raise the question of the individual benefit of vaccination for a child.

General reactions

These are fever, malaise, myalgia, headache, anorexia, asthenia …. In the case of inactivated vaccines, these episodes are witnesses to the activation of the immune response and always occur within 48 hours after In live vaccines, they usually occur several days after the injection, at the time of maximum viral replication, and correspond to a minor form of the disease.
In both cases, children / parents should be informed of the risk of these symptoms to reassure and avoid unnecessary consultation. Vaginal discomfort (more rarely syncope) may occur within minutes of vaccination, especially in adolescents and young adults. One should be aware of the first vagal signs (feeling dizzy or weak) and keep the person who has just been vaccinated while sitting or lying to prevent possible trauma or wounds secondary to a fall.

Allergic reactions

severe These are allergic reactions of the avaccinenaphylactic type.They are mediated by IgE, can be caused by vaccine antigens or by other components of the vaccine (preservatives, traces of antibiotics …) .They are exceptional (less than 1/500 000 doses), but their gravitepotential (vital risk) implies that any healthcare professional vaccination is surrounded by the usual precautions (post-vaccination surveillance and adrenaline injectable adisposition). These reactions occur in a very short time (minutes or hours). -In reality less than an hour) after injection.The spectrum of clinical manifestations ranges from generalized urticaria (more than 90% of cases) to collapse, through painless edema of the face and mouth, the sneezing, coughing, difficulty breathing, wheezing.In addition to symptomatic measures, the basis of the treatment of anaphylactic manifestations is the subcutaneous or intramuscular injection of epinephrine (0.01 ml / kg of an aqueous solution of epinephrine 1/1000, to be renewed once, twenty minutes after if necessary, without exceeding 0.5 ml). The monitoring of the patient for a few hours in hospital is most often necessary. This risk of allergic reaction can be reduced by a rigorous interrogation preceding the vaccination procedure: any such manifestation occurring after the administration of a vaccine or One of its components is a formal contraindication to the iterative administration of this vaccine until an allergological investigation has been made on the possible link of causality. This exploration seems necessary because, even if the chronological link is obvious, it turns out that the occurrence of anaphylactic-like manifestations in the hour following a vaccination procedure is rare and especially rarely confirmed


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