The following article tries to shed light on the vast world of adverse reactions, with a specific look at the one against Tetanus, but we urge you to read all the focuses reported below to understand the other related issues, such as the problem of multiple vaccines, the hypersensitivity to one or more vaccine compounds, the SIDS problem and that of adjuvants. Most of the vaccines on the market are produced, for commercial purposes, in often multiple formulations and this makes the topic of vaccine damage much broader.

Many published studies have reported serious adverse reactions following tetanus toxoid vaccination. Adverse events include anaphylaxis,^(1-2) brachial neuritis,⁽³⁾ bullous pemphigoid^(4-5-6) Guillain-Barre syndrome (GBS),^(7-8) acute disseminated encephalomyelitis (ADEM),⁽⁹⁾ erythema multiforme,^(10-11-12) myocarditis,^{(13-14-15-16-17)} arthritis,^(18-19) optic neuritis,^(20-21) and other autoimmune disorders.^(22-23)

The undesirable effects reported after tetanus vaccination were collected by a German author⁽²⁴⁾ and by the Monitoring System for Adverse Events Following Immunization⁽²⁵⁾ and can be divided into two groups: local side effects and systemic side effects.

We can say that these effects depend on various factors:

• age of the recipient of the vaccine;
• physiological and pathological conditions of the recipient of the vaccine;
• number of vaccine doses taken;
• amount of tetanus toxin administered;
• presence of other bacterial and/or viral antigens associated with tetanus toxin;
• presence of adjuvants or other associated toxic substances.

It is believed that the undesirable effects caused by the first administration of the tetanus vaccine are superimposable to those that can occur with booster doses and if administered too frequently create a state of hyperimmunization which considerably increases the risk of vaccine damage and for this reason many studies scientists recommend not to administer boosters of this vaccine at intervals of less than 10 years.⁽²⁶⁾ Added to this is that the pediatric tetanus anatoxin contained in the combined vaccines is greater than that used for adults because, due to immune immaturity, it is necessary to overstimulate the newborn to obtain an adequate antibody response.

The most common and usually milder and transient local side effects of tetanus vaccination⁽³²⁾ they are caused by a particular hypersensitivity to tetanus toxin and are represented by: pain (50-85% of cases), redness, hardening and swelling (25-30% of cases) even up to abscess.⁽²⁷⁾ In some cases the local reactions have been particularly serious, such as Lyell's syndrome (or scalded skin syndrome) which has a mortality rate of 50% in adults and 25% in children.⁽²⁸⁾

All local side effects are more frequent if the vaccine is administered subcutaneously rather than intramuscularly. These effects increase with increasing amount of inoculated tetanus toxin⁽²⁹⁾ and this occurs especially in subjects who have had several and frequent injections of tetanus vaccine.^(30-27)
A 2017 study shows that among children with extensive limb swelling after receiving the fourth dose of the diphtheria-tetanus-acellular pertussis vaccine, recurrence of the local reaction was particularly frequent after the fifth dose of the vaccine (78% of vaccinated).⁽³¹⁾ 

Side effects also increase if the tetanus vaccine is combined with other vaccines, rather than used alone.⁽³²⁾

In 1994, the US Institute of Medicine (IOM) reported that there was compelling scientific evidence to conclude that tetanus, DT, and Td vaccines can cause Guillain-Barre syndrome (GBS), including death, brachial neuritis, and died from anaphylaxis (shock).⁽³³⁾ The IOM also recognized that there is an individual susceptibility to vaccine reactions for genetic, biological and environmental reasons, but that vaccine suppliers cannot accurately predict who will suffer complications, injury or death before a vaccine is administered. due to vaccination.⁽³⁴⁾

In 2017, Guinea-Bissau researchers compared the mortality rates of infants vaccinated against diphtheria, tetanus, and whole-cell pertussis (DTP) between 3 and 5 months of age with those of infants not yet vaccinated with the DTP vaccine. finding that all-cause mortality rates were significantly higher among infants vaccinated with the DTP than among those not yet vaccinated. The researchers also noted that if the oral polio vaccine (OPV) was given at the same time as the DTP vaccine, all-cause mortality rates decreased, but still remained significantly higher than in unvaccinated children.⁽³⁵⁾

An important local undesirable effect that can be found with relative frequency in adults is neuropathy of the brachial plexus,⁽³⁶⁾ if the inoculation is performed in the arm, and appears a few days or weeks after vaccination⁽³⁷⁾. This neuropathy is characterized by muscle pain, weakness, and muscle wasting. In addition to the neuropathies localized to the area where the vaccine was inoculated, in the literature we also find various other reports of localized neuropathies caused by the anti-tetanus administration,^(38-39) such as the involvement of various cranial nerves^(40-41) or eye nerves⁽⁴²⁾ or the recurrent laryngeal nerve.⁽⁴³⁾

The most common systemic effects of tetanus vaccination⁽³²⁾ can be divided into:

• non-specific effects, such as fever, headache (which is a fairly common side effect following vaccination), myalgias, urticaria, nausea, vomiting,⁽⁴⁴⁾ asthenia, anorexia, irritability, somnolence, 
• specific effects, such as anaphylactic shock, generalized neuropathies, intense abdominal pain with diarrhea, various inflammatory forms, even serious ones, and in some rare cases even death.

Among all the most common and numerous systemic effects we find neurological damage⁽⁴⁵⁾ and among these, polyneuropathy affecting the peripheral nervous system must certainly be placed first. It is more frequent than the involvement of the central nervous system and can appear both after the first dose of the vaccine and after the third.⁽⁴⁶⁾ Polyneuropathy usually occurs within a few minutes to a few hours (in the case of acute allergic reactions) or within 12-48 hours (in the case of delayed allergic reactions) or at most within 4-14 days of inoculation (in the case of neuritis ).⁽⁴⁷⁾ Polyneuropathy can affect a few nerves or large areas of the body up to involving the medulla and cerebral cortex and can only be caused by the tetanus vaccine⁽⁴⁸⁾ or from the administration of other vaccines combined with that of tetanus.^(36-49) 

Among the various forms of polyneuropathy, the following have been reported: demyelinating polyneuropathy;⁽⁵⁰⁾ asymmetric polyneuropathy; polyradiculoneuritis with bladder and rectal paresis;⁽⁵¹⁾ scarlatiniform rash,⁽⁴⁰⁾ acute urticarial reactions,⁽⁴⁴⁾ paralysis of the respiratory nerves (Landry's palsy), which can also lead to death;^(52-53) tetanic spasms;⁽⁴⁴⁾ transverse myelitis;⁽⁵⁴⁾ Guillain-Barré syndrome;^(55-56) peripheral motor aphasia;⁽⁵⁷⁾ and death.⁽²⁸⁾